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Stroke

Stroke

Definition

A stroke, also called a cerebral infarction, is a life-threatening condition marked by a sudden disruption in the blood supply to the brain.

Description

A disruption in the blood supply to the brain starves the brain of oxygen-rich blood and causes the nerve cells in that area to become damaged and die within minutes. The body parts controlled by those damaged brain cells lose their ability to function.

Depending on the area of the brain that is affected, a stroke can alter many aspects of a child's functioning such as speech, movement, behavior and learning. A stroke also may cause weakness or paralysis on one side of the body. The loss of function may be mild or severe, temporary or permanent.

If medical treatment begins within hours after symptoms are recognized, brain damage can be limited and the risk of permanent medical effects can be decreased.

Types of stroke

An ischemic strokethe most common form of stroke in children under age 15is caused by a blocked or narrowed artery. In children, blockages may be caused by a blood clot, injury to the artery, or rarely in children, atherosclerosis (build-up of fatty deposits on the blood vessel walls). A cerebral thrombosis is a blood clot that develops at the clogged part of the blood vessel. A cerebral embolism is a blood clot that travels to the clogged blood vessel from another location in the circulatory system.

A hemorrhagic strokethe more common form of stroke in infants and children under age twooccurs when a weakened blood vessel leaks or bursts, causing bleeding in the brain tissue or near the surface of the brain.

Two types of weakened blood vessels usually cause hemorrhagic stroke, including:

  • aneurysm: ballooning of a weakened area of a blood vessel
  • arteriovenous malformations: cluster of abnormal blood vessels

A transient ischemic attack (TIA), also called a "mini stroke," is characterized by a short-term blood vessel obstruction or clot that tends to resolve itself quickly, usually within 1020 minutes, or up to 24 hours. A TIA usually does not require intervention. However, a TIA is a strong indicator of an ischemic stroke and should be evaluated in the same way as a stroke to prevent a more serious attack.

In children, strokes can be categorized as:

  • prenatal stroke: occurring before birth
  • neonatal or perinatal stroke: occurring in infants less than 30 days old
  • pediatric or childhood stroke: occurring in children aged 15 and under

Demographics

Childhood stroke is relatively rare, occurring in about two to three of every 100,000 children aged one to 14 per year. In comparison, stroke occurs in about 100 of every 100,000 adults per year. The rate of ischemic stroke and hemorrhagic stroke is similar among children aged one to 14.

Stroke occurs more frequently in children under age two, and peaks in the perinatal period. In the National Hospital Discharge Survey from 1980-1998, the rate of stroke for infants less than 30 days old (per 100,000 live births per year) was 26.4, with rates of 6.7 for hemorrhagic stroke and 17.8 for ischemic stroke.

More fatal strokes occur in African-American children than white children, mirroring the racial differences of stroke in adults. Compared to the stroke risk of white children, African-American children have an increased relative risk of 2.12, Hispanics a decreased relative risk of 0.76 and Asians have a similar risk. Boys have a 1.28-fold higher risk of stroke than girls and have a higher case-fatality rate for ischemic stroke than girls. The increased risk among African Americans is not explained by the presence of sickle cell disease, nor is the excess risk among boys explained by trauma.

Research conducted by the National Institute of Neurological Diseases and Stroke (NINDS) indicates a "stroke belt," or geographical area where fatal strokes are more predominant. This stroke belt includes Alabama, Arkansas, Georgia, Indiana, Kentucky, Louisiana, Mississippi, North Carolina, South Carolina, Tennessee, and Virginia. Researchers examined death certificates over a 19-year period and found a 21 percent higher risk of death from stroke in people under age 20 in the stroke belt states had compared with the same age group in other states. During the same period, people over age 25 in the stroke belt region had a 20 percent higher risk of death from stroke. Because the overall rate of stroke in children is low, researchers warn parents in these states not to be too alarmed. However, the findings indicate further investigation is needed.

Causes and symptoms

Causes

The cause of childhood stroke is unknown in one-third of cases, and an underlying medical condition or multiple conditions appear to contribute to over half of the cases. The most common causes of stroke are congenital (present at birth) and acquired heart diseases, and sickle cell anemia .

About 1015 percent of children with sickle cell disease suffer a stroke, usually ischemic stroke. Sickle cell disease is a blood disorder in which the blood cells cannot carry oxygen to the brain because the blood vessels to the brain are either narrowed or closed.

One rare cause of stroke is an extreme case of the chickenpox virus, which causes a narrowing of blood vessels in the head for some children.

RISK FACTORS Although obesity , high cholesterol , high blood pressure, atherosclerosis, and smoking are common stroke risk factors in adults, they rarely contribute to stroke risk in children. Risk factors for childhood stroke include a family history of stroke, cardiovascular disease or diabetes, as well as the presence of the conditions listed below.

Some of the more common congenital heart diseases that increase the risk of childhood stroke include:

  • aortic and mitral valve stenosis
  • atrial septal defect
  • patent ductus arteriosus (PDA)
  • patent foramen ovale
  • inherited blood clotting disorders
  • ventricular septal defect
  • hypercoagulable states

Some of the acquired heart conditions that increase the risk of childhood stroke include:

  • bacterial meningitis
  • endocarditis
  • arrhythmia and atrial fibrillation
  • artificial heart valve
  • myocarditis
  • cardiomyopathy
  • rheumatic heart disease
  • embolism
  • anoxia
  • antiphospholipid antibody syndrome
  • encephalitis
  • blood vessel disease
  • certain blood disorders, such as hemophilia
  • inborn errors of metabolism
  • illicit drug use
  • teenage pregnancy
  • teen use of oral contraceptives (birth control pills)

Possible traumas that increase the risk of childhood stroke include birth injury or trauma, child abuse, or other injury or trauma.

Because of the wide range of secondary conditions that contribute to stroke, it is difficult for researchers to assess the relative contribution of each risk factor to the problem of cerebrovascular disease as a whole, according to the Child Neurology Society Ad Hoc Committee on Stroke in Children. In addition, this variability also hinders clinical research.

Symptoms

In infants and very young children, stroke symptoms are sudden and include:

  • seizures
  • coma
  • paralysis on one side of the body
  • nausea or vomiting

In older children, stroke symptoms are sudden and include:

  • numbness or weakness of the face, arm, or leg, especially on one side of the body
  • confusion or difficulty speaking or understanding speech
  • vision difficulties, often in one eye
  • hearing problems, often in one ear
  • difficulty walking, dizziness or loss of balance or coordination
  • severe headache
  • difficulty swallowing
  • nausea or vomiting
  • painful or stiff neck

Other stroke signs and symptoms include:

  • sudden severe headache with unknown cause
  • sudden nausea or vomiting
  • warm, flushed, clammy skin
  • slow, full pulse
  • appearance of unequal pupils
  • facial "droop" on one side
  • salivary drool
  • urinary incontinence

If the child seems to recover quickly from these stroke symptoms, a TIA may have occurred. All neurological symptoms should serve as a stroke "warning sign" and could indicate a pending, more serious attack. The child should receive prompt evaluation so necessary preventive therapies can be initiated.

WHEN TO CALL THE DOCTOR If a child has any of the symptoms listed above, the parent or caregiver should immediately dial 9-1-1 to seek emergency care. It is important not to wait to see if symptoms subside; a stroke is a medical emergency. Until the paramedics arrive, the parent or caregiver should follow these first aid guidelines:

  • Make sure the child is in a comfortable posture, lying on his or her side, so the airway does not become obstructed by drool or mucus.
  • Talk reassuringly to the child, even if he or she is unconscious.
  • Do not leave the child aloneconstantly observe the child.
  • Cover the child with a blanket or remove clothing as needed to maintain the child's normal body temperature.
  • Do not give the child any medication, including aspirin; medication will be given later as needed.

Diagnosis

In most children, the diagnosis of stroke is delayed by more than 24 hours from the onset of symptoms. This delay is thought to occur because there is a lack of general awareness by physicians and families of cerebrovascular disorders in children. However, early recognition and treatment of a stroke could improve management, reduce the risk of brain damage and permanent disability, help prevent a recurrence, and initiate a proper treatment and rehabilitation program to maximize functional recovery.

The diagnosis of pediatric stroke generally occurs in the emergency room and includes:

  • personal and family medical history
  • review of current medications
  • evaluation of other health problems
  • physical examination
  • brief neurological exam
  • diagnostic tests

The medical history helps the physician evaluate the presence of other conditions or disorders that might have caused the stroke. The child's family medical history is evaluated to determine if there is a history of cardiovascular or neurological diseases that might increase the risk of blood clots.

The brief neurological exam includes a review of the patient's mental status, motor and sensory system, deep tendon reflexes, coordination, and walking pattern (gait). The cranial nerve function also will be evaluated and includes a review of the patient's visual function and eye movement, strength of facial muscles, the gag reflex, tongue and lip movements, ability to smell and taste, hearing, and sensation and movement of the face, head, and neck.

Questions about the child's condition may include:

  • What symptoms occurred?
  • When were the symptoms first noticed?
  • How long did the symptoms last?
  • What functions were affected?

During the physical exam, the child's pulse, blood pressure, and height and weight are checked and recorded.

Diagnostic tests include:

  • Blood tests: Test used to detect the presence of any chemical abnormalities, infection, or blood clotting that may have caused the stroke.
  • Magnetic resonance imaging (MRI) scan: An imaging technique that provides a detailed picture of the brain without the use of x rays. MRI uses a large magnet, radio waves and a computer to produce these images.
  • Computed tomography (CT) scan: An imaging technique that shows the blood vessels in the brain. A CT scan is used to identify the area of the brain affected and to detect signs of swelling.
  • Chest x ray: X rays are used to detect an enlarged heart, vascular abnormalities, or lung problems.
  • Angiogram: An invasive imaging technique used to examine the blood vessels in the brain. An angiogram is only performed if the CT or MRI scans do not show conclusive results.
  • Echocardiogram (echo): A graphic outline of the heart's movement, valves and chambers, used to determine if the stroke was caused by a blood clot traveling from the heart to the brain. Echo is often combined with Doppler ultrasound and color Doppler. During the echo, an ultrasound transducer (hand-held wand placed on the skin of the chest) emits high-frequency sound waves to produce pictures of the heart's valves and chambers.

MRI is more sensitive than CT scanning for the diagnosis of an ischemic stroke within 24 hours. However, the two tests are comparable when used to evaluate the effects of a hemorrhagic stroke.

In rare cases or when carotid artery disease is suspected, additional tests may include a carotid ultrasound or cerebral or carotid angiogram. Other tests to diagnose stroke may include a transcranial Doppler ultrasound and neurosonogram. In a transcranial Doppler ultrasound, sound waves are used to measure blood flow in the vessels of the brain. In a neurosonogram, ultra high frequency sound waves are used to analyze blood flow and possible blockages in the blood vessels in or leading to the brain.

If a pediatric stroke is diagnosed, additional tests may be performed to assess the overall function

  • Electroencephalogram (EEG): Electrodes (small, sticky metal patches attached to the scalp) are connected by wires (leads) to an electroencephalograph machine to chart the brain's continuous electrical activity.
  • Evoked potentials study: Wires attached to the scalp, neck, and limbs are connected to a computer to measure the electrical activity in certain areas of the brain and spinal cord when specific sensory nerve pathways are stimulated. The brain's electrical response to visual, auditory, and sensual stimulation is recorded.

Treatment

Initial treatment depends on the type of stroke. For an ischemic stroke, initial emergent treatment focuses on restoring blood flow to the brain. For a hemorrhagic stroke, the goal of initial treatment is to control the bleeding. Children with a hemorrhagic stroke may be transferred to a center with neurosurgical facilities so the proper treatment, such as decompression or hydrocephalus drainage, can be provided by skilled specialists.

Emergency-room treatment may include: oxygen to ensure the brain is getting the maximum amount, control of body temperature, assessment and treatment of breathing difficulties, intravenous fluids to prevent or treat dehydration , and medications to control blood pressure and prevent blood clotting. Blood transfusions may be used to treat children with sickle cell disease.

Treatment team

Treatment should be provided by a pediatric neurologist and a multi-disciplinary team of specialists that may include a physical therapist, occupational therapist, speech therapist, social worker, and other specialists as needed to meet the child's individual needs.

Medications

Adult stroke patients who receive treatment within three hours after the onset of stroke symptoms may receive a "clot-busting" medication called t-PA. However, the diagnosis of stroke is rarely made within three hours, so the use of this drug in children is uncommon.

Anticoagulant medications, including heparin or warfarin and low-dose aspirin, may be used to reduce the risk of blood clot formation. Although experience with these medications in children suggests they are safe, their use in children remains controversial because of the risk of Reye's syndrome. Sometimes the potential benefits of these medications outweigh the small risk of side effects. Researchers agree that further studies are needed to determine the proper dosage and effectiveness of aspirin and other anticoagulant medications for treating stroke in children.

The most important medication guidelines are: 1) Ensure your child takes all medications exactly as prescribed; 2) Never discontinue any medication without first talking to the child's doctor, even if the medication does not seem to be working or is causing unwanted side effects; and 3) Follow-up with the child's health care provider as recommended to monitor the effects of the medication. Frequent blood tests are required for people taking anticoagulants to evaluate the dosage and effects of the medication.

Other stroke medications that are still being tested in clinical trials include:

  • Citicoline as a treatment for ischemic stroke. Studies have shown both acute and long-term neuroprotective properties of citicoline in animal models of stroke and in several human clinical trials.
  • Epoetin, a synthetic version of human erythropoietin, as a treatment for ischemic stroke. Epoetin aids the body in producing red blood cells and is currently used to treat anemia associated with kidney disease or caused by some drugs.
  • Early administration of magnesium to serve as a potential neuroprotective agent. Studies have shown neuroprotectant properties of magnesium sulfate in animal models of stroke, and improved outcomes following magnesium sulfate treatment in humans have been observed following small pilot studies.

Rehabilitation

After the child's condition has stabilized, rehabilitation is initiated. Rehabilitation includes physical, occupational, and speech therapy. Therapy is usually initiated as soon as possible after a stroke and is often the most intense in the early stages of recovery. Clinicians should work with the child and the parents or caregivers to develop an individual treatment plan. Specific treatment goals will vary from one child to the next but will focus on restoring maximum function and independence, helping the child return to normal activities, and improving the child's quality of life. The child's progress after rehabilitation will depend upon which area of the brain was affected, the cause of stroke, the extent of injury, and the presence of other medical conditions.

Physical therapy includes stretching exercises, muscle group strengthening exercises, and range of motion exercises to preserve flexibility and range of motion. Exercises should be practiced daily, as recommended by the physical therapist. A physical therapist can instruct the patient on proper posture guidelines to maintain proper alignment of the hips and back. Balancing rest and exercise is also important.

Occupational therapy may include splints, casts, or braces on the affected arm or leg to enable proper limb positioning, prevent joint stiffness, and maintain flexibility and range of motion. An occupational therapist can recommend assistive equipment and devices to help the child with activities of daily living, such as bathing, dressing, and eating. If a walker or wheelchair are needed, an occupational therapist can provide specific instructions.

Physical and occupational therapists can provide guidelines on how to adapt the child's home and school environments to ensure safety and comfort.

Speech therapy will focus on the child's specific needs which may include any or all aspects of language use, such as speaking, reading, writing, and understanding the spoken word. Speech and language problems (aphasia) usually occur when a stroke affects the right side of the body.

Behavioral problems and learning disabilities, such as difficulties with attention or concentration, may become apparent when the child goes to school, so specific treatments and educational assistance may be needed to address these problems. A formal assessment can help parents identify potential behavioral and learning problems.

Surgery

The need for surgical treatment for pediatric stroke will depend on a number of factors, including the type of stroke, extent of damage from stroke, the child's age, and potential benefits and risks. Sometimes urgent surgery is necessary soon after the child is admitted to the emergency room to remove a blood clot and restore oxygen flow to the brain tissue.

Treatment options for hemorrhagic stroke may include surgery, sterotactic radiotherapy, or interventional neuroradiology to treat the underlying aneurysm or arteriovenous malformation.

There are several surgical procedures to repair an aneurysm that may have caused a hemorrhagic stroke. A clip may be placed across the neck of the aneurysm (like a clip at the end of a balloon) to stop the bleeding. A newer approach is to thread a long, thin tube through the artery that leads to the aneurysm. Then a tiny coil is fed through the tube into the aneurysm "balloon" to fill the space and seal off the bleeding.

An interventional procedure called carotid angioplasty may be performed to treat a blockage or blockages in the carotid arteries. During the procedure, a tiny balloon at the end of a long, thin tube (called a catheter) is pushed through the artery to the blockage. When the balloon is inflated, it opens the artery. In addition, a mesh tube (called a stent) may be placed inside the artery to help hold it open.

Carotid endarterectomy is a surgical procedure performed to remove a blockage from the carotid artery. During the operation, the surgeon scrapes away plaque from the wall of the artery so blood can flow freely through the artery to the brain.

Intracranial bypass surgery is a surgical procedure performed to restore blood flow around a blocked blood vessel in the brain. During the surgery, a healthy blood vessel, on the outside of the scalp, is re-routed to the part of the brain that is not getting enough blood flow. This new blood vessel bypasses the blocked vessel and provides an additional blood supply to areas of the brain that were deprived of blood. When blood flow is restored, the brain works normally, and the symptoms disappear. This procedure is not as common as the other surgical treatments listed above to treat pediatric stroke but it may be used to treat recurrent TIAs.

Alternative treatment

Alternative and complementary therapies include approaches that are considered to be outside the mainstream of traditional health care.

Techniques that induce relaxation and reduce stress, such as yoga , Tai Chi, meditation, guided imagery, and relaxation training, may be helpful in controlling blood pressure. Acupuncture and biofeedback training also may help induce relaxation. Before learning or practicing any particular technique, it is important for the parent/caregiver and child to learn about the therapy, its safety and effectiveness, potential side effects, and the expertise and qualifications of the practitioner. Although some practices are beneficial, others may be harmful to certain patients.

Alternative treatments should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these techniques and treatments with the child's doctor to determine the remedies that may be beneficial for the child.

Nutritional concerns

Dietary guidelines are individualized, based on the child's age, diagnosis, overall health, and level of functioning. Specific nutritional problems, such as swallowing or feeding difficulties, may be a concern in some patients and should be managed by a team of specialists including a speech therapist. Early identification, treatment, and correction of specific feeding problems will improve the health and nutritional status of the child.

A child's self-feeding skills can impact his or her health outcome. One study indicated that 90 percent of children with good to fair motor and feeding skills reached adulthood. In contrast, a lack of self-feeding skills was associated with a six-fold increase in mortality (rate of death).

Maintaining a healthy weight is important to prevent the development of chronic diseases such as diabetes, high blood pressure (hypertension ), and heart disease.

Tube feedings may be required in some patients with failure to thrive , aspiration pneumonia , difficulty swallowing, or an inability to ingest adequate calories orally to maintain nutritional status or promote growth.

A well-balanced and carefully planned diet will help maintain general good health for children who have suffered a stroke. In general, children should follow the same low-fat, high fiber diet that is recommended for the general population.

In children older than age two, the following low-fat dietary guidelines are recommended:

  • Total fat intake should comprise 30 percent or less of total calories consumed per day.
  • Calories consumed as saturated fat should equal no more than 8-10 percent of total calories consumed per day.
  • Total cholesterol intake should be less than 300 mg/dl per day.

If the child has high blood pressure, the DASH diet is recommended. The "Dietary Approaches to Stop Hypertension (DASH)" study, sponsored by the National Institutes of Health (NIH), showed that elevated blood pressures were reduced by an eating plan that emphasized fruits, vegetables, and low-fat dairy foods and was low in saturated fat, total fat, and cholesterol. The DASH diet includes whole grains, poultry, fish, and nuts. Fats, red meats, sodium, sweets, and sugar-sweetened beverages are limited. Sodium should also be reduced to no more than 1,500 milligrams per day.

Prognosis

Cerebrovascular disorders are among the top 10 causes of death in children, with rates highest in the first year of life. From 1979 to 1998 in the United States, childhood mortality from stroke declined sharply, by 58 percent, with reductions in all major subtypes: ischemic stroke decreased by 19 percent, subarachnoid hemorrhage by 79 percent, and intracerebral hemorrhage by 54 percent.

Some children survive a pediatric stroke with no life-long consequences. In other children, long-term complications of stroke may develop right away or within months to years after a stroke. According to a 2000 study published in the Journal of Child Neurology, the outcome of childhood stroke was a moderate or severe deficit in 42 percent of cases. Adverse outcomes after childhood strokeincluding death in 10 percent, recurrence in 20 percent, and neurological deficits in two-thirds of survivorscan be reduced with available stroke treatments.

When a stroke affects a child whose brain is still developing, it is thought that the developing brain may be able to compensate for the functions that were lost as a result of a stroke.

Recovery from stroke is different with each child. Overall, the degree of permanent disability after a stroke is less in children than in adults. Speech and language problems usually improve rapidly in the first year after a stroke. Children may only have minor delays in the development of coordinated movement or in cognitive functioning. Almost all children recover the ability to walk independently after a stroke, unless there is another condition that causes disability. Recovery of function in the affected arm and hand is usually the most significant movement problem after a stroke. Most children who suffer from a stroke can expect to lead independent lives as adults.

Prevention

Despite current treatment, one out of 10 children with ischemic stroke will have a recurrence within five years. Although there is a high risk of repeat strokes in patients with sickle cell anemia, the risk can be reduced with regular blood transfusions. If no cause of the stroke was identified, the risk of a recurrence is low. If a cause was identified, the underlying condition should be treated, and anticoagulant or low-dose aspirin therapy may be initiated, depending on the child's diagnosis.

There is no screening for stroke, but screening exists for many of its risk factors. To prevent stroke, risk factors should be treated and managed by the child's primary care doctor or specialist. The doctor can advise if specific preventive treatment is needed.

Management of high cholesterolespecially high LDL (low-density lipoprotein) levelshigh blood pressure and diabetes can help reduce the risk of a stroke.

Nutritional concerns

An adequate intake of folic acid (vitamin B9) has been linked to the prevention of stroke and heart disease by lowering homocysteine, an amino acid related to the early development of cardiovascular disease when high levels are present in the blood. Dietary sources of folic acid include: vegetables, especially green vegetables; potatoes; cereal and cereal products; fruits; and organ meats (liver or kidney). It is best to eat fresh fruits and vegetables whenever possible to get the most vitamins . Recommended daily intake in micrograms (mcg) for folic acid supplements (oral tablets) include: 25100 mcg in newborns to age three; 75400 mcg in children aged four to six; 100-400 mcg in children aged seven to 10; and 150400 mcg in children aged 11 and above.

