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Dizziness

Dizziness

Definition

Dizziness is a general term that describes sensations of imbalance and unsteadiness, such as vertigo, mild turning, imbalance, and near fainting or fainting. Feelings of dizziness stem from the vestibular system, which includes the brain and the parts of the inner ear that sense position and motion, coupled with sensory information from the eyes, skin, and muscle tension.

Description

Because dizziness is a general term for a variety of feelings of instability, it spans a large range of symptoms. These symptoms range from the most dramatic, vertigo, to the least severe, imbalance. Included in these feelings is fainting, which results in a loss of consciousness.

Vertigo is an acute feeling of violent rotation. People with vertigo often feel as if they are tilting or falling through space. Vertigo is most often caused by problems with the vestibular system of the inner ear. Symptoms can be brief, or may last for extended periods of time and may be accompanied by changes in pulse and blood pressure, perspiration, nausea, and a type of rapid eye movement called nystagmus.

Mild turning is a less violent type of vertigo. People with mild turning are still able to function in normal daily routines. However, a feeling of turning may continue for weeks. Mild turning is usually a symptom of inner ear dysfunction. It may also result from transient ischemic attack , or a lack of blood flow to the brain. People who have suffered from strokes may feel mild turning for periods of time. Mild turning may also be associated with multiple sclerosis , AIDS , or head trauma.

Imbalance is a feeling of instability or floating. It is associated with many general medical problems such as the flu or infection. Imbalance can also be associated with arthritis, especially in the neck, or another neurological problem.

Fainting is a sudden loss of consciousness and near fainting is a feeling of extreme light-headedness with a sinking or falling feeling. Vision usually becomes hazy or dimmed and the extremities become weak. Both fainting and near fainting are caused by lack of blood flow to the brain. Anything that causes a rapid drop in blood pressure, such as a heart attack or an insulin reaction in a diabetic, can result in fainting or near fainting. Panic attacks that cause a person to exhale a lot of carbon dioxide can cause fainting or near fainting.

Vestibular system

The vestibular system is the sensory system located in the inner ear that helps the body to maintain balance. Balance in the human body is coordinated by the brainstem, which, with speed and precision, collects information from other parts of the brain and sensory organs throughout the body. It is the brainstem that sends neurological instructions to the muscles and joints. The sensory organs that play critical roles relaying information to the brain-stem include the skin, eyes, muscles and joints, and the vestibular system in the inner ear. Dizziness may result with dysfunction in any of these components or in the nerves that connect them.

Brain

The cerebellum , which is responsible for coordination and the cerebral cortex, provides neurological information to the brainstem. For example, the cerebellum is the organ that informs the body how to shift weight when going down a flight of stairs and how to balance on a bicycle. These processes are accomplished without conscious thinking.

In order to maintain balance, the brainstem depends on input from sensory organs including the eyes, muscles, joints, skin and ears. This information is relayed to the brainstem via the spinal cord. The combined neurological receptor system, which involves the brainstem, spinal cord, and sensory organs, is called the proprioceptive system. Proprioceptive dysfunction may result in dizziness, and people with problems with their proprioceptive system may fall often. Additionally, as people age, problems with proprioception become more common.

Sensory organs

Visual information is of particular importance to maintaining balance. The visual systems most involved are the optokinetic and pursuit systems. The optokinetic system is the motor impulse responsible for moving the eyes when the head moves, so that the field of vision remains clear. The pursuit system allows a person to focus on a moving object while the head remains stationary. Both of these systems feed information about the person's position relative to the surroundings to the brainstem. A specific type of eye movement called nystagmus, which is repetitive jerky movements of the eye, most often in the horizontal direction, may cause dizziness. Nystagmus may indicate that neurologic signals from the optokinetic or pursuit systems are not in agreement with the other balance information received by the brain.

Sensory information from muscles, joints, and skin plays a key role in balance. The muscles and joints of the human body are lined with sensory receptors that send neurological information about the position of the body to the brainstem. For example, receptors in the neck muscles tell the brain which way the head is turned. The skin, in particular the skin of the feet and buttocks, is covered with pressure sensors that relay information to the brain regarding what part of the body is touching the ground.

Peripheral vestibular system

The ear, particularly the inner ear, plays a critical role in maintaining balance. The