Vitamin K is an important nutrient needed to regulate normal blood clotting. A diet deficient in vitamin K can cause prolonged blood-clotting time and easy bleeding and bruising. Vitamin K is found in: alfalfa, asparagus, broccoli, Brussels sprouts, cabbage cheddar cheese, green tea, green leafy lettuce, liver, seaweed, spinach, and turnip greens. Recommended daily intake for vitamin K supplements (for patients not on anticoagulant therapy) include: 10 mcg in newborns to age three; 20 mcg in children aged four to six; 30 mcg in children aged seven to 14; 65 mcg in boys and 55 mcg in girls aged 1518; 7080 mcg for males over age 18 and 6065 mcg for females over age 18. If the patient is taking anticoagulant medications, vitamin K supplements are not recommended, and foods high in vitamin K are limited, since they counteract the action of the medication.

Vitamin E and beta carotene supplements were once thought to help decrease the risk of stroke and prevent the development of heart disease, but newer studies disprove their effectiveness. Researchers at The Cleveland Clinic Heart Center performed a meta-analysis of seven large randomized trials of vitamin E (given alone or in combination with other antioxidants) and eight of beta carotene. All trials included 1,000 or more patients and follow-up ranged from 1.4 to 12 years. The doses of vitamin E given in these trials ranged from 50800 international units (IU) and 1550 milligrams (mg) for beta carotene. The meta-analysis reviewed the effect of these antioxidants on death from cardiovascular disease or from any other cause ("all-cause mortality").

Their findings, published in the June, 2003 issue of The Lancet journal, do not support the continued use of vitamin E supplementation nor the inclusion of vitamin E in further studies. Regardless of the dosage given or the patient population, Vitamin E did not provide any benefit in lowering mortality compared to control treatments, and it did not significantly decrease the risk of cardiovascular death or stroke (cerebrovascular accident). In addition, they recommend that vitamin supplements containing beta carotene be "actively discouraged" because of the small but statistically significant increased risk of death. Researchers discourage further study of beta carotene because of the mortality risk.

Even though studies have demonstrated that vitamin E and beta carotene supplements do not reduce stroke risk, foods rich in antioxidants are still encouraged because they also contain beneficial nutrients such as flavonoids and lycopenes that are not usually included in standard oral vitamin supplements. A diet rich in antioxidant-containing foods, such as fruits, vegetables and whole grains, is linked to a reduced risk of cardiovascular disease.

Dietary supplements should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these nutrition supplements with the child's doctor to determine the remedies that may be beneficial for the child.

Parental concerns

It is common for a child to feel sad or depressed after a stroke. These emotions may be the result of not knowing what to expect or not being able to do simple tasks without becoming overly tired. Temporary feelings of sadness are normal, and should gradually go away within a few weeks, as the child starts a rehabilitation program and returns to some of his or her normal routines and activities.

When a depressed mood is severe and accompanied by other symptoms that persist every day for two or more weeks, the parent should ask for a referral to a mental health professional who can help the child cope and recover. There are many treatments for depression. A healthy lifestyle including regular exercise, proper sleep , a well-balanced diet, as well as relaxation and stress management techniques can help manage depression. Major depressive disorder may be treated with antidepressants , psychotherapy (supportive counseling or "talk therapy"), or a combination of both.

Regular follow-up visits with the child's health care provider will help identify and manage risk factors and other medical conditions. If the child has a known medical condition that increases the risk of stroke, it is important for parents and caregivers to learn the warning signs and symptoms of stroke in children and infants. If the child experiences any unexpected neurological problem, the parent should have the child evaluated by a physician. Lastly, it is important for parents to carefully follow the child's treatment plan, including following the medication schedule exactly as prescribed.

Resources

BOOKS

Burkman, Kip. The Stroke Recovery Book: A Guide for Patients and Families. Nebraska: Addicus Books, Inc., May, 1998.

Senelick, Richard C., Peter W. Rossi, and Karla Dougherty. Living with Stroke: A Guide For Families: Help and New Hope for All Those Touched by Stroke. New York: McGraw-Hill/Contemporary Books, June, 1999.

Zimmer, Judith and John P. Cooke. The Cardiovascular Cure: How to Strengthen Your Self-Defense Against Heart Attack and Stroke. New York: Broadway Books, August, 2002.

PERIODICALS

Abram, Harry S., MD. "Childhood Strokes: Evaluation and Treatment." Duval County Medical Society. www.dchmsonline.org/jax-medicine/1998journals/november1998/childhoodstrokes.htm.

deVeber, G., ES Roach, AR Riela, and M. Wiznitzer. "Stroke in Children: Recognition, Treatment, and Future Directions." Seminars in Pediatric Neurology. 7:4 (December, 2000): 309-317.

deVeber, G., ES Roach, AR Riela, and M. Wiznitzer. "Recognition and Treatment of Stroke in Children." Child Neurology Society Ad Hoc Committee on Stroke in Children. July, 2001.

Kirkham, FJ. "Stroke in Childhood." Archives of Disease in Childhood. 81 (July, 1999): 85-89.

Nicolaides, P. and R.E. Appleton. "Stroke in Children." Developmental Medicine and Child Neurology. 38:2 (February, 1996): 172-180.

ORGANIZATIONS

American Stroke Foundation. 11902 Lowell, Overland Park, KS 66213. (913) 649-1776. <http://www.americanstroke.org>.

KEY TERMS

Activities of daily living (ADL) The activities performed during the course of a normal day, for example, eating, bathing, dressing, toileting, etc.

Aneurysm A weakened area in the wall of a blood vessel which causes an outpouching or bulge. Aneurysms may be fatal if these weak areas burst, resulting in uncontrollable bleeding.

Anoxia Lack of oxygen.

Antibody A special protein made by the body's immune system as a defense against foreign material (bacteria, viruses, etc.) that enters the body. It is uniquely designed to attack and neutralize the specific antigen that triggered the immune response.

Antiphospholipid antibody syndrome An immune disorder that occurs when the body recognizes phospholipids (part of a cell's membrane) as foreign and produces abnormal antibodies against them. This syndrome is associated with abnormal blood clotting, low blood platelet counts, and migraine headaches.

Aorta The main artery located above the heart that pumps oxygenated blood out into the body. The aorta is the largest artery in the body.

Aortic valve The valve between the heart's left ventricle and ascending aorta that prevents regurgitation of blood back into the left ventricle.

Aortic valve stenosis Narrowing of the aortic valve.

Aphasia The loss of the ability to speak, or to understand written or spoken language. A person who cannot speak or understand language is said to be aphasic.

Arteriosclerosis A chronic condition characterized by thickening, loss of leasticity, and hardening of the arteries and the build-up of plaque on the arterial walls. Arteriosclerosis can slow or impair blood circulation. It includes atherosclerosis, but the two terms are often used synonymously.

Artery A blood vessel that carries blood away from the heart to the cells, tissues, and organs of the body.

Atrial Referring to the upper chambers of the heart.

Atrial fibrillation A type of heart arrhythmia in which the upper chamber of the heart quivers instead of pumping in an organized way. In this condition, the upper chambers (atria) of the heart do not completely empty when the heart beats, which can allow blood clots to form.

Atrial septal defect An opening between the right and left atria (upper chambers) of the heart.

Cardiologist A physician who specializes in diagnosing and treating heart diseases.

Central nervous system Part of the nervous system consisting of the brain, cranial nerves, and spinal cord. The brain is the center of higher processes, such as thought and emotion and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system, that is the nerves present in the rest of body.

Cerebrospinal fluid The clear, normally colorless fluid that fills the brain cavities (ventricles), the subarachnoid space around the brain, and the spinal cord and acts as a shock absorber.

Decompression A decrease in pressure from the surrounding water that occurs with decreasing diving depth.

Dysphagia Difficulty in swallowing.

Echocardiogram A record of the internal structures of the heart obtained from beams of ultrasonic waves directed through the wall of the chest.

Electrocardiagram (ECG, EKG) A record of the electrical activity of the heart, with each wave being labeled as P, Q, R, S, and T waves. It is often used in the diagnosis of cases of abnormal cardiac rhythm and myocardial damage.

Embolus Plural, emboli. An embolus is something that blocks the blood flow in a blood vessel. It may be a gas bubble, a blood clot, a fat globule, a mass of bacteria, or other foreign body that forms somewhere else and travels through the circulatory system until it gets stuck.

Encephalitis Inflammation of the brain, usually caused by a virus. The inflammation may interfere with normal brain function and may cause seizures, sleepiness, confusion, personality changes, weakness in one or more parts of the body, and even coma.

Graft A transplanted organ or other tissue.

Heart attack Damage that occurs to the heart when one of the coronary arteries becomes narrowed or blocked.

Hemiparesis Weakness on one side of the body.

Hemiplegia Paralysis of one side of the body.

Hydrocephalus An abnormal accumulation of cerebrospinal fluid within the brain. This accumulation can be harmful by pressing on brain structures, and damaging them.

Hypercoagulable states Also called thromboembolic state or thrombophilia. A condition characterized by excess blood clotting.

Hypertension Abnormally high arterial blood pressure, which if left untreated can lead to heart disease and stroke.

Intracerebral hemorrhage A cause of some strokes in which vessels within the brain begin bleeding.

Ischemia A decrease in the blood supply to an area of the body caused by obstruction or constriction of blood vessels.

Mitral valve stenosis Narrowing of the mitral valve.

Neurologist A doctor who specializes in disorders of the nervous system, including the brain, spinal cord, and nerves.

Neurosurgeon Physician who performs surgery on the nervous system.

Occupational therapist A healthcare provider who specializes in adapting the physical environment to meet a patient's needs. An occupational therapist also assists patients and caregivers with activities of daily living and provide instructions on wheelchair use or other adaptive equipment.

Patent ductus arteriosus A congenital defect in which the temporary blood vessel connecting the left pulmonary artery to the aorta in the fetus doesn't close after birth.

Patent foramen ovale (PFO) A congenital heart defect characterized by an open flap that remains between the two upper chambers of the heart (the left and right atria). This opening can allow a blood clot from one part of the body to travel through the flap and up to the brain, causing a stroke.

Physiatrist A physician who specializes in physical medicine and rehabilitation.

Physical therapist A healthcare provider who teaches patients how to perform therapeutic exercises to maintain maximum mobility and range of motion.

Reye's syndrome A serious, life-threatening illness in children, usually developing after a bout of flu or chickenpox, and often associated with the use of aspirin. Symptoms include uncontrollable vomiting, often with lethargy, memory loss, disorientation, or delirium. Swelling of the brain may cause seizures, coma, and in severe cases, death.

Stent A slender hollow catheter or rod placed within a vessel or duct to provide support or to keep it open.

Subarachnoid hemorrhage A collection of blood in the subarachnoid space, the space between the arachnoid and pia mater membranes that surround the brain. This space is normally filled with cerebrospinal fluid. A subarachnoid hemorrhage can lead to stroke, seizures, permanent brain damage, and other complications.

Unilateral neglect Also called one-sided neglect. A side effect of stroke in which the stroke survivor ignores or forgets the weaker side of the body caused by the stroke.

Vein A blood vessel that returns blood to the heart from the body. All the veins from the body converge into two major veins that lead to the right atrium of the heart. These veins are the superior vena cava and the inferior vena cava. The pulmonary vein carries the blood from the right ventricle of the heart into the lungs.

Ventricle septal defect A hole in the wall (septum) between the lower chambers of the heart.

Ventricles The lower pumping chambers of the heart. The ventricles push blood to the lungs and the rest of the body.

Ventricles of the brain The spaces within the brain where cerebrospinal fluid is made.

American Stroke Association, A Division of American Heart Association, 7272 Greenville Ave., Dallas, TX 75231. (888) 4-STROKE (787653). E-mail: strokeassociation@heart.org. <http://www.strokeassociation.org>.

Children's Hemiplegia and Stroke Association. 4101 W. Green Oaks, Ste. 305, PMB 149, Arlington, TX 76016. (817) 492-4325. E-mail: info@chasa.org. <http://www.chasa.org>.

National Heart, Lung and Blood Institute. National Institutes of Health, Building 1, 1 Center Dr., Bethesda, MD 20892. E-mail: NHLBIinfo@rover.nhlbi. <http://www.nhlbi.nih.gov>.

National Institute on Disability and Rehabilitation Research, Office of Special Education and Rehabilitative Services, U.S. Department of Education, 400 Maryland Ave. S.W., Washington, DC 20202-7100. (202) 245-7640. <http://www.ed.gov/about/offices/list/osers/nidrr/>.

National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health. P.O. Box 5801, Bethesda, MD 20824. (800) 352-9424 or (301) 496-5751. <http://www.ninds.nih.gov/about_ninds/>.

National Rehabilitation Information Center (NARIC).4200 Forbes Blvd., Ste. 202, Lanham, MD 20700. (800) 346-2742 or (301) 459-5900. <http://www.naric.com>.

National Stroke Association. 9707 E. Easter Ln., Englewood, CO 80112-3747. (800) STROKES (787-6537) or (303) 649-9299. <http://www.stroke.org>.

Stroke Clubs International. 805 12th St. Galveston, TX 77550. (409) 762-1022 attn. Ellis Williamson. E-mail: strokeclub@aol.com.

WEB SITES

The Brain Attack Coalition. <www.stroke-site.org>

The Brain Matters, American Academy of Neurology Foundation. <www.thebrainmatters.org>

Different StrokesA Charity for Younger Stroke Survivors. <www.differentstrokes.co.uk/>

HeartCenterOnline. <www.heartcenteronline.com>

HemiHelpInformation and Support for Children and Young People with Hemiplegia. <www.hemihelp.org.uk>

Pediatric Stroke Network. <www.pediatricstrokenetwork.com>

Angela M. Costello

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Costello, Angela. "Stroke." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

Costello, Angela. "Stroke." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1G2-3447200549.html

Costello, Angela. "Stroke." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3447200549.html

Stroke

STROKE

A stroke is defined as a sudden loss of brain function due to a blocked or burst blood vessel. There are two classifications of stroke, ischemic and hemorrhagic. Ischemic strokes account for approximately 80 percent of all strokes and result from blockage of the blood supply to the brain. Hemorrhagic strokes account for the remaining 20 percent of all strokes and result from bleeding in the brain. When the bleeding is in the brain itself, it is an intracerebral hemorrhage; if the bleeding occurs between the brain and the skull, it is a subarachnoid hemorrhage.

The brain needs a continuous and fresh supply of oxygen and glucose to function. Oxygen and glucose are carried in the blood and reach the brain through four arteries arranged in two systems. The carotid arteries in the neck carry most of the blood to the brain. The vertebral arteries in the spine join at the base of the brain to form the basilar artery. They supply blood to the core of the brain, which deals with vital functions. Any interruption of blood supply to the brain interferes with the brains ability to function.

Causes of ischemic stroke

Ischemic stroke occurs when the blood supply to the brain is blocked. The most common cause of blockage is blood clots. Blood clots can form almost anywhere in the body, dislodge, and travel through the arteries eventually lodging and diminishing or cutting off blood flow. They originate most commonly in the heart. Blood clots form in the heart for many reasons, including birth defects, malfunctioning or damaged heart valves, and an irregular heartbeat (atrial fibrillation).

Damaged arteries represent another leading cause of ischemic stroke. There are three main causes of damage to the arteries. Atherosclerosis can occur in any artery in the body but causes stroke most often when it is found in the neck arteries. As people age, small streaks of fat settle in the walls of the arteries. These streaks can grow into plaque that can trap cells in the blood platelets that start clotting. The fatty deposits build up and can eventually fester and crack, forming clots that either close off a neck artery or wash up into the brain, resulting in a stroke.

Accidental damage to the neck arteries can also cause stroke. An artery has three layers, and any sudden twist of the neck or direct trauma to the neck can cause the arterial layers to shear apart (dissection) and either close the vessel or create clots that will cause blockage that results in stroke.

In people who suffer from high blood pressure, their brain blood vessels can become thick, stiff, and brittle. Because there is less room for blood to flow and the vessels are not flexible enough to accommodate increased blood pressure, they can either close off completely or rupture. Diabetes can also weaken the small blood vessels of the brain.

Blood abnormalities can be a potential source of stroke. Abnormalities in the blood can cause clotting, bleeding, or both.

Blood supply is essential to the health and operation of the brain. The areas of the brain that do not receive enough blood or no blood at all will die, resulting in dead tissue (infarct) and loss of brain function.

Causes of hemorrhagic stroke

Hemorrhagic stroke occurs when there is bleeding within the brain. It is less common than ischemic stroke but is often more severe.

There are three main causes for bleeding in the brain (intracerebral hemorrhages). High blood pressure can weaken the arteries so that they eventually rupture and cause bleeding. Blood can become too thin as a result of blood thinning medication (anticoagulants). And as people age, they tend to have abnormal deposits of amyloid protein (amyloid angiopathy) in blood vessels, which can lead to bleeding in the brain.

Bleeding around the brain, known as subarachnoid hemorrhage, most often results from a burst aneurysm. An aneurysm develops on a weakened part of a blood vessel and resembles a pouch. A bursting aneurysm is usually signaled by a sudden, unusual, and severe headache. Some have suggested that it feels like being struck on the back of the head by a baseball bat. Other symptoms associated with a burst aneurysm may include neck stiffness and double vision. Not all aneurysms are dangerous or require surgery, but if an aneurysm ruptures it is quite serious.

The second most common cause of subarachnoid hemorrhages is the rupture of a cluster of abnormal blood vessels in the brain, the arteriovenous malformation.

Areas of the brain and effects of damage

The brainstem is considered to be an extension of the spinal cord and is nestled below the larger part of the brain. It is responsible for critical automatic functions of the body, such as breathing, maintaining blood pressure and heart rate, swallowing, chewing, eye movements, and quick reflexes. It is also the site of major passageways to and from the upper brain and the rest of the body. A stroke that originates in the brain-stem is usually fatal. Fortunately, many strokes involve only part of the brainstem. Double vision, imbalance, trouble swallowing, and weakness or numbness of the face or limbs may result, depending on the part of the brain stem that is affected.

At the back of the brainstem is the little brain or cerebellum. The cerebellum coordinates movements and balance, and stores the memory of habitual muscle movements, such as the pattern of the muscle movement used to swing a baseball bat. A stroke that hits the cerebellum can cause unsteadiness, lack of coordination, and awkwardness of the limbs.

Some consider the cerebrum to be the most important part of the brain. It is the most highly developed area of the brain and is what defines people as humans. The cerebrum receives information from all parts of the body, processes the information, and reacts almost instantaneously. A stroke in the cerebrum can affect so many aspects of day-to-day living. To better understand how a stroke survivor can be affected, one should look at all of the parts of the cerebrum.

The cerebrum is divided into two hemispheres, right and left, each controlling the side of the body opposite to it. Each hemisphere controls certain functions, but the two are connected by nerve fibers that allow them to work together or compensate for one another.

The right hemisphere recognizes shapes, angles, proportions, and visual patterns such as peoples faces. The right hemisphere is responsible for emotions, musicality, creativity, and imagination. It also controls a persons spatial self-awareness. For example, some people who have had their right hemisphere damaged by a stroke no longer feel that their body is their own, and some who are paralyzed on the left side of their body may not recognize their own left hand.

The left hemisphere controls speech, logic, analytical thought, problem solving, language, and movements on the right side of the body. Stroke in the left hemisphere may result in paralysis of the right side of the body and difficulty with communicating and understanding.

The hemispheres are further divided into four lobes. The occipital lobe is the vision center, and a person can be left blind even if the eyes are not damaged when the stroke hits here.

The temporal lobe forms and stores memories, and unless both the right and left temporal lobes are affected, memory loss is not likely to be permanent. Hearing and understanding speech are other functions of the temporal lobe. Wernickes area spreads from the temporal lobe into the neighboring parietal lobe, and a stroke here impairs ability to understand language but almost never affects hearing.

The parietal lobes influence the sense of space, perspective, and interpretation. They also contain a strip of sensory cortex that receives and interprets information from the body. The motor cortex is located in front of the sensory cortex, and if it is damaged, paralysis of the face, arm, or leg can occur.

Behavior, anticipation, emotion, thinking, motor function, planning, and speech expression are controlled in the most highly developed part of the brain, the frontal lobes. The frontal lobes influence much of what is considered to be an individuals personality, and as a result the ability to test the damage to frontal lobes and the degree of impairment is difficult. Stroke can change personality and thinking. A patient may appear to act out of character and the ability to determine what is socially appropriate and what is not may be impaired. Increased difficulty with completing tasks can also be seen. This can be a result of the patients forgetting sequences of steps to finish something or inability to send the message to the appropriate muscles to complete a task.

The human brain is a very complicated organ, and stroke damage can be devastating. However, the prognosis is not always so bleak. The brains ability to have other parts of it assume lost function and its ability to adapt are just being discovered, bringing greater hopes of recovery for the future.

Warning symptoms

Typically, many think of stroke as a disease affecting only elderly persons, particularly men. This is not the case at all. Stoke can strike an individual of any age, race, or gender. As people age, the risk for stroke increases, but the warning signs of stroke are something that everyone should know.

A person who suddenly experiences one or more of the following symptoms may be having a stroke: (1) weakness or numbness of the face, arm, or leg; (2) loss or slurring of speech; (3) loss or blurring of vision; (4) a sensation of motion (vertigo); (5) difficulty with balance; (6) unusual or severe headache. The sudden onset of any one or more of these symptoms requires immediate action. Stroke is a medical emergency and must be treated accordingly. The sooner medical help is obtained the better the chances for surviving a stroke.

Symptoms of stroke usually occur within seconds. If the symptoms come on quickly and disappear just as quickly, a doctor should be contacted. If the symptoms still persist after fifteen minutes, the person should be taken to the emergency department of the nearest hospital where a specialist can assess the symptoms.

Symptoms of migraine headaches can sometimes be confused with symptoms of stroke. The key difference in the onset of symptoms lies in the timing. Migraine symptoms usually progress over minutes, whereas stroke symptoms occur in mere seconds. Timing is a critical factor in assessing stroke.

Transient ischemic attacks, more commonly known as TIAs, are a crucial warning sign of an impending stroke. The symptoms of a TIA are exactly the same as of a stroke; the only difference is that the symptoms usually disappear within fifteen minutes. Just because a symptom goes away does not mean that the person is not at risk. TIAs can indicate that the brain is having difficulty receiving the required amount of blood and the person is therefore more likely to have a stroke. Immediate diagnosis of symptoms can drastically reduce the chance of a stroke. Having a TIA does not mean a person will definitely have a stroke, but it is a key indicator that medical attention is needed.

Heart attack can be associated with stroke. The term brain attack was invented to advise people that the stroke is serious and that urgent medical attention is required. The most common cause of heart attack is also the most common cause of stroke. Hardening of the arteries (atherosclerosis) impedes blood flow and can create blood clots, leading to either heart attack or stroke. People who suffer a stroke may also suffer a heart attack, and vice versa. One reason for this may be that people who have either a stroke or a heart attack, have common risk factors for atherosclerosis, such as family history, high blood pressure, smoking, diabetes, high cholesterol, or homocystenemia.

There are three major differences between heart attack and stroke. First, there are many more causes of stroke than of heart attack. Second, heart attack is more easily diagnosed by either an electrocardiogram or a cardiac enzyme test, whereas images of the brain may not show any changes in the brain until hours after the onset of stroke symptoms. As a result, the diagnosis of stroke relies heavily on clinical judgment.

Last, chest pains (angina) are a clear indication of an impending heart attack. The greater the chest pain, the greater the problem. This is not the case with stroke. Whether a person has one TIA or several, the risk of stroke is the same. Preexisting conditions and risk factors contribute more to the chance of stroke than does how often TIAs occur.

Some other medical conditions can mimic stroke; for instance, the shearing of the artery within the skull or a brain tumor can create symptoms that may at first appear to be those of a stroke. Clinical diagnosis by a physician is the only way to determine if a person has had a stroke.

Diagnosis

As more knowledge is gained about the brain, the prognosis for stroke survivors becomes better. The clinical diagnosis of stroke is an essential part of the treatment process. When a patient arrives at the hospital, the first thing the doctor will do is assess his or her condition. A primary care doctor may be the first doctor one sees, but once a problem with the brain or nervous system is identified a specialist will be called. Neurologists are specialists who diagnose and treat conditions of the brain, but they do not perform surgery. Neurosurgeons perform surgery on the brain and other parts of the nervous system. Other medical specialists may be consulted if the problem involves their area of expertise.

After taking a verbal history, the physician conducts a physical exam. The physician may begin by evaluating muscle strength, reflexes, coordination, balance, capacity to hear, see, smell, and feel, and ability to speak. On the basis of physicians findings, other diagnostic tests may be ordered.

An image of the brain is important in diagnosing a stroke. The physician is looking to see if there is blood on the brain, and if so, where it is. The physician is also trying to see if there is dead tissue (infarct) in the brain, and, if there is, to confirm that this is the result of a stroke (and not something that mimics stroke). Two main ways to get an image of the brain are computerized tomography scan (CT scan) and magnetic resonance imaging (MRI). During the CT scan, a painless procedure, the patients head is placed in a device that looks like a big salon hair dryer. The patient simply lies back and relaxes while X-rays are beamed to reveal the structure of the brain. The MRI may look more intimidating than the CT scan because the patient is put on a bed in a large machine, but it too, is a painless procedure. MRI uses radio frequencies to image the brain and the blood vessels in the head and in the neck. Because technology for the MRI is increasing at a rapid rate, and it is providing more information, it is becoming the diagnostic method of choice.

Ultrasonography has two uses: (1) to measure the speed of blood flow, which helps to determine where there are blockages in arteries; and (2) to produce an image of the blood vessel. The carotid Doppler test is done by moving a device up and down the neck to see if there is a narrowing of the arteries, and a transcranial Doppler test is an ultrasound technique that gives information about the blood flow in the main arteries of the brain.

Imaging of the brain can usually detect the presence of blood, but in some circumstances a spinal puncture, or spinal tap, will be performed to rule out the possibility. The procedure involves taking a small needle, inserting it between the vertebrae in the back, and taking a sample of cerebrospinal fluid to analyze.

Echocardiograms and electrocardiograms are the two types of tests used to detect any abnormalities in the heart that could have caused a stroke. In an echocardiogram, ultrasound creates an image of the heart from which the doctor can see if any blood clots are in pockets of the heart and if the valves of the heart are normal or abnormal. The electrocardiogram maps the heartbeat, making it possible to detect irregular heartbeats, insufficient blood supply, and damaged parts of the heart. Analyzing the heart is important because the heart can be a source for blood clots that break away and reach the brain.

Blood tests are generally done to identify problems that could complicate stroke. Depending on the patients medical history, liver and kidney tests may also be done to detect damage. All of these tests and procedures play a part in the physicians diagnosis.

Treating acute stroke

Stroke patients can be treated in many different settings, but the ideal place for treatment is a stroke unit, where the doctors, nurses, and therapists work together as a specialized unit. When a stroke patient arrives at the hospital, overall medical treatment includes maintaining blood pressure, reducing elevated temperature, and normalizing blood glucose levels. Specific measures performed by the stroke team include attempting to reopen closed blood vessels, protecting the brain, and preventing complications.

Maintaining blood pressure of the patient is important because after stroke, the brain may be unable to control its own blood supply (autoregulation). Blood supply depends on blood pressure, and if the blood pressure is not high enough to pump blood to the damaged area, brain cells will die. To prevent further damage to the brain after stroke, the medical team makes sure that blood pressure is maintained by measuring and medicating if necessary.

Temperature is another factor when treating a stroke patient. An increase in body temperature of even one degree centigrade will double the risk of death or disability in a stroke patient. In addition, patients with a high level of blood glucose at the time of a stroke are less likely to recover; therefore, reducing blood glucose in the acute situation benefits the patient.

The most common cause of stroke is the closing off of a blood vessel to the brain. Some studies have shown that giving the patient a clot-busting (thrombolytic) drug may reopen the closed blood vessels to the head. Thrombolytic drugs are effective only if given early in the onset of stroke and also carry a great risk of causing more bleeding to the head, thus causing more damage and possibly death. The drug in this classification that has been receiving much attention is tissue plasminogen activator (t-PA). It has been used with success in the treatment of heart attacks and is currently being used in treating stroke. The side effect of bleeding to the head may result in death, so it is important that thrombolytic drugs be researched and tested in centers where there are experts in stroke and facilities to deal with the possible consequence of bleeding into the head. With time and caution, thrombolytic treatment may play a more important role in the treatment of acute stroke.

Another type of drug works to protect the brain after stroke. In laboratory studies these drugs have protected the brain when blood deprivation occurred. They are now being tested in clinical studies.

Brain cell repair is the future of recovery after stroke. More is being learned about how the brain repairs injury and the potential of injecting engineered cells to help healing. It may be the case that a combination of drugs that open the blood vessels to the brain protect the brain from breakdown, and speed up the repair of the brain will be the ideal treatment of the future.

Surgery is not used in the acute treatment phase unless a blood clot is pressing on one of the vital parts of the brain or if an aneurysm has ruptured and there is bleeding around the brain (subarachnoid hemorrhage). Timing is important when dealing with a ruptured aneurysm. There are two approaches considered by the neurosurgeon: (1) to operate before the brain vessels go into spasm (vasospasm), or (2) to wait a for the vasospasm to disappear and then operate. Operating early has a higher rate of complication, but waiting allows vasospasm to cause further damage. Thus, early surgery is often chosen despite the overall risk.

Aneurysms that have been found by diagnostic testing and have not bled, do not necessarily require surgery. If the aneurysm is less than 10 mm in diameter, the patient usually will be monitored. If the aneurysm measures greater than 10 mm in diameter, surgery or treatment with balloons or coils delivered through a tube (catheter) in the blood vessel may be considered.

Preventing complications is a main concern of the stroke team. When a patient is bedridden for a long period of time, blood becomes stagnant and tends to pool, which may make the patient more prone to developing blood clots, resulting in further damage and even death. Lying in the same position for a long time can also cause painful bedsores and the shortening of muscles (contractures). Initially, the stroke team will move an immobilized patient and perform range of motion exercises to keep muscles limber. As the patient gains ability, he or she can take over some of these exercises to help prevent complications. Stroke patients are also at higher risk for infection, and are carefully monitored by the doctor and nurses to ensure that they remain as healthy as possible.

In the first few hours after a stroke, it can become fairly clear what the prognosis for the patient will be. In some cases the result of stroke can be more grievous than death, and the family will be told what they can expect. At a time when emotions are so highly charged, it may be difficult to make a decision that is best for the patient, especially if the patient is unable to communicate his or wishes. Situations like this can be avoided by having a living will or an advance health care directive in place. This document is prepared beforehand for emergency situations and lets the doctors and family know what the patient would like done in certain situations if he or she is unable to communicate. For example, an incapacitated patient who goes into cardiac arrest may not wish to be revived. This is something that can be established legally before a catastrophic event. Advance health care directives may have different names and different regulations governing them in the states and provinces. Having an advance health care directive in place makes the persons wishes clear and removes the burden of not knowing what to do from the family.

Rehabilitation

Rehabilitation begins as soon as possible after stroke, and recovery involves several different health disciplines. Along with the stroke survivor and his or her family and friends, the recovery team can include the physician, nurses, physiotherapist, occupational therapist, speech therapist, dietitian, social worker, and psychologist.

Not knowing the effects of a stroke is one of the most frightening aspects when beginning rehabilitation. The stroke survivor is faced with the prospect of not only lasting physical disability, but also lasting mental disability. The extent of damage that the stroke survivor must overcome depends largely on the type of stroke experienced and where the stroke damaged the brain. The rehabilitation team is there to support the patient and the family in recovering lost ability and learning to accept what cannot be changed.

The rehabilitation teams first task begins as soon as the patients health has stabilized. The main goals are to prevent a second stroke and avoid any complications that may delay recovery. Keeping the patient as mobile as possible helps to prevent blood clots from forming and any stiffening of the joints.

Common effects on muscles and movement of the patient include weakness, paralysis, spasticity, loss of sensation, and loss of bladder and bowel control. Most patients suffer from some sort of muscle weakness after stroke, either because the muscle has been directly affected or because the muscle is atrophying from lack of use. Paralysis is another common effect and tends to involve one side of the body. If the arm and the leg on the same side of the body are affected, it is referred to as hemiplegia. Rehabilitation concentrates on maximum recovery of use of the paralyzed limbs, but if recovery is limited or not possible, the rehabilitation team teaches the patient techniques to compensate.

Spasticity occurs when the brain loses control over the contraction of a muscle and the muscle contracts involuntarily. It is a common physical response to any injury to the brain. The muscle does not, and cannot, obey the brains signals to relax, and remains stiff, taut, and painful. Spasticity sometimes is reduced but more often than not it remains. Physiotherapists help move the affected limbs through range of motion exercises to stretch the muscle, and casts, splints, or local anesthesia may be used as temporary measures. Any medication to treat spasticity must be used with caution, so as not to interfere with any medication being taken to control the stroke. Only in rare, severe cases is surgery performed.

Damage to one side of the brain can cause the patient to lose sensation in the opposite side of the body. For instance, some patients scalded themselves with water because they could not feel its temperature. The rehabilitation team can help set up the stroke survivors home with basic safety features to avoid such mishaps.

Difficulty with bladder and bowel control happens to some stroke patients. The most common problem is frequency. The patients must empty their bladder more often and cannot avoid wetting accidents if a toilet cannot be found quickly. Bowel incontinence is not as common and both conditions can be helped by the use of medication and adult diapers.

Speech problems are common in stroke survivors. This can be one of the hardest aspects of stroke recovery because many people associate mental incompetence with speech disorders. Speech disorders are a result of the brain being unable to function properly rather than a reflection of mental competence.

There are two basic categories of speech disability: aphasia and dysarthria. Aphasia, a disorder of language, can be divided into two main categories: expressive, or Braces aphasia (the most common form of aphasia) is the term used when a patient cannot express thoughts verbally or in writing. Frustration is common in patients with aphasia because they understand what people say to them and they know how they want to respond but are unable to find and say the proper words. Receptive, or Wernickes aphasia, occurs when the patient cannot understand spoken or written language.

Dysarthria is a speech disorder that causes the patient to slur words or make the pronunciation hard to understand. Pitch of the voice and ability to control the volume of voice may also be affected. As soon as possible, a speech therapist will involve the patient in a series of exercises to try to recover any lost function of the brain. Over time, aphasia and dysarthria can sometimes be partially reversed.

Helping the patient to adapt is a key function of the rehabilitation team. They can teach the patient and the family new methods for coping and techniques that will make routine tasks easier. Practicing routines with the patient also plays a part, particularly when the patient is having difficulty thinking. It is common for the stroke survivor to suffer from a decreased attention span, lack of concentration, limited memory, or decreased ability to make a decision or solve a problem. The rehabilitation team can provide simple, step-by-step instructions and practice a routine with a patient who is having difficulty remembering how to start a task or difficulty processing the steps required to finish it. Accepting that it may take longer to think, make decisions, or complete tasks can help reduce the frustration that the patient feels.

Stroke often makes a formerly independent individual dependent on others for even the most basic tasks. This can leave the individual with feelings of anger, inadequacy, unworthiness, and discouragement. As a result, clinical depression is a very common aftereffect of stroke, not only for the stroke survivor but for the care-giver as well. Depression is a natural reaction to any loss, and the rehabilitation team can help the stroke survivor and the family come to terms with the loss by offering methods for coping, contact with support groups, and, in some cases, medication.

A patient who is depressed after a stroke also commonly suffers from emotional lability, the dramatic swing of emotions from tears to laughter and back. This swing is uncontrollable and may appear to happen for no reason at all. Fortunately these responses tend to occur less often over time.

When the brain is injured as a result of stroke, personality and behavior may change. A stroke survivor who previously was always cheerful and helpful, may now be surly and despondent. Emotional and behavioral responses to stroke are often interlinked. The stroke survivor may have damage in a part of the frontal lobe that is causing him or her to act in such a manner, and may also be reacting emotionally to a sudden and devastating situation. A physicians diagnosis and the rehabilitation teams support will help the patient and their family find ways to cope with all of the changes.

There is no set timeline for the recovery of stroke survivors; however, neurological recovery tends to peak within the first few months after a stroke and then lessen. The physical recovery tends to be slower than the neurological recovery but usually continues for a longer period of time. Ultimately, the earlier recovery begins the better the prognosis, though individual determination and a strong support system have proven to be big factors in the recovery of stroke survivors.

Risk factors

There are many factors to consider when assessing risk for stroke. Some risk factors are nontreatable and some are treatable, and there are other factors that protect against stroke. The first step is to have a medical assessment of risk. If risk factors are managed and protective, and factors are enhanced in accordance with medical advice, then chances of having a stroke will decrease.

Nontreatable risk factors include age, gender, family history, and ethnicity. In general, the greater the age the greater the risk for stroke; however, it is important to note that someone young or seemingly healthy may still be at risk for stroke. Stroke has been documented as early as when a child is still in the womb. Such cases are less common, but the important point is that it is never too soon to be aware of risk factors for stroke.

Traditionally stroke has been associated with men. This is not the case at all. From the ages forty-five to seventy-five, men tend to have more strokes than women, but from ages fifty-five to eighty-five, women assume similar risks to men. While initially the number of strokes for men may be slightly higher than for women, the effects on women tend to be more devastating. Many more men recover from stroke than do women. Heart attack and stroke account for more deaths in women than any other disease. The notion that stroke is gender-specific is a dangerous one. Both sexes need to be aware of risk factors for stroke.

Hypertension, diabetes, and a history of heart disease are three main factors considered when taking a family medical history. Hypertension and diabetes are often inherited, and are both risk factors; heart disease may suggest a tendency to have hardening of the arteries (atherosclerosis). While individuals cannot escape their family history, they can use it to their advantage by making their doctor aware of conditions in their family that put them at risk for stroke.

Similarly, ethnicity cannot be controlled. Studies have shown stroke to be an important concern for Asian and African-American populations, whose risk for stroke is slightly higher than for Caucasians.

With medical advice, the following treatable risk factors can be managed and the chance for stroke reduced.

High blood pressure makes the muscular wall of blood vessels thicker. When the walls cannot thicken any more to accommodate the increasing blood pressure, they become brittle. This can result in the blood vessel closing off or rupturing, thus causing bleeding in the brain.

Smoking is a risk factor for all types of stroke as well as for heart disease. It directly damages the lining of the arteries. Smoking breaks down the elastin that gives the blood vessels flexibility. For a person who smokes, the risk of sudden death from heart attack doubles.

Homocystenemia leads to hardening of the arteries and increased clotting of the blood. High levels of the natural chemical homocysteine in the blood can be treated with vitamin B-6, vitamin B-12, and folate.

High cholesterol builds up deposits in the lining of the blood vessels, making it more difficult for blood to flow through and increasing the chances of a blockage resulting in stroke.

Diabetes damages the lining of blood vessels, which can lead to stroke.

Weight is an indirect risk factor for stroke. In general, a healthy body weight improves overall health and reduces the potential risk for disorders, such as high blood pressure, high cholesterol, and diabetes that may lead to stroke.

Heart disease can lead to clots forming on damaged areas of the heart and then finding their way to the brain, resulting in stroke.

Prior strokes increase the risk for later strokes. The medical history may indicate that a continued risk for stroke, but with medical attention the risk may be reduced.

TIAs are the bodys way of warning that a person is at risk for stroke. Those affected should seek medical attention immediately.

Chiropractic treatment involving vigorous twisting of the neck can shear the lining of the arteries in the brain, potentially leading to stroke. Individuals who are at risk for stroke may want to consider the type of treatment they receive.

Oral contraceptives used to contain a higher dose of estrogen, which could increase the chance of stroke. Low-estrogen contraceptives do not put women at risk for stroke unless they also smoke; in that case, the combination increases the chances for stroke.

Medications in rare cases, have been linked to heart valve damage, high blood pressure, seizures, heart attack, stroke, and death. Using medication only when necessary and following instructions, are important because misuse of a safe medication can increase the risk of stroke.

Substance abuse can cause stroke. Cocaine increases blood pressure dramatically and if the individual has weakened blood vessels, a major stroke will follow. Heroin inflames the blood vessels, thus increasing the risk for stroke. Contaminated needles are also a concern because they can cause an infection in the heart valves that will produce clots that go to the brain.

Migraine headaches do not necessarily warn of a stroke, but it has been documented that people who suffer from migraine with visual symptoms (classical migraine) are at a slightly higher risk for stroke. The combination of migraine headaches and either smoking or taking birth control pills can also increase the risk for stroke.

Stress is unavoidable for most people, but the degree of stress and how an individual handles stress are important factors in controlling the risk for stroke. Studies have indicated that stress and the way it is handled is an indirect factor for stroke based on elevated blood pressure and progression of atherosclerosis.

Enhancing protective factors can also reduce the risk for stroke. These factors include diet, exercise, estrogen, and aspirin. A doctor will be able to give more individualized information. Not every patient will benefit by taking aspirin as a preventive measure, nor will all women require estrogen replacement therapy.

A healthy diet, reducing alcohol consumption, and a moderate exercise plan are good ideas for prevention of many medical diseases, including stroke and heart disease. Again, it is a good idea to meet with a medical professional before making major changes so that the patient can be advised how to proceed and what to be aware of.

Prevention

The best way to prevent stroke or reduce the chances for stroke is to manage the risk factors listed above. In more serious cases, a physician may prescribe medication or recommend surgery.

The two main factors that lead to stroke are disease in the large and small arteries (atherosclerosis) and heart disease. In these conditions, clots can form and travel to the brain. Two main types of medication are prescribed for treatment: antiplatelet drugs and anticoagulant drugs. Antiplatelet drugs prevent clots by preventing the clumping of blood cells. These drugs include aspirin, ticlopidine, Clopidogrel, and dipyridamole. They prevent clots by thinning the blood, and include warfarin and coumadin.

Under the right circumstances, surgery can be used to considerably reduce the chance of stroke in an individual. The most common and most successful procedure is a carotid endarterectomy, first performed in the 1950s. If a patient has been found to have a narrowing in the carotid artery (the artery that takes blood to the brain), then surgery may be required to remove the narrowing. Surgery is not beneficial or even necessary in every case, so it is best to consult a specialist.

Perhaps the biggest part of prevention is knowledge, including learning the warning signs for stroke, having an annual check-up, and being aware of risk factors that can be controlled; educating oneself but not diagnosing oneself (instead consulting a professional) if unsure; and, making sure that information comes from a reliable source. It is best to rely on stroke information from national organizations because the main purpose of television is to entertain (e.g., certain information may be sensationalized), and information on the Internet can come from anyone.

Vladimir Hachinski Larissa Hachinski

See also Cholesterol; Diabetes Mellitus; Epilepsy; Heart Disease; High Blood Pressure; Language Disorders; Pressure Ulcers; Rehabilitation; Vascular Dementia.

BIBLIOGRAPHY

Adair E. S., and Pfalzgraf, B. Pathways: Moving beyond Stroke and Aphasia. Detroit, Mich: Wayne State University Press, 1990.

Ahn, J., and Ferguson, G. Recovering from Stroke. York: HarperCollins, 1992.

American Heart Association. The American Heart Association Family Guide to Stroke Treatment, Recovery and Prevention. New York: Times Books, 1994.

Ancowitz, A. The Stroke Book. New York: William Morrow & Company, 1993.

Bergquist, W. H.; McClean, R.; and Kobylinski, B. A. Stroke Survivors. San Francisco: Jossey-Bass, 1994.

Donahue, P. J. How to Prevent a Stroke: A Complete Risk-Reduction Program. Emmaus, Penn: Rodale Press, 1989.

Foley, C., and Pizer, H. F. The Stroke Fact Book. New York: Bantam Books, 1985.

Gordon, N. F. Stroke: Your Complete Exercise Guide. Champaign, Ill: Human Kinetics Publishers, 1993.

Heart and Stroke Foundation of Canada. The Canadian Family Guide to Stroke Prevention, Treatment and Recovery. Toronto, Ontario: Random House of Canada, 1996.

Josephs, A. The Invaluable Guide to Life After Stroke: An Owners Manual. Long Beach, Calif.: Amadeus Press, 1992.

Klein, B. S. Slow Dance, A Story of Stroke, Love and Disability. Toronto, Ontario: Knopf Canada, 1997.

Larkin, M. When Someone You Love Has a Stroke. A National Stroke Association Book. New York: Dell Publishing, 1995.

McCrum, R. My Year Off. Toronto, Ontario: Knopf Canada, 1998. National Stroke Association. Living at Home after Your Stroke. Englewood, Col.: National Stroke Association, 1994.

Newborn, B. Return to Ithaca. Rockport, Mass.: Element Books Limited, 1997.

Senelick, R. C.; Rossi, P. W.; and Dougherty, K. Living with Stroke: A Guide for Families. Chicago, Ill: Contemporary Books, 1999.

Shinberg, E. F. Strokes: What Families Should Know. Westminister, Mary.: Random House, 1990.

Weiner, F.; Lee, M.; and Bell, H. Recovering at Home after a Stroke: A Practical Guide for You and Your Family. New York: The Body Press/Perigee Books, 1994.

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Hachinski, Vladimir; Hachinski, Larissa. "Stroke." Encyclopedia of Aging. 2002. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

Hachinski, Vladimir; Hachinski, Larissa. "Stroke." Encyclopedia of Aging. 2002. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1G2-3402200392.html

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Stroke

Stroke

Definition

A stroke is the sudden death of brain cells in a localized area due to inadequate blood flow.

Description

A stroke occurs when blood flow is interrupted to part of the brain. Without blood to supply oxygen and nutrients and to remove waste products, brain cells quickly begin to die. Depending on the region of the brain affected, a stroke may cause paralysis, speech impairment, loss of memory and reasoning ability, coma, or death. A stroke also is sometimes called a brain attack or a cerebrovascular accident (CVA).

Some important stroke statistics include:

  • more than one-half million people in the United States experience a new or recurrent stroke each year
  • stroke is the third leading cause of death in the United States and the leading cause of disability
  • stroke kills about 160,000 Americans each year, or almost one out of three stroke victims
  • three million Americans are currently permanently disabled from stroke
  • in the United States, stroke costs about $30 billion per year in direct costs and loss of productivity
  • two-thirds of strokes occur in people over age 65 but they can occur at any age
  • strokes affect men more often than women, although women are more likely to die from a stroke
  • strokes affect blacks more often than whites, and are more likely to be fatal among blacks

Stroke is a medical emergency requiring immediate treatment. Prompt treatment improves the chances of survival and increases the degree of recovery that may be expected. A person who may have suffered a stroke should be seen in a hospital emergency room without delay. Treatment to break up a blood clot, the major cause of stroke, must begin within three hours of the stroke to be effective. Improved medical treatment of all types of stroke has resulted in a dramatic decline in death rates in recent decades. In 1950, nine in ten died from stroke, compared to slightly less than one in three in the twenty-first century. However, about two-thirds of stroke survivors will have disabilities ranging from moderate to severe.

Causes and symptoms

Causes

There are four main types of stroke. Cerebral thrombosis and cerebral embolism are caused by blood clots that block an artery supplying the brain, either in the brain itself or in the neck. These account for 70-80% of all strokes. Subarachnoid hemorrhage and intracerebral hemorrhage occur when a blood vessel bursts around or in the brain.

Cerebral thrombosis occurs when a blood clot, or thrombus, forms within the brain itself, blocking the flow of blood through the affected vessel. Clots most often form due to "hardening" (atherosclerosis ) of brain arteries. Cerebral thrombosis occurs most often at night or early in the morning. Cerebral thrombosis is often preceded by a transient ischemic attack, or TIA, sometimes called a "mini-stroke." In a TIA, blood flow is temporarily interrupted, causing short-lived stroke-like symptoms. Recognizing the occurrence of a TIA, and seeking immediate treatment, is an important step in stroke prevention.

Cerebral embolism occurs when a blood clot from elsewhere in the circulatory system breaks free. If it becomes lodged in an artery supplying the brain, either in the brain or in the neck, it can cause a stroke. The most common cause of cerebral embolism is atrial fibrillation, a disorder of the heart beat. In atrial fibrillation, the upper chambers (atria) of the heart beat weakly and rapidly, instead of slowly and steadily. Blood within the atria is not completely emptied. This stagnant blood may form clots within the atria, which can then break off and enter the circulation. Atrial fibrillation is a factor in about 15% of all strokes. The risk of a stroke from atrial fibrillation can be dramatically reduced with daily use of anticoagulant medication.

Hemorrhage, or bleeding, occurs when a blood vessel breaks, either from trauma or excess internal pressure. The vessels most likely to break are those with preexisting defects such as an aneurysm. An aneurysm is a "pouching out" of a blood vessel caused by a weak arterial wall. Brain aneurysms are surprisingly common. According to autopsy studies, about 6% of all Americans have them. Aneurysms rarely cause symptoms until they burst. Aneurysms are most likely to burst when blood pressure is highest, and controlling blood pressure is an important preventive strategy.

Intracerebral hemorrhage affects vessels within the brain itself, while subarachnoid hemorrhage affects arteries at the brain's surface, just below the protective arachnoid membrane. Intracerebral hemorrhages represent about 10% of all strokes, while subarachnoid hemorrhages account for about 7%.

In addition to depriving affected tissues of blood supply, the accumulation of fluid within the inflexible skull creates excess pressure on brain tissue, which can quickly become fatal. Nonetheless, recovery may be more complete for a person who survives hemorrhage than for one who survives a clot, because the blood deprivation effects usually are not as severe.

Death of brain cells triggers a chain reaction in which toxic chemicals created by cell death affect other nearby cells. This is one reason why prompt treatment can have such a dramatic effect on final recovery.

Risk factors

Risk factors for stroke involve age, sex, heredity, predisposing diseases or other medical conditions, use of certain medications, and lifestyle choices:

  • Age and sex. The risk of stroke increases with age, doubling for each decade after age 55. Men are more likely to have a stroke than women.
  • Heredity. Blacks, Asians, and Hispanics have higher rates of stroke than do whites, related partly to higher blood pressure. People with a family history of stroke are at greater risk.
  • Diseases. Stroke risk is increased for people with diabetes, heart disease (especially atrial fibrillation), high blood pressure, prior stroke, or TIA. Risk of stroke increases tenfold for someone with one or more TIAs.
  • Other medical conditions. Stroke risk increases with obesity, high blood cholesterol level, or high red blood cell count.
  • Hormone replacement therapy. In mid-2003, a large clinical trial called the Women's Health Initiative was halted when researchers discovered several potentially dangerous effects of combined hormone replacement therapy on postmenopausal women. In addition to increasing the risk of some cancers and dementia, combined estrogen and progesterone therapy increased risk of ischemic stroke by 31% among study participants.
  • Lifestyle choices. Stroke risk increases with cigarette smoking (especially if combined with the use of oral contraceptives ), low level of physical activity, alcohol consumption above two drinks per day, or use of cocaine or intravenous drugs.

Symptoms

Symptoms of an embolic stroke usually come on quite suddenly and are at their most intense right from the start, while symptoms of a thrombotic stroke come on more gradually. Symptoms may include:

  • blurring or decreased vision in one or both eyes
  • severe headache, often described as "the worst headache of my life"
  • weakness, numbness, or paralysis of the face, arm, or leg, usually confined to one side of the body
  • dizziness, loss of balance or coordination, especially when combined with other symptoms

Diagnosis

The diagnosis of stroke is begun with a careful medical history, especially concerning the onset and distribution of symptoms, presence of risk factors, and the exclusion of other possible causes. A brief neurological exam is performed to identify the degree and location of any deficits, such as weakness, incoordination, or visual losses.

Once stroke is suspected, a computed tomography scan (CT scan) or magnetic resonance imaging (MRI) scan is performed to distinguish a stroke caused by blood clot from one caused by hemorrhage, a critical distinction that guides therapy. Blood and urine tests are done routinely to look for possible abnormalities.

Other investigations that may be performed to guide treatment include an electrocardiogram, angiography, ultrasound, and electroencephalogram.

Treatment

Emergency treatment

Emergency treatment of stroke from a blood clot is aimed at dissolving the clot. This "thrombolytic therapy" currently is performed most often with tissue plasminogen activator, or t-PA. t-PA must be administered within three hours of the stroke event. Therefore, patients who awaken with stroke symptoms are ineligible for t-PA therapy, as the time of onset cannot be accurately determined. t-PA therapy has been shown to improve recovery and decrease long-term disability in selected patients. t-PA therapy carries a 6.4% risk of inducing a cerebral hemorrhage, and is not appropriate for patients with bleeding disorders, very high blood pressure, known aneurysms, any evidence of intracranial hemorrhage, or incidence of stroke, head trauma, or intracranial surgery within the past three months. Patients with clot-related (thrombotic or embolic) stroke who are ineligible for t-PA treatment may be treated with heparin or other blood thinners, or with aspirin or other anti-clotting agents in some cases.

Emergency treatment of hemorrhagic stroke is aimed at controlling intracranial pressure. Intravenous urea or mannitol plus hyperventilation is the most common treatment. Corticosteroids also may be used. Patients with reversible bleeding disorders, such as those due to anticoagulant treatment, should have these bleeding disorders reversed, if possible.

Surgery for hemorrhage due to aneurysm may be performed if the aneurysm is close enough to the cranial surface to allow access. Ruptured vessels are closed off to prevent rebleeding. For aneurysms that are difficult to reach surgically, endovascular treatment may be used. In this procedure, a catheter is guided from a larger artery up into the brain to reach the aneurysm. Small coils of wire are discharged into the aneurysm, which plug it up and block off blood flow from the main artery.

Rehabilitation

Rehabilitation refers to a comprehensive program designed to regain function as much as possible and compensate for permanent losses. Approximately 10% of stroke survivors are without any significant disability and able to function independently. Another 10% are so severely affected that they must remain institutionalized for severe disability. The remaining 80% can return home with appropriate therapy, training, support, and care services.

Rehabilitation is coordinated by a team of medical professionals and may include the services of a neurologist, a physician who specializes in rehabilitation medicine (physiatrist), a physical therapist, an occupational therapist, a speech-language pathologist, a nutritionist, a mental health professional, and a social worker. Rehabilitation services may be provided in an acute care hospital, rehabilitation hospital, long-term care facility, outpatient clinic, or at home.

The rehabilitation program is based on the patient's individual deficits and strengths. Strokes on the left side of the brain primarily affect the right half of the body, and vice versa. In addition, in left brain dominant people, who constitute a significant majority of the population, left brain strokes usually lead to speech and language deficits, while right brain strokes may affect spatial perception. Patients with right brain strokes also may deny their illness, neglect the affected side of their body, and behave impulsively.

Rehabilitation may be complicated by cognitive losses, including diminished ability to understand and follow directions. Poor results are more likely in patients with significant or prolonged cognitive changes, sensory losses, language deficits, or incontinence.

PREVENTING COMPLICATIONS. Rehabilitation begins with prevention of stroke recurrence and other medical complications. The risk of stroke recurrence may be reduced with many of the same measures used to prevent stroke, including quitting smoking and controlling blood pressure.

One of the most common medical complications following stroke is deep venous thrombosis, in which a clot forms within a limb immobilized by paralysis. Clots that break free often become lodged in an artery feeding the lungs. This type of pulmonary embolism is a common cause of death in the weeks following a stroke. Resuming activity within a day or two after the stroke is an important preventive measure, along with use of elastic stockings on the lower limbs. Drugs that prevent clotting may be given, including intravenous heparin and oral warfarin.

Weakness and loss of coordination of the swallowing muscles may impair swallowing (dysphagia), and allow food to enter the lower airway. This may lead to aspiration pneumonia, another common cause of death shortly after a stroke. Dysphagia may be treated with retraining exercises and temporary use of pureed foods.

Depression occurs in 30-60% of stroke patients. Antidepressants and psychotherapy may be used in combination.

Other medical complications include urinary tract infections, pressure ulcers, falls, and seizures.

TYPES OF REHABILITATIVE THERAPY. Brain tissue that dies in a stroke cannot regenerate. In some cases, the functions of that tissue may be performed by other brain regions after a training period. In other cases, compensatory actions may be developed to replace lost abilities.

Physical therapy is used to maintain and restore range of motion and strength in affected limbs, and to maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for instance). The physical therapist advises on mobility aids such as wheelchairs, braces, and canes. In the recovery period, a stroke patient may develop muscle spasticity and contractures, or abnormal contractions. Contractures may be treated with a combination of stretching and splinting.

Occupational therapy improves self-care skills such as feeding, bathing, and dressing, and helps develop effective compensatory strategies and devices for activities of daily living. A speech-language pathologist focuses on communication and swallowing skills. When dysphagia is a problem, a nutritionist can advise alternative meals that provide adequate nutrition.

Mental health professionals may be involved in the treatment of depression or loss of thinking (cognitive) skills. A social worker may help coordinate services and ease the transition out of the hospital back into the home. Both social workers and mental health professionals may help counsel the patient and family during the difficult rehabilitation period. Caring for a person affected with stroke requires learning a new set of skills and adapting to new demands and limitations. Home caregivers may develop stress, anxiety, and depression. Caring for the caregiver is an important part of the overall stroke treatment program.

Support groups can provide an important source of information, advice, and comfort for stroke patients and for caregivers. Joining a support group can be one of the most important steps in the rehabilitation process.

Prognosis

Stroke is fatal for about 27% of white males, 52% of black males, 23% of white females, and 40% of black females. Stroke survivors may be left with significant deficits. Emergency treatment and comprehensive rehabilitation can significantly improve both survival and recovery. A 2003 study found that treating people who have had a stroke with certain antidepressant medications, even if they were not depressed, could increase their chances of living longer. People who received the treatment were less likely to die from cardiovascular events than those who did not receive antidepressant drugs.

Prevention

Damage from stroke may be significantly reduced through emergency treatment. Knowing the symptoms of stroke is as important as knowing those of a heart attack. Patients with stroke symptoms should seek emergency treatment without delay, which may mean dialing 911 rather than their family physician.

The risk of stroke can be reduced through lifestyle changes:

  • quitting smoking
  • controlling blood pressure
  • getting regular exercise
  • keeping body weight down
  • avoiding excessive alcohol consumption
  • getting regular checkups and following the doctor's advice regarding diet and medicines, particularly hormone replacement therapy.

Treatment of atrial fibrillation may significantly reduce the risk of stroke. Preventive anticoagulant therapy may benefit those with untreated atrial fibrillation. Warfarin (Coumadin) has proven to be more effective than aspirin for those with higher risk. A new drug called ximelagatran (Exanta) with fewer side effects has been introduced in Europe. The drug's manufacturer was applying for FDA approval to market the drug for use in preventing stroke and other thromboembolic complications in early 2004.

In 2003, physicians at the Framingham Heart Study derived new risk scores to help physicians determine which patients with new onset of atrial fibrillation are at higher risk for stroke alone or for stroke or death. Screening for aneurysms may be an effective preventive measure in those with a family history of aneurysms or autosomal polycystic kidney disease, which tends to be associated with aneurysms.

Resources

PERIODICALS

"HRT Increases Risk of Dementia and Stroke." Contemporary OB/GYN July 2003: 16-21.

"New Classification Scheme Helpful to Predict Risk of Stroke or Death." Heart Disease Weekly September 14, 2003: 3.

"New Drug Application Submitted to FDA for Exanta." Heart Disease Weekly January 25, 2004: 79.

"New Stroke Prevention Drug." Chemist & Druggist September 13, 2003: 24.

"Post-stroke Antidepressant Treatment Appears to Reduce Death Rate." Heart Disease Weekly October 26, 2003: 56.

ORGANIZATIONS

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.

National Stroke Association. 9707 E. Easter Lane, Englewood, Co. 80112. (800) 787-6537. http://www.stroke.org.

KEY TERMS

Aneurysm A pouchlike bulging of a blood vessel. Aneurysms can rupture, leading to stroke.

Atrial fibrillation A disorder of the heart beat associated with a higher risk of stroke. In this disorder, the upper chambers (atria) of the heart do not completely empty when the heart beats, which can allow blood clots to form.

Cerebral embolism A blockage of blood flow through a vessel in the brain by a blood clot that formed elsewhere in the body and traveled to the brain.

Cerebral thrombosis A blockage of blood flow through a vessel in the brain by a blood clot that formed in the brain itself.

Intracerebral hemorrhage A cause of some strokes in which vessels within the brain begin bleeding.

Subarachnoid hemorrhage A cause of some strokes in which arteries on the surface of the brain begin bleeding.

Tissue plasminogen activator (tPA) A substance that is sometimes given to patients within three hours of a stroke to dissolve blood clots within the brain.

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Robinson, Richard; Odle, Teresa. "Stroke." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

Robinson, Richard; Odle, Teresa. "Stroke." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1G2-3451601555.html

Robinson, Richard; Odle, Teresa. "Stroke." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3451601555.html

Stroke

Stroke

Definition

A stroke is the sudden death of brain cells in a localized area due to inadequate blood flow.

Description

A stroke occurs when blood flow is interrupted to part of the brain. Without blood to supply oxygen and nutrients and to remove waste products, brain cells quickly begin to die. Depending on the region of the brain affected, a stroke may cause paralysis, speech impairment, a loss of memory and reasoning ability, coma, or death. A stroke is also sometimes called a brain attack or a cerebrovascular accident (CVA).

Some important stroke statistics include:

  • More than half a million people in the United States experience a new or recurrent stroke each year.
  • Stroke is the third leading cause of death in the United States and the leading cause of disability.
  • Stroke kills about 150,000 Americans each year, or almost one out of three stroke victims.
  • Three million Americans are currently permanently disabled from stroke.
  • In the United States, stroke costs about $30 billion per year in direct costs and loss of productivity.
  • Two-thirds of strokes occur in people over age 65.
  • Strokes affect men more often than women, although women are more likely to die from a stroke.
  • Strokes affect blacks more often than whites, and are more likely to be fatal among blacks.

Stroke is a medical emergency requiring immediate treatment. Prompt treatment improves the chances of survival and increases the degree of recovery that may be expected. A person who may have suffered a stroke should be seen in a hospital emergency room without delay. Treatment to break up a blood clot, the major cause of stroke, must begin within three hours of the stroke to be effective. Improved medical treatment of all types of stroke has resulted in a dramatic decline in death rates in recent decades. In 1950, nine in 10 people died from stroke, compared to slightly less than one in three today.

Causes and symptoms

Causes

There are four main types of stroke. Cerebral thrombosis and cerebral embolism are caused by blood clots that block an artery supplying the brain, either in the brain itself or in the neck. These account for 7080% of all strokes. Subarachnoid hemorrhage and intracerebral hemorrhage occur when a blood vessel bursts around or in the brain.

Cerebral thrombosis occurs when a blood clot, or thrombus, forms within the brain itself, blocking the flow of blood through the affected vessel. Clots most often form due to "hardening" (atherosclerosis) of brain arteries. Cerebral thrombosis occurs most often at night or early in the morning. Cerebral thrombosis is often preceded by a transient ischemic attack (TIA), sometimes called a "mini-stroke." In a TIA, blood flow is temporarily interrupted, causing short-lived stroke-like symptoms. Recognizing the occurrence of a TIA and seeking immediate treatment are important steps in stroke prevention.

Cerebral embolism occurs when a blood clot from elsewhere in the circulatory system breaks free. If it becomes lodged in an artery supplying the brain, either in the brain or in the neck, it can cause a stroke. The most common cause of cerebral embolism is atrial fibrillation, a disorder of the heartbeat. In atrial fibrillation, the upper chambers (atria) of the heart beat weakly and rapidly, instead of slowly and steadily. Blood within the atria is not completely emptied. This stagnant blood may form clots within the atria, which can then break off and enter the circulation. Atrial fibrillation is a factor in about 15% of all strokes. The risk of a stroke from atrial fibrillation can be dramatically reduced with daily use of anticoagulant medication.

Hemorrhage, or bleeding, occurs when a blood vessel breaks, either from trauma or excess internal pressure. The vessels most likely to break are those with preexisting defects such as an aneurysm. An aneurysm is a "pouching out" of a blood vessel caused by a weak arterial wall. Brain aneurysms are surprisingly common. According to autopsy studies, about 6% of all Americans have them. Aneurysms rarely cause symptoms until they burst. Aneurysms are most likely to burst when blood pressure is highest, and controlling blood pressure is an important preventive strategy.

Intracerebral hemorrhage affects vessels within the brain itself, while subarachnoid hemorrhage affects arteries at the brain's surface, just below the protective arachnoid membrane. Intracerebral hemorrhages represent about 10% of all strokes, while subarachnoid hemorrhages account for about 7%.

In addition to depriving affected tissues of blood supply, the accumulation of fluid within the inflexible skull creates excess pressure on brain tissue, which can quickly lead to death. Nonetheless, recovery may be more complete for a person who survives hemorrhage than for one who survives a clot, because the blood deprivation effects are usually not as severe.

Death of brain cells triggers a chain reaction in which toxic chemicals created by cell death affect other nearby cells. This is one reason why prompt treatment can have such a dramatic effect on final recovery.

Risk factors

Risk factors for stroke involve age, sex, heredity, predisposing diseases or other medical conditions, and lifestyle choices, including:

  • Age and sex. The risk of stroke increases with increasing age, doubling for each decade after age 55. Men are more likely to have a stroke than women.
  • Heredity. Blacks, Asians, and Hispanics all have higher rates of stroke than do whites, related partly to higher blood pressure. People with a family history of stroke are at greater risk.
  • Diseases. Stroke risk is increased for people with diabetes, heart disease (especially atrial fibrillation), high blood pressure, prior stroke, or TIA. Risk of stroke increases tenfold for someone with one or more TIAs.
  • Other medical conditions. Stroke risk increases with obesity, high blood cholesterol level, or high red blood cell count.
  • Lifestyle choices. Stroke risk increases with cigarette smoking (especially if combined with the use of oral contraceptives), low level of physical activity, alcohol consumption above two drinks per day, or use of cocaine or intravenous drugs.

Symptoms

Symptoms of an embolic stroke usually come on quite suddenly and are at their most intense right from the start, while symptoms of a thrombotic stroke come on more gradually. Symptoms may include:

  • blurring or decreased vision in one or both eyes
  • severe headache
  • weakness, numbness, or paralysis of the face, arm, or leg, usually confined to one side of the body
  • dizziness, loss of balance or coordination, especially when combined with other symptoms

Diagnosis

The diagnosis of stroke is begun with a careful medical history, especially concerning the onset and distribution of symptoms, presence of risk factors, and the exclusion of other possible causes. A brief neurological exam is performed to identify the degree and location of any deficits such as weakness, incoordination, or visual losses.

Once stroke is suspected, a computed tomography (CT ) scan or magnetic resonance imaging (MRI) scan is performed to distinguish a stroke caused by blood clot from one caused by hemorrhage, a critical distinction that guides therapy. Blood and urine tests are done routinely to look for possible abnormalities.

Other investigations that may be performed to guide treatment include an electrocardiogram, angiography , ultrasound, and electroencephalogram.

Treatment team

Stroke treatment involves a multidisciplinary team. Physicians are responsible for caring for the stroke survivor's general health and providing guidance aimed at preventing a second stroke. Neurologists usually lead acute-care stroke teams and direct patient care during hospitalization. The team may include a physiatrist (a specialist in rehabilitation), a rehabilitation nurse, a physical therapist, an occupational therapist, a speech-language pathologist, a social worker, a psychologist, and a vocational counselor.

Treatment

Emergency treatment

Emergency treatment of stroke from a blood clot is aimed at dissolving the clot. This "thrombolytic therapy" is currently performed most often with tissue plasminogen activator, or t-PA. This t-PA must be administered within three hours of the stroke event. Therefore, patients who awaken with stroke symptoms are ineligible for t-PA therapy, as the time of onset cannot be accurately determined. The t-PA therapy has been shown to improve recovery and decrease long-term disability in selected patients. The t-PA therapy carries a 6.4% risk of inducing a cerebral hemorrhage, and is not appropriate for patients with bleeding disorders, very high blood pressure, known aneurysms, any evidence of intracranial hemorrhage, or incidence of stroke, head trauma, or intracranial surgery within the past three months. Patients with clot-related (thrombotic or embolic) stroke who are ineligible for t-PA treatment may be treated with heparin or other blood thinners, or with aspirin or other anti-clotting agents in some cases.

Emergency treatment of hemorrhagic stroke is aimed at controlling intracranial pressure. Intravenous urea or mannitol plus hyperventilation are the most common treatments. Corticosteroids may also be used. Patients with reversible bleeding disorders such as those due to anticoagulant treatment should have these bleeding disorders reversed, if possible.

Surgery for hemorrhage due to aneurysm may be performed if the aneurysm is close enough to the cranial surface to allow access. Ruptured vessels are closed off to prevent rebleeding. For aneurysms that are difficult to reach surgically, endovascular treatment may be used. In this procedure, a catheter is guided from a larger artery up into the brain to reach the aneurysm. Small coils of wire are discharged into the aneurysm, which plug it up and block off blood flow from the main artery.

Recovery and rehabilitation

Rehabilitation refers to a comprehensive program designed to help the patient regain function as much as possible and compensate for permanent losses. Approximately 10% of stroke survivors are without any significant disability and able to function independently. Another 10% are so severely affected that they must remain institutionalized for severe disability. The remaining 80% can return home with appropriate therapy, training, support, and care services.

Rehabilitation is coordinated by a team that may include the services of a neurologist , a physiatrist, a physical therapist, an occupational therapist, a speech-language pathologist, a nutritionist, a mental health professional, and a social worker. Rehabilitation services may be provided in an acute care hospital, rehabilitation hospital, long-term care facility, outpatient clinic, or at home.

The rehabilitation program is based on the patient's individual deficits and strengths. Strokes on the left side of the brain primarily affect the right half of the body, and vice versa. In addition, in left-brain-dominant people, who constitute a significant majority of the population, left-brain strokes usually lead to speech and language deficits, while right-brain strokes may affect spatial perception. Patients with right-brain strokes may also deny their illness, neglect the affected side of their body, and behave impulsively.

Rehabilitation may be complicated by cognitive losses, including diminished ability to understand and follow directions. Poor results are more likely in patients with significant or prolonged cognitive changes, sensory losses, language deficits, or incontinence.

Preventing complications

Rehabilitation begins with prevention of stroke recurrence and other medical complications. The risk of stroke recurrence may be reduced with many of the same measures used to prevent stroke, including quitting smoking and controlling blood pressure.

One of the most common medical complications following stroke is deep venous thrombosis, in which a clot forms within a limb immobilized by paralysis. Clots that break free can often become lodged in an artery feeding the lungs. This type of pulmonary embolism is a common cause of death in the weeks following a stroke. Resuming activity within a day or two after the stroke is an important preventive measure, along with use of elastic stockings on the lower limbs. Drugs that prevent clotting may be given, including intravenous heparin and oral warfarin.

Weakness and loss of coordination of the swallowing muscles may impair swallowing (dysphagia), and allow food to enter the lower airway. This may lead to aspiration pneumonia, another common cause of death shortly after a stroke. Dysphagia may be treated with retraining exercises and temporary use of pureed foods.

Depression occurs in 3060% of stroke patients. Antidepressants and psychotherapy may be used in combination.

Other medical complications include urinary tract infections, pressure ulcers, falls, and seizures .

Types of rehabilitative therapy

Brain tissue that dies in a stroke cannot regenerate. In some cases, other brain regions may perform the functions of that tissue after a training period. In other cases, compensatory actions may be developed to replace lost abilities.

Physical therapy is used to maintain and restore range of motion and strength in affected limbs, and to maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for instance). The physical therapist advises on mobility aids such as wheelchairs, braces, and canes. In the recovery period, a stroke patient may develop muscle spasticity and contractures, or abnormal contractions. Contractures may be treated with a combination of stretching and splinting.

Occupational therapy improves self-care skills such as feeding, bathing, and dressing, and helps develop effective compensatory strategies and devices for activities of daily living. A speech-language pathologist focuses on communication and swallowing skills. When dysphagia is a problem, a nutritionist can advise alternative meals that provide adequate nutrition.

Mental health professionals may be involved in the treatment of depression or loss of thinking (cognitive) skills. A social worker may help coordinate services and ease the transition out of the hospital back into the home. Both social workers and mental health professionals may help counsel the patient and family during the difficult rehabilitation period. Caring for a person affected with stroke requires learning a new set of skills and adapting to new demands and limitations. Home caregivers may develop stress, anxiety, and depression. Caring for the care-giver is an important part of the overall stroke treatment program.

Support groups can provide an important source of information, advice, and comfort for stroke patients and for caregivers. Joining a support group can be one of the most important steps in the rehabilitation process.

Clinical trials

As of mid-2004, there were numerous open clinical trials for stroke, including:

  • "Adjunctive Drug Treatment for Ischemic Stroke Patients," "E-Selectin Nasal Spray to Prevent Stroke Recurrence," "Improving Motor Learning in Stroke Patients," "Aspirin or Warfarin to Prevent Stroke," "Hand Exercise and Upper Arm Anesthesia to Improvements Hand Function in Chronic Stroke Patients," "Preliminary Study of Transcranial Magnetic Stimulation for Stroke Rehabilitation," and "Using fMRI to Understand the Roles of Brain Areas for Fine Hand Movements" are all sponsored by the National Institute of Neurological Disorders and Stroke.
  • "Preventing Post-Stroke Depression" is sponsored by the National Institute of Mental Health (NIMH).
  • "Walking Therapy in Hemiparetic Stroke Patients Using Robotic-Assisted Treadmill Training" is sponsored by the United States Department of Education.
  • "Brain Processing of Language Meanings" is sponsored by Warren G. Magnuson Clinical Center.

Updated information on these and other ongoing trials for the study and treatment of stroke can be found at the National Institutes of Health Web site for clinical trials at <http://www.clinicaltrials.org>.

Prognosis

Stroke is fatal for about 27% of white males, 52% of black males, 23% of white females, and 40% of black females. Stroke survivors may be left with significant deficits. Emergency treatment and comprehensive rehabilitation can significantly improve both survival and recovery.

Prevention

Damage from stroke may be significantly reduced through emergency treatment. Knowing the symptoms of stroke is as important as knowing those of a heart attack. Patients with stroke symptoms should seek emergency treatment without delay, which may mean dialing 911 rather than their family physician.

The risk of stroke can be reduced through lifestyle changes, including:

  • stopping smoking
  • controlling blood pressure
  • getting regular exercise
  • keeping weight down
  • avoiding excessive alcohol consumption
  • getting regular checkups and following the doctor's advice regarding diet and medicines

Treatment of atrial fibrillation may significantly reduce the risk of stroke. Preventive anticoagulant therapy may benefit those with untreated atrial fibrillation. Warfarin (Coumadin) has proven to be more effective than aspirin for those with higher risk.

Screening for aneurysms may be an effective preventive measure in those with a family history of aneurysms or autosomal polycystic kidney disease, which tends to be associated with aneurysms.

Resources

BOOKS

Caplan, L. R., M. L. Dyken, and J. D. Easton. American Heart Association Family Guide to Stroke Treatment, Recovery, and Prevention. New York: Times Books, 1996.

Warlow, C. P., et al. Stroke: A Practical Guide to Management. Boston: Blackwell Science, 1996.

Weiner F., M. H. M. Lee, and H. Bell. Recovering at Home After a Stroke: A Practical Guide for You and Your Family. Los Angeles: The Body Press/Perigee Books, 1994.

PERIODICALS

Selman, W. R., R. Tarr, and D. M. D. Landis. "Brain Attack: Emergency Treatment of Ischemic Stroke." American Family Physician 55 (June 1997): 26552662.

Wolf, P. A., and D. E. Singer. "Preventing Stroke in Atrial Fibrillation." American Family Physician (December 1997).

ORGANIZATIONS

National Stroke Association. 9707 E. Easter Lane, Englewood, Co. 80112. (800) 787-6537. (June 3, 2004). <http://www.stroke.org>.

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. (June 3, 2004). <http://www.americanheart.org>.

Richard Robinson

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Robinson, Richard. "Stroke." Gale Encyclopedia of Neurological Disorders. 2005. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3435200334.html

Stroke

Stroke

Definition

A stroke, also called a cerebral vascular accident (CVA), is the sudden death of cells in a specific area of the brain due to inadequate blood flow.

Description

A stroke occurs when blood flow is interrupted to a part of the brain, either when an artery bursts or becomes closed when a blood clot lodges in it. Blood circulation to the area of the brain served by that artery stops at the point of disturbance, and the brain tissue beyond that is damaged or dies. (Brain cells need blood to supply oxygen and nutrients and to remove waste products.) Depending on the region of the brain affected, a stroke can cause paralysis, loss of vision, speech impairment, memory loss and reasoning ability, coma, or death. The effects of a stroke are determined by how much damage occurs, and which portion of the brain is affected.

About a third of all strokes are preceded by transient ischemic attacks (TIAs), or mini-strokes, that temporarily interrupt blood flow to the brain. While TIAs cause similar symptoms (such as sudden vision loss or temporary weakness in a limb), they abate much more quickly than full-fledged strokes, usually within a few hours sometimes as quickly as a few minutes.

Stroke is a medical emergency requiring immediate treatment. Prompt treatment improves the chances of survival and increases the degree of recovery that may be expected. A person who may have suffered a stroke should be seen in a hospital emergency room without delay. Treatment to break up a blood clot, the major cause of stroke, must begin within three hours of the stroke to be most effective. Improved medical treatment of all types of stroke has resulted in a dramatic decline in death rates in recent decades. In 1950 nine in ten stroke victims died, compared to slightly less than one in three today.

Causes and symptoms

Causes

There are four main types of stroke: cerebral thrombosis, cerebral embolism, subarachnoid hemorrhage, and intracerebral hemorrhage. Cerebral thrombosis and cerebral embolism, known as ischemic strokes, are caused by blood clots that block an artery supplying the brain, either in the brain itself or in the neck. They account for 7080% of all strokes. Subarachnoid hemorrhage and intracerebral hemorrhage are hemorrhagic strokes that occur when a blood vessel bursts around or in the brain, either from trauma or excess internal pressure. Hypertension (high blood pressure) and atherosclerosis are usually contributing factors in these types of strokes.

CEREBRAL THROMBOSIS. Cerebral thrombosis, the most common type of stroke, occurs when a blood clot, or thrombus, forms within the brain itself, blocking blood flow through the affected vessel. This is usually due to atherosclerosis (hardening) of brain arteries, caused by a buildup of fatty deposits inside the blood vessels. Cerebral thrombosis occurs most often at night or early in the morning, and is often preceded by a TIA. Recognizing the occurrence of a TIA, and seeking immediate treatment, is an important step in stroke prevention.

CEREBRAL EMBOLISM. Cerebral embolism occurs when a blood clot from elsewhere in the circulatory system breaks free. If it becomes lodged in an artery supplying the brain, either in the brain or in the neck, it can cause a stroke. The most common cause of cerebral embolism is atrial fibrillation, which occurs when the upper chambers (atria) of the heart beat weakly and rapidly, instead of slowly and steadily. Blood within the atria does not empty completely, and may form clots that can then break off and enter the circulation. Atrial fibrillation is a factor in about 15% of all strokes, but this risk can be dramatically reduced with daily use of anticoagulant medication (such as Heparin or Coumadin).

SUBARACHNOID HEMORRHAGE. In this type of stroke, blood spills into the subarachnoid space between the brain and cranium. As fluid builds up, pressure on the brain increases, impairing its function. Hypertension is a frequent cause of these types of stroke, but vessels with preexisting defects, such as an aneurysm, are also at risk for rupture. Aneurysms are most likely to burst when blood pressure is highest, and controlling blood pressure is an important preventive strategy. Subarachnoid hemorrhages account for about 7% of all strokes.

INTRACEREBRAL HEMORRHAGE. Representing about 10% of all strokes, intracerebral hemorrhage affects vessels and tissue within the brain itself. As with subarachnoid hemorrhage, bleeding deprives affected tissues of blood supply, and the accumulation of fluid within the inflexible skull creates pressure on the brain that can quickly become fatal. Despite this, recovery may be more complete for a person who survives hemorrhage than for one who survives a clot, because the effects of blood deprivation are usually not as severe.

Risk factors

Risk factors for stroke involve:

  • Age and sex the risk of stroke increases with age, doubling for each decade after age 55. Men are more likely to have a stroke than women.
  • Heredity People with a family history of stroke have an increased risk of stroke themselves. In addition, African-Americans, Asians, and Hispanics all have higher rates of stroke than whites, related partly to higher blood pressure.
  • Diseases People with diabetes, heart disease (especially atrial fibrillation), high blood pressure, or prior stroke are at greater risk for stroke. Patients with one or more TIAs have ten times the risk.
  • Other medical conditions Stroke risk increases with obesity , high blood cholesterol, or high red blood cell count.
  • Lifestyle choices Stroke risk increases with cigarette smoking (especially if combined with the use of oral contraceptives), a sedentary lifestyle, alcohol consumption above two drinks per day, and/or the use of cocaine or intravenous drugs.

Symptoms

Knowing the symptoms of stroke is as important as knowing those of a heart attack. Patients with stroke symptoms should seek emergency treatment without delay, which may mean dialing 911 rather than their family physician. Specific symptoms of a stroke depend on the type, but all types share some characteristics in common.

An embolic stroke usually comes on quite suddenly and is intense right from the start, while symptoms of a thrombotic stroke come on more gradually. Symptoms for these ischemic strokes may include:

  • blurring or decreased vision in one or both eyes
  • severe headache, often described as "the worst headache of my life"
  • weakness, numbness, or paralysis of the face, arm, or leg, usually confined to one side of the body
  • dizziness, loss of balance or coordination, especially when combined with other symptoms

Hemorrhagic strokes are somewhat different. An intracranial hemorrhage exhibits any or all of the following symptoms:

  • loss of consciousness
  • altered mental state
  • seizure
  • vomiting or severe nausea
  • extreme hypertension
  • weakness, numbness, or paralysis, especially on one side of the body
  • sudden, severe headache

Symptoms of a subarachnoid hemorrhage include:

  • severe headache that begins suddenly
  • nausea or vomiting
  • stiff neck
  • light intolerance
  • loss of consciousness

Demographics

Each year, more than half a million people in the United States have a stroke. It is the third leading cause of death, killing about a third of its victimsapproximately 150,000 Americans each year. For those that survive, stroke is the leading cause of disability. Two-thirds of all strokes occur in people over age 65, with men more affected than women, although women are more likely to die from a stroke. African-Americans suffer strokes more often than whites, and are more likely to be die from them as well. This may be because African-Americans tend to suffer from hypertension more frequently than other groups.

Diagnosis

Diagnosing a stroke begins with a careful medical history, especially concerning the onset and distribution of symptoms, presence of risk factors; in this way other possible causes are excluded. A brief neurological exam is performed to identify the degree and location of any deficits, such as weakness, lack of coordination, or vision loss.

Once stroke is suspected, imaging technology is used to determine what type the patient has suffereda critical distinction that guides therapy. A noncontrast computed tomography scan (CT scan) can reliably identify hemorrhagic strokes, caused by uncontrolled bleeding in the brain. Magnetic resonance imaging (MRI), on the other hand, particularly diffusion-weighted imaging, can detect ischemic strokes, caused by blood clots, earlier and more reliably than CT scanning.

Blood and urine tests are also run to look for possible abnormalities. Other investigations that may be performed to guide treatment include electrocardiogram, angiography, ultrasound, and electroencephalogram.

Treatment

When brain cells die during a stroke, they release toxic chemicals that can trigger a chain reaction that can injure or kill other nearby cells. Damage from stroke may be significantly reduced by emergency treatment, and is a significant factor in how fully a patient will recover.

Emergency treatment

Emergency treatment of an ischemic stroke attempts to dissolve the clot. This "thrombolytic therapy" is performed most often with tissue plasminogen activator (t-PA), which must be administered within three hours of the stroke event. (Patients who awaken with stroke symptoms are ineligible for this type of therapy, since the time of onset cannot be reliably determined.) t-PA therapy has been shown to improve recovery and decrease long-term disability in patients. It carries a 6.4% risk of inducing a cerebral hemorrhage, however, and is not appropriate for patients with bleeding disorders, very high blood pressure, known aneurysms, any evidence of intracranial hemorrhage, or incidence of stroke, head trauma, or intracranial surgery within the past three months. Patients with clot-related stroke who are ineligible for t-PA treatment may be treated with heparin or other blood thinners, or with aspirin or other anticlotting agents in some cases.

Emergency treatment of hemorrhagic stroke is aimed at controlling intracranial pressure that accompanies these types of strokes. New surgical techniques can effectively relieve the pressure, especially when begun soon after the stroke event occurs. Surgery for hemorrhage due to aneurysm may be performed if the aneurysm is close enough to the cranial surface to allow access. Ruptured vessels are closed off to prevent rebleeding. For aneurysms that are difficult to reach surgically, endovascular treatment, in which a catheter is guided from a larger artery up into the brain to reach the aneurysm, may be effective. Small coils of wire are discharged into the aneurysm, which plug it up and block off blood flow from the main artery.

Rehabilitation

Rehabilitation refers to a comprehensive program designed to regain as much function as possible and compensate for permanent losses. Approximately 10% of stroke survivors are without any significant disability and able to function independently. Another 10% are so severely affected that they must remain institutionalized for severe disability. The remaining 80% can return home with appropriate therapy, training, support, and care.

Rehabilitation is coordinated by a team of medical professionals and may include the services of a neurologist, a physician who specializes in rehabilitation medicine, a physical therapist, an occupational therapist, a speech-language pathologist, a nutritionist, a mental health professional, and a social worker. Rehabilitation services may be provided in an acute care hospital, rehabilitation hospital, long-term care facility, outpatient clinic, or at home.

The rehabilitation program is based on the patient's individual deficits and strengths. Strokes on the left side of the brain primarily affect the right half of the body, and vice versa. In addition, in left brain-dominant people, who constitute a significant majority of the population, left-brain strokes usually lead to speech and language deficits, while right-brain strokes may affect spatial perception. Patients with right-brain strokes may also deny their illness, neglect the affected side of their body, and behave impulsively.

Rehabilitation may be complicated by cognitive losses, including diminished ability to understand and follow directions. Poor results are more likely in patients whose strokes left them with significant or prolonged cognitive changes, sensory losses, language deficits, or incontinence.

PREVENTING COMPLICATIONS. Rehabilitation begins with prevention of medical complications, including stroke recurrence, using many of the same measures used to prevent stroke, such as smoking cessation and getting hypertension under control.

One of the most common medical complications following stroke is deep venous thrombosis, in which a clot forms within a limb immobilized by paralysis. Clots can also become lodged in an artery feeding the lungs, a condition called pulmonary embolism, that is a common cause of death in the weeks following a stroke. Resuming activity within a day or two after the stroke is an important preventive measure, along with use of elastic stockings on the lower limbs. Drugs that prevent clotting may also be given, including intravenous heparin and oral warfarin.

Weakness and loss of coordination of the swallowing muscles may impair swallowing (dysphagia), and allow food to enter the lower airway. This may lead to aspiration pneumonia, another common cause of death shortly after a stroke. Dysphagia may be treated with retraining exercises and temporary use of pureed foods.

Other medical complications include urinary tract infections, pressure ulcers, falls, and seizures . Not surprisingly, depression occurs in 3060% of stroke patients; its severity is usually related to the level of permanent functional impairment It can be treated with anti-depressants and psychotherapy .

TYPES OF REHABILITATIVE THERAPY. Brain tissue that dies in a stroke cannot regenerate. In some cases, however, rehabilitation training can help other brain regions perform the same functions of that tissue. In other cases, compensatory actions may be developed to replace lost abilities.

Physical therapy is used to maintain and restore range of motion and strength in affected limbs, and to maximize mobility in walking, wheelchair use, and transferring (from wheelchair to toilet or from standing to sitting, for instance). The physical therapist advises patients on mobility aids such as wheelchairs, braces, and canes. In the recovery period, a stroke patient may develop muscle spasticity and contractures (abnormal muscle contractions) that can be treated with a combination of stretching and splinting.

Occupational therapy improves self-care skills such as feeding, bathing, and dressing, and helps develop effective compensatory strategies and devices for activities of daily living. A speech-language pathologist focuses on communication and swallowing skills. When dysphagia is a problem, a nutritionist can advise alternative meals that provide adequate nutrition.

Psychological therapy can help treat depression or loss of thinking (cognitive) skills. A social worker may help coordinate services and ease the transition out of the hospital back into the home. Both social workers and mental health professionals help counsel the patient and family during the difficult rehabilitation period. Caring for a person affected with stroke requires a new set of skills and adaptation to new demands and limitations. Home caregivers may develop stress , anxiety, and depressioncaring for the caregiver is an important part of the overall stroke treatment program. Support groups can provide an important source of information, advice, and comfort for stroke patients and caregivers; joining one can be an important step in the rehabilitation process.

Prognosis

Stroke is fatal for about 27% of white males, 52% of African-American males, 23% of white females, and 40% of African-American females. Stroke survivors may be left with significant deficits. Emergency treatment and comprehensive rehabilitation can significantly improve both survival and recovery.

Prevention

The risk of stroke can be reduced through lifestyle changes:

  • stop smoking
  • control blood pressure
  • get regular exercise
  • maintain a healthy weight
  • avoid excessive alcohol consumption
  • get regular checkups and follow the doctor's advice regarding diet and medicines

Use of high-estrogen dose oral contraceptives increase the chances for developing stroke, particularly in women who smoke and/or who are over 35. Currently, there are low-estrogen dose oral contraceptives, for which a clear relationship with stroke development is unclear.

Treatment of atrial fibrillation may also significantly reduce the risk of stroke. Preventive anticoagulant therapy may benefit those with untreated atrial fibrillation. Warfarin (Coumadin) has proven to be more effective than aspirin for those with higher risk.

Screening for aneurysms may be an effective preventive measure in those with a family history of aneurysms or autosomal polycystic kidney disease, which tends to be associated with aneurysms.

Resources

BOOKS

Caplan, L. R., M. L. Dyken, and J. D. Easton. American Heart Association Family Guide to Stroke Treatment, Recovery, and Prevention. New York: Times Books, 1996.

Duthie, Edmund H., Jr. Practice of Geriatrics. 3rd Edition. Philadelphia: W. B. Saunders, 1998: 328-335.

Goetz, Christopher G., and others. Textbook of Clinical Neurology. 1st edition. Philadelphia: W. B. Saunders, 1999: 909-911.

Warlow, C. P., and others. Stroke: A Practical Guide to Management. Boston: Blackwell Science, 1996.

PERIODICALS

Krishnan, K. Ranga Rama. "Depression as a contributing factor in cerebrovascular disease." American Heart Journal 140 (October 2000): 563.

ORGANIZATIONS

American Heart Association and American Stroke Association. 7272 Greenville Ave. Dallas, TX 75231.(214) 373-6300. <http://www.americanheart.org>.

National Stroke Association. 9707 E. Easter Lane, Englewood, Co. 80112. (800) 787-6537. <http://www.stroke.org>.

Laith Farid Gulli, M.D. Bilal Nasser, M.D.

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Gulli, Laith Farid; Nasser, Bilal. "Stroke." Gale Encyclopedia of Mental Disorders. 2003. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

Gulli, Laith Farid; Nasser, Bilal. "Stroke." Gale Encyclopedia of Mental Disorders. 2003. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1G2-3405700372.html

Gulli, Laith Farid; Nasser, Bilal. "Stroke." Gale Encyclopedia of Mental Disorders. 2003. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3405700372.html

Stroke

Stroke

Definition

Stroke is the common name for the injury to the brain that occurs when the flow of blood to brain tissue is interrupted by a clogged or burst artery. Arterial blood carries oxygen and nutrition to the cells of the body. When arteries are unable to carry out this function due to rupture, constriction, or obstruction, the cells nourished by these arteries die. The medical term for stroke is the acronym CVA, or cerebral vascular accident. It is estimated that four of every five families in the United States will be affected by stroke in their lifetime, and it is the top cause of adult disability worldwide. Stroke is ranked third in the leading causes of death in the United States, has left three million Americans permanently disabled, and costs the United States 30 billion dollars each year in terms of health care costs and lost productivity.

The most common type of stroke is classified as ischemic, or occurring because the blood supply to a portion of the brain has been cut off. Ischemic strokes account for approximately 80% of all strokes, and can be further broken down into two subtypes: thrombotic, also called cerebral thrombosis; and embolic, termed cerebral embolism.

Thrombotic strokes are by far the more prevalent, and can be seen in nearly all aging populations worldwide. As people grow older, atherosclerosis , or hardening of the arteries, occurs. This results in a buildup of a waxy cholesterol-laden substance in the arteries, which eventually narrows the interior space, or lumen, of the artery. This arterial narrowing occurs in all parts of the body, including the brain. As the process continues, the occlusion, or shutting off of the artery, eventually becomes complete, so that no blood supply can pass through. Usually the presentation of the symptoms of a thrombotic stroke are much more gradual and less dramatic than that of other strokes due to the slow ongoing process that produces it. Transient ischemic attacks, or TIAs, are one form of thrombotic stroke, and usually the least serious. TIAs represent the blockage of a very small artery or arteriole, or the intermittent or temporary obstruction of a larger artery. This blockage affects only a small portion of brain tissue and does not leave noticeable permanent ill effects. These transient ischemic attacks last only a matter of minutes, but are a forewarning that part of the brain is not receiving its necessary supply of blood, and thus oxygen and nutrition. Thrombotic strokes account for 40-50% of all strokes.

Embolic strokes are more acute and rapid in onset. They take place when the heart's rhythm is changed for a number of different reasons, and blood clot formation occurs. This blood clot can move through the circulatory system until it blocks a blood vessel and stops the blood supply to cells in a specific portion of the body. If it occludes an artery that nourishes heart muscle, it causes myocardial infarction, or heart attack . If it blocks off a vessel that feeds brain tissue, it is termed an embolic stroke. Embolisms account for 25-30% percent of all strokes. Normally these blockages occur in the brain itself when arteries directly feeding portions of brain tissue are blocked by a clot. But occasionally the obstruction is found in the arteries of the neck, especially the carotid artery.

Approximately 20% of cerebral vascular accidents are termed hemorrhagic strokes. Hemorrhagic strokes occur when an artery to the brain has a weakness and balloons outward, producing what is called an aneurysm. Such aneurysms often rupture due to this inflation and thinning of the arterial wall, causing a hemorrhage in the affected portion of the brain.

Both ischemic and hemorrhagic strokes display similar symptoms, depending on which portion of the brain is cut off from its supply of oxygen and nourishment. The brain is divided into left and right hemispheres. These hemispheres are responsible for bodily movement on the opposite side of the body from the brain hemisphere. For example, the left hemisphere of the brain is responsible for both motor control and sensory discrimination for the

right side of the body, just as the right hemisphere is responsible for left body movements and feeling. Deeper brain tissue in the left hemisphere of the brain directs muscle tone and coordination for both the right arm and leg. As the communication and speech centers for the brain are also located in the left hemisphere of the brain, interruption of blood supply to that area can also typically affect the person's ability to speak.

Description

Strokes are always considered a medical emergency, and every minute is important in initiating treatment. With the possible exception of transient ischemic attacks, all other types of stroke are life-threatening events. Stroke is a leading cause of death in all nations of the Western world and the more affluent Asian countries. One-quarter of all strokes are fatal. Cerebral vascular accidents are typically a condition of the elderly, and more often happen to men than women. In the United States, strokes occur in roughly one of every 500 people, and the likelihood of becoming a stroke victim rises sharply as a person ages. The incidence of strokes among people ages 30-60 years is less than 1%. This figure triples by the age of 80 years.

Causes & symptoms

Along with the typical risk factors for heart disease, the most common risk factor for thrombotic stroke is age. Some buildup of material along the inner lumen

of the artery, or atherosclerosis, is a normal part of growing older. Hypertension , or high blood pressure, can result from this buildup, as the heart attempts to pump blood through these narrowed arteries. High blood pressure is one of the foremost causes of stroke. Aside from aging and hypertension, heart disease, obesity , diabetes, smoking , oral contraceptives in women, polycythemia, and a condition called sleep apnea are all risk factors for stroke, as is a diet high in cholesterol or fatty foods.

The risk factors for hemorrhagic stroke are those that can weaken arteries supplying blood to the brain. They include high blood pressure, which can over a period of time cause the ballooning of arteries known as aneurysm, and hereditary malformations that produce defective and weakened veins and arteries. Substance abuse also is a major cause. It has been demonstrated for years that cocaine and stimulants such as amphetamine drugs are culprits, and chronic alcoholism can cause a weakening of blood vessels that also can result in hemorrhagic stroke.

Exactly what triggers the actual ischemic stroke event continues to puzzle clinicians. Researchers refer to these triggers as "short-term risk" vs. "long-term risk" factors. If researchers can help identify the triggers for stroke in those with high risk factors, they might be able to help prevent the stroke from occurring. One 2002 report found that abrupt changes in body position caused by sudden loud noises or other unexpected events might trigger a stroke. These events occurred during a two-hour period before the stroke. As noted previously, the symptoms of stroke observed depend upon the part of the brain that is affected, and how large a portion of brain tissue has been damaged by the CVA. Unconsciousness and even seizures can be initial components of a stroke. Other effects materialize over a time period ranging from minutes to hours, and even, in some rare instances, over several days. Headache (often described as "the worst headache I've ever had" in hemorrhagic stroke); mental confusion; vertigo; vision problems, aphasia, or difficulty speaking and communicating, including slurring of words are major symptoms. Hemiplegia, or weakness or paralysis of one side of the body, is a symptom that is frequently seen. This one-sided weakness is often first noticed in the person's face. Stroke victims often have facial drooping, or slackness of the facial muscles on the affected side, as well as difficulty swallowing. The severity of these symptoms will depend upon the amount of brain tissue that has died and its location in the brain.

Computed tomography (CT) brain scans, angiography, lumbar puncture, and magnetic resonance imaging (MRI) are all used to rule out any other possible causes of the symptoms seen. Other possible causes of these symptoms could be brain tumor, brain abscess , subdural hematoma, encephalitis, and meningitis .

Treatment

There are many applications of alternative and complementary medicine in the treatment and prevention of stroke. Alternative therapies are also used in rehabilitation of stroke victims. Acupuncture and acupressure are commonly used for stroke patients, as is massage. Movement and meditation programs such as t'ai chi are also helpful. Herbs with antioxidant properties may be prescribed by a practitioner. Many therapies aid in blood pressure control, including meditation, guided imagery, biofeedback and t'ai chi.

Allopathic treatment

Much of the needed care immediately following a stroke will be to prevent damage beyond that which has already occurred. Paralysis requires prevention of contractures or tightening up of paralyzed limbs. This is done through physiotherapy, and may include the use of supportive braces for arms or hands, footboards or wearing sneakers when in bed to prevent foot drop. The severely ill stroke patient will need to be repositioned frequently to prevent complications such as pneumonia and venous or pulmonary embolism.

Because of difficulty in swallowing, the person who has suffered a stroke may need a temporary or permanent feeding tube inserted into the stomach to ensure adequate nutrition. Such tubes can be placed through the nose, into the esophagus, and into the stomach, or gastrically, with a wider-lumen tube surgically implanted into the stomach.

A severe stroke that results in coma or unconsciousness will require medical monitoring and support, including oxygen and even possibly intubation to assure an adequate airway and facilitate breathing. Provision of fluids that the person may not be able to take by mouth due to swallowing difficulties will be necessary, as will possibly the administration of such blood-thinning or clot-dissolving medications as Coumadin or heparin. A five-year clinical trial completed in 1995 and reported by the New England Journal of Medicine showed that stroke patients treated with t-PA, a clot-dissolving medication, within three hours of the stroke were one-third more likely to be left with no permanent residual difficulty. The trauma of the brain caused by stroke may result in edema , or swelling, which may have to be reduced by giving the patient diuretic or steroid medications. Sometimes surgical removal of a clot obstructing an artery is necessary. Hemorrhagic stroke can cause a buildup of pressure on the brain that must be relieved as quickly as possible to prevent further brain damage. In extreme cases, this may require incision through the skull to relieve that pressure.

Expected results

Studies reported by the National Institute of Neurological Disorders and Stroke report that 25% of people who suffer a stroke recover completely and 20% die within three months after the stroke. Of the remaining 55% percent, 5% will require long-term (nursing home) care, and for the rest roughly half of all stroke patients rehabilitative and restorative services will be necessary to regain as much of their former capabilities as possible. It has been estimated that the most common irreversible damage from stroke is the loss of intellectual functions.

Prevention

Control of blood pressure is the single most important factor in preventing stroke. People should have their blood pressure checked regularly, and if consistently elevated, (diastolic, or lower blood pressure beat above 90 to 100, systolic or top beat above 140 to 150), a physician should be consulted.

The American Heart Association recommends that cigarette smokers break the habit to reduce stroke risk. Current cigarette use can increase risk of cerebral infarction to nearly double, and smoking is associated with other risk factors of stroke. The AHA also recommends that those at risk for stroke avoid secondhand tobacco smoke if possible.

Diet, including reduction of sodium (salt) intake, exercise and weight loss, if overweight, are all non-drug treatments for lowering blood pressure. Other natural remedies include eating artichokes, which lowers the fat content of the blood; garlic , now believed to lower cholesterol and blood pressure as well as to reduce the clotting ability of the blood; and ginkgo, which improves circulation and strengthens arteries and veins. The use of folic acid, lecithin , vitamins B 6 and B12, vitamins C and E are all recommended as supportive measures in reducing blood pressure. Two new Harvard studies found that eating a diet high in fruits and vegetables (particularly leafy green vegetables and cruciferous ones like broccoli, cauliflower, and cabbage) can reduce the risk of ischemic stroke. When fruits and vegetables were not only added to the diet, but replaced meat and trans fats, they further reduced stroke risk.

Avoiding substances that can cause stroke is another preventive measure. A 2002 report revealed that the popular herbal supplement ephedrine can cause stroke, heart attack, and sudden death.

Multiple studies have found that aspirin acts as a blood-thinning or clot-reducing medication when taken in small doses. One baby aspirin tablet per day provides this anticoagulant protection.

If necessary, a physician may also order medication to lower blood pressure. These medications include the following categories of drugs:

  • Beta blockers reduce the force and speed of the heartbeat.
  • Vasodilators dilate the blood vessels.
  • Diuretics reduce the total volume of circulating blood and thus the heart's work by removing fluid from the body.
  • Lipid-lowering drugs increase the loss of cholesterol from the body or prevent the conversion of fatty acids to cholesterol. This lowers fat levels in the blood stream.

A preliminary report out of France in 2002 stated that getting a flu shot might reduce risk of stroke. Previous research has also suggested that flu shots might stimulate a response in the immune system that helps reduce inflammation throughout the body. If true, those most likely to benefit would be people age 75 and older.

Resources

BOOKS

Clayman, Charles B., MD. The American Medical Association Home Medical Encyclopedia. New York: Random House, 1989.

Landis, Robyn, and Karta Purkh Singh Khalsa. Herbal Defense: Positioning Yourself to Triumph Over Illness and Aging. New York: Warner Books, 1997.

Sammons, James H., MD, John T. Baker, MD, Frank D. Campion, Heidi Hough, James Ferris, Brenda A. Clark. The American Medical Association Guide to Prescription and Over-the-Counter Drugs. New York: Random House, 1988.

Thomas, Clayton L. Taber's Cyclopedic Medical Dictionary. F.A. Davis Co., 1998.

PERIODICALS

"Abrupt Changes in Body Position Can Trigger Stroke." Heart Disease Weekly (March 24, 2002):15.

"Flu Shots May Prevent Strokes." Medical Update (February 2002):5.

Hall, Zach W., Ph.D. New England Journal of Medicine (December 14, 1995).

Samenuk, David. "Adverse Cardiovascular Events Temporarily Associated with Ma Huang, an Herbal Source of Ephedrine." JAMA, Journal of the American Medical Association (March 27, 2002):1506.

"Strategies Identified to Prevent Primary Stroke." Clinician Reviews (March 2002):89.

"Vegetables and Fruits Cut Stroke Risk." Health Science (Winter 2002):7.

ORGANIZATIONS

National Institute of Neurological Disorders and Stroke. National Institutes of Health, Building 31, Room 8A-16, P.O. Box 5801, Bethesda, MD 20824. (301) 496-5751.

National Stroke Association. 1-800-STROKES. http://www.stroke.org.

OTHER

Dr. Rappa. "What Is a Stroke?" http://www.medhealthsolution.com.

Joan Schonbeck

Teresa G. Odle

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Schonbeck, Joan; Odle, Teresa. "Stroke." Gale Encyclopedia of Alternative Medicine. 2005. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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Stroke

STROKE

Stroke, or cerebrovascular accident (CVA), is the third leading cause of death (after heart disease and cancer) in the United States and the industrialized countries of the world. The term "stroke," which comes from subjects being suddenly "struck down" with neurological deficits, is commonly used by both professional and lay groups. Efforts are being made to replace the term with "brain attack" to dramatize its analogous effects to a "heart attack," the term used for myocardial infarction. The term "cerebrovascular accident" is used interchangeably with stroke ("accident" indicates the catastrophic nature of strokes, not a traumatic origin as the term implies). More than 600,000 strokes occur annually in the United States, according to the American Heart Association, and stroke prevalence (number of living stroke victims) is approximately 4.5 million with an annual cost in 1997, both direct and indirect, of over $40 billion.

Stroke refers to the usually sudden onset of a neurological deficit, such as hemiparesis (weakness on one side of the body), or aphasia (impairment of language comprehension and production), which can be attributed to either the occlusion or rupture of a cerebral vessel. Resulting specific neurological symptoms and signs are determined by the area of the brain that is affected, and since the complex functions of the brain are either localized in specialized areas or diffusely distributed, stroke symptoms may similarly be localized or generalized in nature. For example, the long pathway of motor fibers can be interrupted, with resulting hemiparesis involving various cerebral arteries or their branches, such as the anterior, middle, or vertebrobasilar arteries. Occlusion of smaller arterioles which feed smaller areas of brain may result in more isolated effects, such as pure sensory or motor hemiparesis. On the other hand, occlusion or rupture of vessels in "silent" areas of the brain, as in the frontal or parietal cortex, can lead to subtle nonfocal symptoms reflected in impaired cognition, executive function, or memory. Other symptoms of impaired specialized brain functions from strokes include apraxia (impairment in the execution of motor actions), and agnosia (loss of ability to recognize familiar objects). Leukoaraiosis, or increased T2-signal intensity, on magnetic resonance imaging (MRI) of brain white matter results predominantly from small-vessel disease, and this syndrome is associated with increased risks for strokes and dementia.

ISCHEMIC STROKES

The causes of arterial occlusion, or ischemic strokes, are multiple. The most frequent is atherosclerotic disease of extracranial and/or intracranial arteries; the former is more common in Caucasians, while the latter is more frequent among African Americans and Asians. A thrombus (stationary blood clot) formed on atherosclerotic plaques in these locations, as well as on the aorta, can dislodge and embolize to occlude a distal artery. Strokes due to atherosclerosis account for approximately two-thirds of all strokes. If seen within three hours of stroke onset, treatment with tissue plasminogen activator (tPA), a thrombolytic agent, may substantially improve a patient's neurological outcome. Otherwise, therapeutic efforts are aimed at optimizing cerebral blood flow to ischemically impaired brain tissue, providing neural protection to avert brain damage, and maximizing neurorehabilitation. Research on stem cell and neural progenitor cell implantation into an ischemically damaged brain to promote recovery is a recently promising area of stroke research.

Transient Ischemic Attacks (TIAs). Strokes may be heralded by transient neurological deficits, called transient ischemic attacks (TIAs), such as temporary blindness of one eye (amaurosis fugax), hemiparesis, or aphasia. Most frequently, TIAs occur with significant atherosclerotic disease of the extracranial carotid arteries. Control of risk factors for atherosclerosis, such as hypertension, smoking, diabetes mellitus, elevated cholesterol, stress, and, perhaps, sedentary lifestyle, will hopefully minimize strokes from this cause to an irreducible minimum. For significant extracranial disease (>70% diameter stenosis [constriction] at the carotid bifurcation), carotid endarterectomy in competent surgical hands has been shown to reduce stroke recurrence significantly. Aspirin and other antiplatelet drugs in nonsurgical candidates can prevent subsequent strokes.

Cardiogenic strokes. Ischemic strokes can be caused by emboli from the heart as a result of more than a dozen cardiac disorders, the most common being arrhythmias, particularly atrial fibrillation (AF). Suspected cardiogenic strokes require workup, including transthoracic and transesophageal echocardiography (TTE and TEE), which can detect valvular pathologies, wall-motion abnormalities, thrombi, and patent foramen ovale (PFO). This group, in aggregate, may account for up to a quarter or more of all ischemic strokes. For AF, the treatment of choice to prevent embolic strokes is long-term anticoagulation. Patients who are not anticoagulation candidates should be treated with antiplatelet drugs. Conditions such as PFO can be treated medically with anticoagulation; surgical and percutaneous options are also available for PFO closure.

Lacunar Strokes. These strokes refer to small branch occlusions (noted previously), and include discrete syndromes such as pure sensory and motor hemiparesis. Lacunar strokes result primarily from chronic sustained hypertension, and the pathological change is "lipohyalinosis" of arterioles. This syndrome may account for 10 to 15 percent of all strokes. Adequate control of hypertension should prevent this condition.

Two final categories of diseases-causing ischemic strokes are more frequently considered in younger persons, especially those under fifty-five years of age, and involve arteries and blood elements. For the former, vessel diseases other than atherosclerosis include inflammatory processes, such as the arteritides; migraine; dissectioneither spontaneous or traumatic; moyamoya syndrome; fibromuscular disorders; MELAS syndrome (mitochondrial encephalopathy, lactic acidosis, and stroke-like symptoms) and a few others. For the latter, blood-element disorders include clotting, and platelets and erythrocyte abnormalities. The most common clotting disorders are resistance to protein C activationmost frequently due to Factor V Leiden mutation (506Q); antiphospholipid syndrome, which includes the lupus anticoagulant and anticardiolipin antibodies; reduced antithrombin III; protein C & S deficiencies; plus a few others. Treatment of vascular disorders is tailored to the individual condition; for example, migraine is treated with prophylactic agents, which prevent vasospasm; arteritides with steroids and immunosuppressive agents; and moyamoya syndrome with a variety of bypass surgical procedures. Many of the hypercoagulable or prothrombotic conditions are treated with long-term anticoagulation.

INTRACEREBRAL AND SUBARACHNOID HEMORRHAGES

Rupture of vessels include two large categories. The more common is intracerebral hemorrhage (ICH), which results from chronic sustained hypertension and accounts for approximately 10 percent of all strokes. An infrequent cause of ICH is amyloid angiopathy; its cause (and cure) is unknown. A second category of vessel rupture is subarachnoid hemorrhage (SAH), most frequently due to aneurysmal rupture, but occasionally from arteriovenous malformations. SAH accounts for about 5 percent of all strokes. Gene and molecular pathological markers to identify persons at risk will hopefully provide interventional tools to both prevent and treat subjects at risk before aneurysmal rupture.

ICH occurs in five brain sites, most commonly in the putamen. With substantial cerebellar ICH in a noncomatose patient, surgical evacuation can be life-saving. The only other site that may benefit from surgery is polar or white matter ICH. In neurologically viable patients, SAH can be treated successfully with surgical extirpation of the aneurysm, or with a variety of endovascular procedures, such as aneurysmal obliteration.

PUBLIC HEALTH IMPORTANCE OF STROKES

As the third leading cause of death and disability, there are important public health implications for strokes, especially since many of the stroke syndromes are preventable. This is particularly true for those due to atherosclerosis, which is the most common cause of strokes. Except for increasing age, all of the risk factors for atherosclerosis can be either controlled or eliminated. To accomplish this goal, better strategies to educate and motivate the general public are vital.

In addition to controlling risk factors, a better understanding of the nature of stroke symptoms by the public is required for expeditious corrective and therapeutic measures, much as has happened with the public's general awareness of chest pain as a symptom of a potential heart attack. Investigations on proteomic and gene expression profiles for strokes to identify individuals at increased risk for strokes will hopefully provide public health planners with an even more powerful tool to intervene effectively for stroke prevention, the ultimate best treatment of strokes.

Frank Yatsu

(see also: American Heart Association; Atherosclerosis; Cardiovascular Diseases; Transient Ischemic Attacks )

Bibliography

Barnett, H. J. M.; Mohr, J. P.; Stein, B.; and Yatsu, F. M., eds. (1998). Stroke: Pathophysiology, Diagnosis & Management. Philadelphia, PA: Churchill-Livingstone.

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stroke

stroke Apoplexy or stroke has been recognized at least since the beginning of Western medicine, in ancient Greece. Stroke arises from injury to the brain caused by interruption of the blood supply, rather like a heart attack: in fact stroke is now sometimes called a ‘brain attack’. Over 250 000 people suffer some type of stroke in the UK each year. Stroke now is the third leading cause of death and the most common cause of adult disability.

The most typical manifestations include sudden weakness of the face, arm, or leg, and altered sensation or numbness, on the side of the body opposite the stroke. Language expression and comprehension can be impaired, usually for strokes in the left cerebral hemisphere. A stroke in the occipital lobe, at the back of the hemisphere, can cause blindness in the opposite half of the visual field. Sometimes a stroke in the parietal lobe of the right hemisphere renders the patient unable to attend to the left hand side of objects or even without awareness of the left side of their own body (the so-called neglect syndrome). Most bizarre of all, damage to the right hemisphere can produce anosagnosia — denial by the patient of any deficit at all, despite virtual paralysis of the left arm and leg.

The brain — especially the cerebral cortex, a frequent target of strokes — is divided into distinct regions, functionally specialized for one sense or another, for the control of movement, for aspects of language, etc. The sensory, motor, linguistic, and cognitive deficits caused by small strokes can therefore be extraordinarily specific, and their interpretation by neuropsychologists has been a major source of evidence about the organization of the human brain. But major strokes can have devastating effects, sometimes eliminating consciousness completely, or, perhaps even worse, leaving a conscious mind in a useless body. The French writer Jean-Dominique Bauby gives a unique view of this state in his autobiography — paralysed except for the capacity to blink an eye, he described himself as a ‘butterfly’ trapped inside a ‘diving bell’.

In 1761, Battista Morgagni, Professor of Anatomy in Padua, first clearly attributed strokes to limitation of blood flow to the brain. In 85% of cases this comes from blockage of a blood vessel giving a so-called ischaemic stroke. Most of the remaining 15% are due to sudden bleeding into the substance of the brain to create a haemorrhagic stroke. A small percentage are due to rupture of an artery in the surface of the brain — a subarachnoid haemorrhage.

The brain is metabolically highly active. Although it accounts for only about 2% of the body weight, it uses 20% of the total oxygen intake and has a high demand for the blood sugar, glucose. At least 15% of the blood output from the heart is needed to supply this amount of oxygen and glucose. If this blood flow is interrupted, even for minutes, then brain cells die. The pattern of clinical deficits after strokes (other than subarachnoid haemorrhage) is determined by the particular blood vessel that is primarily affected. Interruption of flow in the left middle cerebral artery, for example, typically leads to specific impairments of language or calculation, while occlusion of the right middle cerebral artery may disturb visual–spatial skills. Subarachnoid haemorrhages lead to changes in pressure on the brain and chemical effects that cause more general deficits.

The most common cause of ischaemic strokes is blocking of a vessel by a so-called embolus, which forms on a pathologically abnormal wall of a larger vessel and then detaches and circulates in the blood. The wall of the larger vessel, particularly in areas of high-flow turbulence and around major bifurcations (e.g. the point at which the internal carotid artery branches off from the aorta), may become thickened and irregular, and calcified atherosclerotic plaques may form. Rupture of these plaques can form a blood clot, fragments of which can be carried along the course of flowing blood to block smaller vessels. Alternatively, platelets that aggregate on the abnormal surface of a plaque, or fragments of the plaque, can themselves act as emboli. Emboli also can be formed in the heart, or, more rarely, can come from elsewhere in the body.

The risk of stroke is determined by both genetic and environmental influences. A number of specific risk factors include: a family history of stroke in first-degree relatives; older age; male sex; hypertension; smoking; diabetes; and heart disease.

Control of risk factors (e.g. giving up smoking, control of hypertension or diabetes, treatment of heart disease) can reduce the risk of stroke in affected individuals. The importance of hypertension has been recognized in a practical way since the time of Galen (c. ad 130–210), who advocated treatment of apoplexy with vigorous blood-letting.

Perhaps half or more of strokes are preceded by neurological symptoms (such as difficulty with speech or with movement of one hand) that last less than 12 hours and reverse completely. However, the risk of a full-blown stroke following these transient ischaemic attacks (TIAs) is similar to the risk that a stroke leaving persistent deficits will be followed by another (approximately 12% overall risk over 12 months). The precise risks vary substantially, however, depending on the underlying cause and the particular blood vessel involved.

Acute treatment of smaller ischaemic strokes is generally based on use of drugs that limit platelet aggregation, such as aspirin. Patients with occlusion of relatively large vessels, who reach medical care within the first few hours after the onset of deficits, may benefit from infusion of thrombolytic agents (clot-busters) such as tissue plasminogen activator (tPA) that can dissolve emboli and restore blood flow in the ischaemic area. This may benefit particularly the tissue at the outside of the core of the damage, in the so-called ischaemic penumbra, where the function of brain tissue is not irreversibly impaired.

Patients who survive their strokes without massive neurological deficits always show significant functional improvement. This occurs most rapidly over the first month after the stroke, but can continue for two years or more. The degree of recovery depends not only on the size of a stroke but also on its location. For example, small ischaemic strokes in the basal ganglia — nuclei deep in the cerebral hemispheres, involved in the control of movement — have a much better prognosis than strokes in the posterior limb of the internal capsule (see brain), which contains major nerve fibres running between the cerebral cortex and the rest of the brain.

Recovery is often complicated by less well-understood consequences of stroke, which illustrate the complex interconnectedness of brain functions. Alfred Brodal, the famous Danish neuroanatomist, observed in 1973 after his own small, ‘pure motor’ stroke that, in addition to difficulties moving one half of his body, he suffered from a ‘loss of powers of concentration, reduced short-term memory, increased fatigue, reduced initiative, [and] incontinence of movements of emotional expression’. Depression can also be a major problem. In part this is a consequence of the patient's perception of the new disability. Sir Peter Medawar, Nobel Laureate in Medicine, describes this well in personal reflections on his own stroke entitled Memoirs of a Thinking Radish (1986). Strokes can have direct effects on the balance of neurotransmitters in the brain that are responsible for mood.

Current experimental strategies for treatment in stroke are focusing simultaneously on several areas: safer and more effective ways of delivering thrombolytic therapy to patients, with particular attention to the possibility of rapid, on-the-spot treatment; neuroprotective agents, designed to guard the surrounding area of brain from the effects of neurotransmitters released by dying neurons following the initial damage of the stroke; and other experimental drugs, directed at limiting damage from the breakdown of nerve cell membranes and highly reactive oxygen radicals that are generated in the damaged tissue.

An intriguing possibility is that cells derived from bone marrow (stem cells) could be implanted surgically into areas of brain damaged by stroke, where they may be able to differentiate into new neurons that could take over functions of those that have been damaged.

Paul M. Matthews

Bibliography

Bauby, J.- D. (1998). The diving-bell and the butterfly. Fourth Estate, London.
Kapur, N. (1997). Injured brains of medical minds. Oxford University Press.
Porter, R. (1999). The greatest benefit to mankind. Fontain Press, London.


See also apoplexy; brain; language and the brain; paralysis.

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COLIN BLAKEMORE and SHELIA JENNETT. "stroke." The Oxford Companion to the Body. 2001. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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COLIN BLAKEMORE and SHELIA JENNETT. "stroke." The Oxford Companion to the Body. 2001. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O128-stroke.html

Stroke

Stroke

As the third major cause of death and disability in America and the leading neurological disorder for morbidity, stroke is a major public health problem. The incidence of strokes is predicted to become worse as the percentage of the aging population, which is predominantly affected, increases. Stroke (or "brain attack") is defined as an acute neurological dysfunction, usually focal in nature, which can be explained by either occlusion of a feeding artery to the brain or the rupture of such a vessel.

Ischemic strokes result from blood clots that originate from more proximal arteries to the brain such as the carotid bifurcation in the neck or even from the heart. The neurological deficits with ischemic strokes depend upon several factorsone being the size of the clot. With large clots, larger arteries with a larger area of brain to feed will be affected, leading to greater neurological impairment. Second, the specific vessel(s) is occluded. If the artery to the speech area is occluded, the patient will be unable to talk, so-called aphasia; or if the artery to the area controlling arm and leg movements is occluded, the patient will become paralyzed on the opposite side. Third is the rapidity of artery occlusion. The cause of clot or thrombus formation is most commonly due to atherosclerotic disease or hardening of the arteries, but other conditions exist that make the blood clot, such as abnormal conditions causing the blood to be very sticky, or what is termed prothrombotic states. With vessel rupture, the two most common conditions are aneurysms, which lie primarily in the subarachnoid space surrounding the brain, and intracerebal hemorrhages, which most commonly result from longstanding uncontrolled hypertension. Other conditions associated with vessel rupture include abnormal formation of arteries and veins.

Strokes, like heart attacks, are most commonly caused by atherosclerosis or hardening of the arteries. The major risk factors for atherosclerosis are high blood pressure (hypertension), smoking, diabetes mellitus, increased lipids (hypercholesterolemia and hypertriglyceridemia), stress, sedentary lifestyle, and obesity. These risk factors are mostly treatable, and therefore greater public health programs to educate the general public are generally viewed by health care practitioners as a partial solution to the problem. Risk factors for less common hereditary conditions predisposing to vascular, cardiac, and thrombotic disorders that result in strokes require preventive intervention as well, with the most common treatment being the thinning of blood (also known as "anticoagulation"). Use of DNA analytical techniques to identify as a yet unknown combination of gene defects leading to strokes as well as a large number of proteins, which also in combination can lead to strokes, an area called proteomics promise to identify stroke-risk predisposition more precisely and at an earlier age.

In addition to knowing one's stroke risk factors, individuals should be aware of stroke symptoms so that urgent workup and appropriate treatment can be instituted, possibly reversing neurological deficits. For example, use of the thrombolytic agent (clot buster) tissue plasminogen activator (tPA) has been proven to be the first statistically significant drug to reverse the effects of a thrombus or embolus causing stroke symptoms. But because this treatment must be instituted within three hours of stroke onset, this short timeframe means that the public, the emergency services, and treating physicians must develop a rapidly responding medical system that can triage and treat patients quickly. Other stroke syndromes that can benefit from therapeutic intervention include intracerebral hemorrhages (bleeding) with surgical evacuation of the clot, particularly cerebellar hemorrhages, and subarachnoid hemorrhages due to berry aneurysms with surgical or interventional ablation of the aneurysm. Embolic strokes, especially from cardiac sources, such as rhythm abnormalities, particularly atrial fibrillation, are prone to cause embolic strokes, and these can be prevented with anticoagulation.

See also: Causes of Death

Bibliography

Barnett, Henry J. M., Jay P. Mohr, Bennett Stein, and Frank M. Yatsu eds. Strokes: Pathophysiology, Diagnosis, and Management, 3rd edition. Philadelphia: W. B. Saunders, 1998.

FRANK M. YATSU

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YATSU, FRANK M.. "Stroke." Macmillan Encyclopedia of Death and Dying. 2002. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3407200268.html

stroke

stroke / strōk/ • n. 1. an act of hitting or striking someone or something; a blow: he received three strokes of the cane. ∎  a method of striking the ball in sports or games. ∎  Golf an act of hitting the ball with a club, as a unit of scoring: won by two strokes. ∎  the sound made by a striking clock. 2. an act of moving one's hand or an object across a surface, applying gentle pressure: massage the cream into your skin using light upward strokes. ∎  a mark made by drawing a pen, pencil, or paintbrush in one direction across paper or canvas: the paint had been applied in careful, regular strokes. ∎  a line forming part of a written or printed character. ∎  a short printed or written diagonal line typically separating characters or figures. 3. a movement, esp. one of a series, in which something moves out of its position and back into it; a beat: the ray swam with effortless strokes of its huge wings. ∎  the whole motion of a piston in either direction. ∎  the rhythm to which a series of repeated movements is performed: the rowers sing to keep their stroke. ∎  a movement of the arms and legs forming one of a series in swimming. ∎  style of moving the arms and legs in swimming: front crawl is a popular stroke. ∎  (in rowing) the mode or action of moving the oar. ∎  (also stroke oar) the oar or oarsman nearest the stern of a boat, setting the timing for the other rowers. 4. a sudden disabling attack or loss of consciousness caused by an interruption in the flow of blood to the brain, esp. through thrombosis. • v. [tr.] 1. move one's hand with gentle pressure over (a surface, esp. hair, fur, or skin), typically repeatedly; caress: he put his hand on her hair and stroked it. ∎  [tr.] apply (something) to a surface using a gentle movement: she strokes blue eyeshadow on her eyelids. ∎ inf. reassure or flatter (someone), esp. in order to gain their cooperation: production executives were expert at stroking stars and brokering talent. 2. act as the stroke of (a boat or crew): he stroked Penn’s rowing eight to victory. 3. hit or kick (a ball) smoothly and deliberately: Miller calmly stroked three-pointers throughout the tournament. ∎  score (a run or point) in such a manner: the senior stroked a two-run single. PHRASES: at a (or one) stroke by a single action having immediate effect: attitudes cannot be changed at one stroke. not (or never) do a stroke of work do no work at all. on the stroke of —— precisely at the specified time: he arrived on the stroke of two. put someone off their stroke disconcert someone so that they do not work or perform as well as they might; break the pattern or rhythm of someone's work. stroke of business a profitable transaction. stroke of genius an outstandingly brilliant and original idea. stroke of luck (or good luck) a fortunate occurrence that could not have been predicted or expected.

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"stroke." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

"stroke." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1O999-stroke.html

"stroke." The Oxford Pocket Dictionary of Current English. 2009. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-stroke.html

stroke

stroke, destruction of brain tissue as a result of intracerebral hemorrhage or infarction caused by thrombosis (clotting) or embolus (obstruction in a blood vessel caused by clotted blood or other foreign matter circulating in the bloodstream); formerly called apoplexy. Cerebral hemorrhage or thrombosis occurs most often in elderly persons with constricted arteries (see arteriosclerosis), although either may also be caused by inflammatory or toxic damage to the cerebral blood vessels. Cerebral embolism may occur at any age, even in children.

Symptoms of stroke develop suddenly. In cases of severe brain damage there may be deep coma, paralysis of one side of the body, and loss of speech, followed by death or permanent neurological disturbances after recovery. If the brain damage sustained has been slight, there is usually complete recovery, but most survivors of stroke require extensive rehabilitation. Hypertension, which is a major cause of intracranial hemorrhage and stroke, can be treated by preventive measures using diet (e.g., increasing nutrients such as antioxidants and folate), drug therapy, and stress reduction techniques. Other preventive measures for people at high risk include daily aspirin to retard clot formation and surgical correction of the narrowed carotid artery. Sometimes surgical removal of the clot is possible on larger vessels, but it is usually pointless after the stroke or when blockage is widespread. The thrombolytic drug tissue plasminogen activator, widely used to treat heart attacks, has been approved for use within three hours of the onset of strokes caused by clots.

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"stroke." The Columbia Encyclopedia, 6th ed.. 2016. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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"stroke." The Columbia Encyclopedia, 6th ed.. 2016. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-stroke.html

Stroke

STROKE

DEFINITION


A stroke is the sudden death of cells in a limited part of the brain caused by a reduced flow of blood to the brain.

DESCRIPTION


Blood brings oxygen and nutrients to brain cells and also removes waste products from cells. A stroke occurs when blood flow is interrupted to part of the brain. Without blood, brain cells quickly begin to die. The effects of a stroke depend on the part of the brain affected. A stroke may cause paralysis, speech problems, loss of memory or reasoning ability, coma, or death.

More than half a million people in the United States experience a stroke each year. Stroke is the third leading cause of death in this country and the leading cause of disability. Two-thirds of all strokes occur in people over the age of sixty-five. They affect men more often than women, and blacks more often than whites.

Stroke is a medical emergency that requires immediate medical attention. The sooner treatment is received, the better the chances of survival. At one time, nine out of ten people died after a stroke. Because of improved treatment methods, less than three out of ten people who suffer a stroke die from the experience.

CAUSES


There are four main types of strokes. They are:

  • Cerebral thrombosis
  • Cerebral embolism
  • Subarachnoid hemorrhage
  • Intracerebral hemorrhage

Cerebral thrombosis and cerebral embolism account for about three-quarters of all strokes.

Cerebral thrombosis occurs when a blood clot forms inside the brain, stopping the flow of blood to or from the brain. The medical term for blood clot is thrombosis. The most common cause for the formation of a blood clot is the hardening of the arteries, or atherosclerosis (see atherosclerosis entry).

A cerebral thrombosis occurs most often at night or early in the morning. It is often preceded by a transient ischemic attack (TIA), which is also referred to as a mini-stroke. A TIA may act as a warning sign that a full stroke is likely to occur.

Cerebral embolism is also caused by a blood clot. The clot, however, forms elsewhere in the body then travels through the bloodstream to the brain. Once in the brain, it produces effects like those of cerebral thrombosis.

Subarachnoid hemorrhage and intracerebral hemorrhage are caused when blood vessels in the brain break. Blood vessels sometimes develop weak spots in their walls. These weak spots are called aneurysms (pronounced AN-yu-RIHZ-umz; see cerebral aneurysm entry). When an aneurysm breaks, blood flows out of the blood vessel into the surrounding tissue and brain cells begin to die rapidly. An intracerebral hemorrhage takes place inside the brain. A subarachnoid (pronounced sub-uh-RAK-noyd) hemorrhage occurs on the surface of the brain.

Stroke: Words to Know

Aneurysm:
A weak spot in a blood vessel that may break open and lead to a stroke.
Cerebral embolism:
Blockage of a blood vessel in the brain by a blood clot that originally formed elsewhere in the body and then traveled to the brain.
Cerebral thrombosis:
Blockage of a blood vessel in the brain by a blood clot that formed in the brain itself.
Intracerebral hemorrhage:
Bleeding that occurs within the brain.
Subarachnoid hemorrhage:
Bleeding that occurs on the surface of the brain.
Tissue plasminogen activator (tPA):
A substance that dissolves blood clots in the brain.

SYMPTOMS


The symptoms of a stroke caused by an embolism usually appear suddenly and are most intense right after the stroke occurs. With a thrombosis, the stroke comes on more slowly. In either case, symptoms include:

  • Blurring or decreased vision in one or both eyes
  • Severe headache, often described as "the worst headache of my life"
  • Weakness, numbness, or paralysis of the face, arm, or leg. These symptoms usually occur on one side of the body only
  • Dizziness or loss of balance or coordination

DIAGNOSIS


Rapid diagnosis is essential in successful treatment of stroke. A doctor will first look for symptoms. He or she will then look at the patient's medical history for the presence of risk factors in the patient's background and a description of when and how symptoms appeared.

If stroke is suspected, more sophisticated tools are used for diagnosis. Imaging techniques will show whether the stroke was caused by a blood clot or a hemorrhage. This information is needed to begin the correct type of treatment. Blood and urine tests are also carried out. Other tests used to determine if a stroke has occurred include an electrocardiogram, angiography, or ultrasound tests.

TREATMENT


Immediate Intervention

Stroke treatment usually occurs in two phases. The first phase involves immediate steps to save the patient's life. In many cases, this involves dissolving the blood clot. The most effective substance currently available for this step is tissue plasminogen activator, or tPA. In order to be effective, tPA must be given to the patient within three hours of the stroke. In such cases, tPA goes to the blood clot and begins dissolving it immediately. The normal flow of blood to the brain is restored.

Some patients can not be given tPA. For example, the doctor may not know exactly when the stroke occurred. In these cases, other blood-thinning agents can be used. The substance known as heparin is often used. Even ordinary aspirin can be effective in dissolving the blood clot.

RISK FACTORS FOR STROKE

The factors that determine a person's risk of having a stroke include age, sex, heredity, lifestyle choices, and other medical problems:

  • Age and sex. The risk of stroke increases with increasing age. Men are more likely to have a stroke than women.
  • Heredity. Blacks, Asians, and Hispanics all have higher rates of stroke than do whites. People with a family history of stroke are also at greater risk.
  • Lifestyle choices. Lifestyle choices that increase a person's risk for stroke include smoking, low level of physical activity, excessive alcohol consumption, or use of cocaine or other illegal drugs.
  • Other medical problems. Stroke risk is higher for people with diabetes, heart disease, high blood pressure, previous stroke, obesity, high cholesterol level, or high red blood count.

The primary goal in treating brain hemorrhages is to relieve pressure on the brain. Certain drugs can be used for this purpose. They include urea, mannitol, and the corticosteroids.

In some cases, surgery can be used to treat brain hemorrhages. A surgeon can close off blood vessels that have ruptured (broken open) in order to stop bleeding and help reduce pressure on the brain.

Rehabilitation

Once a patient's condition has been stabilized, rehabilitation can begin. Rehabilitation refers to a variety of methods for helping a patient recover normal functions to the extent possible. The patient may also need to learn how to use existing functions to take the place of those lost by the stroke.

About 10 percent of all patients who survive a stroke recover completely. Another 10 percent suffer severe disability and require institutional care for the rest of their lives. The remaining 80 percent of stroke survivors are able

to return to their homes and their daily routines. However, they may require additional therapy and support services.

PREVENTITIVE REHABILITATION. A program of rehabilitation consists of two parts. The first objective is to prevent medical complications of stroke. People who have had a stroke are at high risk for other serious medical problems including a second stroke.

Another possible complication is deep venous thrombosis (a blood clot in a vein). This condition may develop when a limb has become paralyzed and blood is no longer flowing normally in the limb. In such cases, the chance that a blood clot will develop greatly increases. If a blood clot forms and then breaks loose, it may travel to the lungs. In the lungs, it may cause a pulmonary embolism, (a blot clot in the lungs) that can very quickly lead to death.

Stroke patients may be kept on a special program of medication to prevent this complication. The program includes the use of drugs that thin blood out and reduce the chance that blood clots will form.

Another complication of stroke is caused by damage to throat muscles. A stroke patient may find it difficult to swallow normally. Food may get into the lungs, causing pneumonia or other infections. This condition can be treated with breathing exercises and temporary use of soft foods in the diet.

Depression is another side effect of stroke. Depression can be treated with drugs and with counseling that helps patients cope with the conditions caused by the stroke.

REHABILITATIVE THERAPY. Brain cells killed by stroke do not grow back. The functions those cells control may be seriously damaged or lost. For example, cells in one part of the brain control the ability to speak. If those cells are killed, the patient may lose the ability to speak.

Fortunately, surviving brain cells can sometimes be trained to take on new functions and patients may recover some or all of the function lost during the stroke. For instance, areas of the brain that were not previously responsible for a patient's ability to speak may learn how to control speech.

Rehabilitative therapy draws primarily on four types of treatment:

  • Physical therapy is used to help patients recover as much of their original body functions as possible. Treatment may involve exercises that help patients regain strength and become better able to move around. A physical therapist can provide advice on aids such as wheelchairs, braces, and canes.
  • Occupational therapy helps patients improve self-care skills, such as feeding, bathing, and dressing. The occupational therapist may also help the patient redesign his or her living area or work area to make movement easier. A specialist in speech and language may also be needed to help patients relearn the ability to speak and swallow correctly.
  • Mental health professionals treat mental problems, such as depression and loss of memory and thinking skills. They may also provide counseling to help patients deal with the new physical conditions resulting from stroke. Social workers and home caregivers may be needed to help patients adapt to the new challenges of dealing with tasks of everyday lives.
  • Support groups can provide an important source of information, advice, and comfort for stroke patients and their families. A support group consists of other individuals who have the same medical problem as the patient.

PROGNOSIS


Prognosis depends on both sex and ethnicity. The highest rate of fatalities occurs in black males (52 percent) and the lowest in white females (23 percent). People who survive stroke may experience a wide variety of disabilities.

PREVENTION


Stroke prevention involves two separate issues. One issue is keeping the patient alive after a stroke. If a stroke patient is treated quickly, chances of survival are much greater. Everyone should become familiar with the symptoms of stroke. When those symptoms appear, a person should seek medical advice as quickly as possible. In many cases, local 911 services may need to be called immediately.

A second issue in prevention is reducing one's risk for the condition. Some steps that one can take to this end include:

  • Stop smoking.
  • Bring blood pressure under control.
  • Get regular exercise.
  • Keep body weight down.
  • Avoid excessive alcohol consumption.
  • Get regular medical checkups and follow the doctor's advice regarding diet and medicines.

FOR MORE INFORMATION


Books

Caplan, L.R., M.L. Dyken, and J.D. Easton. American Heart Association Family Guide to Stroke Treatment, Recovery, and Prevention. New York: Times Books, 1996.

Warlow, C. P., et al. Stroke: A Practical Guide to Management. Boston: Blackwell Science, 1996.

Weiner, F.M., H.M. Lee, and H. Bell. Recovering at Home After a Stroke: A Practical Guide for You and Your Family. Los Angeles: The Body Press/Perigee Books, 1994.

Organizations

National Stroke Association. 96 Inverness Drive East, Suite I, Englewood, CO 801125112. (303) 6499299. http://www.stroke.org.

American Heart Association. 7272 Greenville Ave., Dallas, TX 752314596. (800) AHAUSA1 (2428721). http://www.amhrt.org.

Web sites

"Ask NOAH About: Heart Disease and Stroke." NOAH: New York Online Access to Health. [Online] http://www.noah.cuny.edu/heart_disease/heartdisease.html#S (accessed on October 31, 1999).

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stroke

stroke (apoplexy) (strohk) n. a sudden attack of weakness affecting one side of the body, resulting from an interruption to the flow of blood to the brain. The flow of blood may be prevented by thrombosis or embolism (ischaemic s.) or by haemorrhage (haemorrhagic s.). Prolonged reduction of blood pressure may result in more diffuse brain damage, as after a cardiorespiratory arrest. A stroke can vary in severity from a passing weakness or tingling in a limb (see transient ischaemic attack) to a profound paralysis, coma, and death. See also cerebral haemorrhage.

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"stroke." A Dictionary of Nursing. 2008. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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stroke

stroke (apoplexy) Interruption of the flow of blood to the brain. It is caused by blockage or rupture of an artery and may produce a range of effects from mild impairment to death. Conditions that predispose to stroke include atherosclerosis and hypertension. Many major strokes are prevented by treatment of risk factors, including surgery and the use of anticoagulant drugs. Transient ischaemic attacks (TIAs), or ‘mini-strokes’, which last less than 24 hours, are investigated to try to prevent the occurrence of a more damaging stroke.

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"stroke." World Encyclopedia. 2005. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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Stroke

Stroke

Carmen Visits Her Grandparents

What Is a Stroke?

Ischemic Strokes

Hemorrhagic Strokes

How Do People Know They Are Having a Stroke?

How Is Stroke Diagnosed?

How Is Stroke Treated?

Preventing Stroke

Resources

A stroke is the sudden destruction of brain cells when blood flow to the brain is disrupted, usually by a blockage in a blood vessel. It can cause weakness, speech problems, paralysis, and death, although most people survive.

KEYWORDS

for searching the Internet and other reference sources

Circulatory system

Ischemia

Stenosis

Thrombosis

Tissue plasminogen activator (t-PA)

Carmen Visits Her Grandparents

While eating lunch with her grandfather on a sunny afternoon, fourteen-year-old Carmen was in the midst of describing her summer camp plans when suddenly one side of her grandfathers face went slack. He tried to speak, but he was slurring his words. Without warning, he clutched the picnic table, and the drinking glass he held smashed to the ground.

Grandma! Carmen called. As her grandmother rushed to dial for emergency aid, Carmen held her grandfathers trembling hand.

In a few minutes, the ambulance arrived to carry him to the hospital, where the doctors quickly ordered a brain scan. The brain scan showed that Carmens grandfather had undergone an ischemic (is-KEE-mik) stroke. The doctors gave him t-PA, a powerful drug that dissolved a blood clot that was blocking the flow of blood to the brain. In a few days, he was ready to return home. Over several months, with the help of physical, occupational, and speech therapies, Carmens grandfather was able to make a full recovery.

What Is a Stroke?

A stroke occurs when the blood supply to part of the brain is suddenly interrupted, or when a blood vessel in the brain bursts, spilling blood into the spaces surrounding neurons (nerve cells). Like other cells, brain cells die when they no longer receive oxygen and nutrients from the bloodstream, or when they are damaged by sudden bleeding into or around the brain.

There are two major types of strokes: ischemic strokes involve a reduced blood flow to the brain. Hemorrhagic (hem-o-RAJ-ik) strokes involve bleeding in the brain. Ischemia (is-KEY-me-a) is the term used to describe the loss of oxygen and nutrients when there is inadequate blood flow. If ischemia is left untreated, it can lead to infarction (in-FARK-shun), or cell death and tissue death in the surrounding area.

Ischemic Strokes

Ischemic strokes occur when a blood vessel to the brain becomes blocked, suddenly decreasing or stopping blood flow and ultimately causing an infarction. Ischemic strokes account for approximately 80 percent of all strokes. A blood clot (also called a thrombus) is the most common cause of vessel blockage and brain infarction.

Blood clots

Blood clotting is necessary in the body to stop bleeding and to allow repair of damaged areas, but when blood clots develop in the wrong place within an artery, they can cause injury by stopping the normal flow of blood. Problems with clots develop more frequently as people age.

The U.S. and the World

Stroke is the third leading cause of death in the United States, killing more than 150,000 people each year.

According to the U.S. Centers for Disease Control and Prevention (CDC), the overall stroke death rate in the U.S. has been declining since 1950.

The American Heart Association reports that, on average, someone in the U.S. has a stroke every 53 seconds. About 600,000 strokes occur each year, including 100,000 strokes in people who have had at least one previous stroke.

About 4.4 million people in the U.S. have experienced a stroke and survived.

Stroke occurs about 20 percent more often in men than in women. But if a woman has a stroke, her chance of dying is about 20 percent higher than a mans chance.

The World Health Organization (WHO) estimates that strokes killed approximately 5.1 million people worldwide in 1998.

WHO reports that strokes are increasing worldwide and estimates that stroke and related heart disease could rival infectious disease as the leading cause of death in the developing world by 2020. Reasons cited for the increase include the rise of cigarette smoking as well as changes in diet and lifestyle.

An embolus is a clot that has formed in a blood vessel somewhere in the body, often in the heart. It can break away from the wall of the vessel where it was formed, travel through the circulatory system, and become wedged in the brain, causing an embolic stroke. Ischemic strokes also can be caused by the formation of a blood clot in one of the cerebral arteries (arteries supplying blood to the brain). If the clot grows large enough it will block blood flow.

Stenosis

Stenosis, or a narrowing of the arteries, also can cause ischemia. Stenosis can occur in large arteries or small arteries, and is called blood vessel disease or small vessel disease. The most common blood vessel disease that causes stenosis is atherosclerosis. Deposits of plaque (a mixture of cholesterol and other fatty substances) build up along the inner walls of larger and medium sized arteries causing thickening, hardening, and loss of elasticity of the artery walls.

Transient ischemic attacks (TIAs)

Some people get a warning that they may be headed for a future stroke. A transient ischemic attack (TIA) is a very small stroke caused by a temporarily blocked blood vessel. Unlike a full stroke, a TIA leaves no permanent damage. Symptoms are similar to those of a full stroke, but they usually last 24 hours or less. It is impossible to know whether the symptoms are caused by a stroke or by a TIA, so any symptoms should receive immediate medical attention. Having a TIA increases the risk of having a full stroke in the future, and medical attention can sometimes prevent or lessen the severity of the stroke.

Hemorrhagic Strokes

Hemorrhagic strokes are caused by burst blood vessels. In a healthy brain, the neurons do not come into direct contact with blood. Oxygen and nutrients move across a membrane from the blood vessel to the brain cells. Neuroglial (noo-ro-GLEE-al) cells help control which fluids and nutrients reach the neurons of the brain. When an artery in the brain bursts, blood spills out into the surrounding tissue, overriding the control of neuroglial cells and disrupting the delicate chemical balance of the brain.

Hemorrhagic strokes may occur in several ways. Aneurysms, or weak spots on artery walls, can stretch or balloon until eventually they break and spill blood into surrounding brain cells. Hemorrhages also can happen when plaque-encrusted arteries lose their elasticity and become brittle and thin enough to crack. Hypertension (high blood pressure) increases the risk that a brittle artery wall will give way and release blood into surrounding brain tissue.

A person who has an arteriovenous (ar-ter-ee-o-VEN-us) malformation (a tangle of defective blood vessels and capillaries within the brain that can rupture) also can be at increased risk for hemorrhagic stroke.

Although hemorrhagic strokes are less common than ischemic strokes, they have a much higher fatality rate, because more brain tissue can be damaged more quickly.

How Do People Know They Are Having a Stroke?

Symptoms of stroke, such as those experienced by Carmens grandfather, appear suddenly. They may include:

  • Numbness or weakness of the face, arm, or leg, particularly on one side.
  • Confusion, trouble talking, and trouble understanding speech.
  • H Difficulty seeing in one or both eyes.
  • Dizziness, difficulty walking, loss of balance, or loss of coordination.
  • Severe headache with no known cause.

Strokes are medical emergencies and require immediate medical attention.

How Is Stroke Diagnosed?

Doctors have diagnostic techniques and imaging tools to help diagnose strokes quickly and accurately. When a person with signs and symptoms of stroke arrives at the hospital, the first diagnostic step is a physical examination and a medical history. Often, an electrocardiogram and a CT scan* will be done to check for signs of heart disease, evidence of prior TIAs, and heart rhythm disturbances. The patient may be asked to answer questions and to perform several physical and mental tests to evaluate the possibility or severity of brain damage.

* CT scans
(CAT scans) are computerized axial tomography (to-MOG-ra-fee), which uses x-rays and computers to view structures inside the body.

Imaging tests also help health care professionals to evaluate stroke. The CT scan may rule out a hemorrhage or may show evidence of early infarction. If the stroke is caused by a hemorrhage, a CT scan can reveal any bleeding into the brain. MRI scans* may be taken to detect subtler changes in brain tissue or areas of dead tissue soon after a stroke.

* MRI
which is short for magnetic resonance imaging, produces computerized images of internal body tissues based on the magnetic properties of atoms within the body.

How Is Stroke Treated?

Stroke treatment often involves medication, surgery, and rehabilitation. Acute stroke therapy uses medication to stop a stroke while it is happening by quickly dissolving the blood clot that is causing the stroke or by stopping the bleeding of a hemorrhagic stroke.

Medication and surgery

Physicians have a number of different medications that can be used to treat stroke:

  • Antithrombotics work to counteract the chemicals in the body that cause blood to clot.
  • Antiplatelet drugs prevent clotting by decreasing the activity of cells that contribute to the clotting properties of blood. They can reduce the risk of ischemic stroke.
  • Anticoagulants reduce the stroke risk by thinning the blood and reducing its clotting properties.
  • Thrombolytic agents are used to treat an ongoing stroke. These drugs stop the stroke by dissolving the blood clot that is blocking the blood vessel supplying the brain. Tissue plasminogen activator (t-PA) can be effective if given intravenously within 3 hours of the onset of stroke symptoms when a CT scan confirms that a person has suffered an ischemic stroke.

Surgery may be used to prevent stroke, to treat acute stroke, or to repair vascular malformations in and around the brain.

Rehabilitation

Post-stroke rehabilitation helps people overcome the disabilities that result from stroke damage. For some people, like Carmens grandfather, acute stroke treatment and post-stroke therapy led to a full recovery. For others, recovery is only partial.

Although strokes occur in the brain, they may affect the entire body and all activities of daily living. Some of the disabilities that may result from a stroke include paralysis, or partial paralysis, of many different parts of the body, difficulties with memory and concentration, speech problems, and emotional distress as people cope with their changed circumstances. Rehabilitation may involve several different forms of therapy:

  • Physical therapy helps people to regain movement, balance, and coordination and to reestablish skills such as sitting, walking, and moving from one activity to another.
  • Occupational therapy helps people who have had strokes readapt to everyday life by relearning practical skills needed at home, such as dressing, eating, bathing, reading, and writing.
  • Speech therapy addresses the speech and language problems that arise when a stroke causes brain damage in the language parts of the brain. Speech therapy helps people who have no deficits in cognition or thinking but have problems understanding written words, or problems forming speech. One common problem for people who have suffered stroke is aphasia (a-FAY-zha), a condition in which comprehension or expression of words is impaired. Speech therapists help stroke patients by working to improve language skills, develop alternative ways of communicating, and develop coping skills to deal with the frustration of not being able to communicate easily.
  • Psychotherapy often is useful following a stroke, because depression, anxiety, frustration, and anger are common post-stroke symptoms.

Preventing Stroke

The most important risk factors* for stroke are hypertension (high blood pressure), heart disease, diabetes, and smoking. Others things that increase the risk of having a stroke include heavy alcohol consumption, high cholesterol levels, and genetic or congenital conditions, such as vascular (blood vessel) abnormalities.

* risk factors
are any factors that make it likelier a person will get a certain disease.

Hypertension People with hypertension or high blood pressure have a risk for stroke that is four to six times greater than those without hypertension. One third of adults in the United States have high blood pressure. Antihypertensive drugs and attention to diet can decrease a persons risk for stroke.

Heart disease

After hypertension, the second most powerful risk factor for stroke is heart disease, particularly the condition known as atrial fibrillation*. This condition is more prevalent in older people. Other forms of heart disease that can increase the chances of having stroke include malformations of heart muscle and some heart valve diseases. Cardiac surgery to correct heart malformation or the effects of heart disease also can cause stroke. Strokes occurring during surgery often are the result of dislodged plaques.

* atrial fibrillation
(AY-tree-al fib-ri-LAY-shun) is the arrhythmic or irregular beating of the left upper chamber of the heart. This leads to an irregular flow of blood and to the formation of blood clots that can leave the heart and travel to the brain, causing a stroke.

Ike

Dwight D. Eisenhower (1890-1969) was a U.S. Army general and the thirty-fourth president of the United States. Ike, as he was known, had a meteoric rise as a military commander during World War II. In 1953, he was elected to his first term in the White House. Despite having a stroke and a heart attack, he was elected to a second term. Eisenhower completed his presidency in 1961, when John F. Kennedy was sworn in as thirty-fifth president.

Diabetes

People with diabetes have three times the risk of stroke as those without diabetes. The relative risk is highest in the fifth and sixth decades of life and decreases after that. People with diabetes who control their blood sugar level well, who avoid smoking, and who avoid or control hypertension, are less likely to have strokes.

Cigarette smoking

Smokers have a 40 to 60 percent greater chance of having a stroke than nonsmokers. Smoking increases a persons chance for ischemic stroke, independent of all other risk factors.

Blood Cholesterol levels

High cholesterol levels can contribute to the risk of stroke. Too much cholesterol in the blood is associated with plaque developing in the walls of arteries (atherosclerosis), leading to stenosis of blood vessels. By lowering cholesterol through diet and exercise, a person can lower the risk for atherosclerosis and stroke. Doctors may prescribe cholesterol-lowering medication for people with high cholesterol levels.

Lifestyle Changes Many strokes can be prevented with changes in lifestyle. These changes include:

  • Stopping smoking.
  • Avoiding binge drinking and overconsumption of alcohol.
  • Avoiding illicit drugs: cocaine and crack cocaine can cause stroke, and marijuana may damage blood vessels, which can cause stroke.

Medical measures To prevent stroke, doctors may prescribe medications to lower blood pressure and cholesterol levels. In some cases, particularly if a person has atrial fibrillation, doctors may prescribe regular doses of aspirin, coumadin, or other medications that prevent blood clotting. If carotid (ka-ROT-id) arteries (arteries supplying the brain) are partially blocked by plaque, surgery can clear them and prevent strokes in many cases.

Strokes can happen to people of either sex no matter what their age or racial background. Transient ischemic attacks (TIAs) multiply a persons risk of having a full stroke and should receive immediate medical attention.

See also

Aneurysm

Diabetes

Dysrhythmia

Heart Disease

Hypertension

Paralysis

Speech Disorders

Substance Abuse

Thrombosis

Resources

U.S. National Institute of Neurological Disorders and Stroke (NINDS), Building 31, Room 8A16, 31 Center Drive, MSC 2540, Bethesda, MD 20892-2540. The NINDS website posts many useful fact sheets about stroke, with information on stroke prevention, treatment, research, and clinical trials. Telephone 800-352-9424 http://www.ninds.nih.gov/patients/Disorder/STROKE/strokehp.htm

National Stroke Association, 96 Inverness Drive East, Suite 1, Englewood, CO 80112-5112. Telephone 800-787-6537 http://www.stroke.org

American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231. http://www.amhrt.org

World Health Organization (WHO), Avenue Appia 20, 1211 Geneva 27, Switzerland. WHOs website posts information about stroke and other non-communicable diseases worldwide. http://www.who.org/home/map_ht.html

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stroke

stroke Also known as cerebrovascular accident (CVA); damage to brain tissue by hypoxia due to blockage of a blood vessel as a result of thrombosis, atherosclerosis, or haemorrhage. The severity and nature of the effects of the stroke depend on the region of the brain affected and the extent of damage. Hypertension and hypercholesterolaemia are major risk factors.

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DAVID A. BENDER. "stroke." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

DAVID A. BENDER. "stroke." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1O39-stroke.html

DAVID A. BENDER. "stroke." A Dictionary of Food and Nutrition. 2005. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-stroke.html

stroke

stroke2 act of striking XIII; striking of a clock XV; linear mark XVI; (earlier s. of God's hands XVI) seizure by disease XVII. ME. strōk :-OE. *strāc :- Gmc. *straikaz, f. *straik- *strī́k- STRIKE.

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T. F. HOAD. "stroke." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

T. F. HOAD. "stroke." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (June 27, 2016). http://www.encyclopedia.com/doc/1O27-stroke1.html

T. F. HOAD. "stroke." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved June 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-stroke1.html

stroke

stroke1 rub softly with the hand or an implement. OE. strācian = MLG., MDu. strēken (Du. streeken), OHG. streihhōn (G. streichen), f. Gmc. *straik- *strī́k- STRIKE.

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stroke

stroke A type of input to a graphics system consisting of a sequence of positions, possibly with other information. See also logical input device.

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JOHN DAINTITH. "stroke." A Dictionary of Computing. 2004. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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stroke

strokeawoke, bespoke, bloke, broke, choke, cloak, Coke, convoke, croak, evoke, folk, invoke, joke, Koch, moke, oak, okey-doke, poke, provoke, revoke, roque, smoke, soak, soke, spoke, stoke, stony-broke (US stone-broke), stroke, toke, toque, woke, yoke, yolk •Holyoake • artichoke • gentlefolk •menfolk • kinsfolk • womenfolk •townsfolk • fisherfolk • holmoak •woodsmoke • cowpoke • slowpoke •backstroke • breaststroke • keystroke •heatstroke • sidestroke • downstroke •sunstroke • upstroke • masterstroke •counterstroke • equivoque

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"stroke." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 27 Jun. 2016 <http://www.encyclopedia.com>.

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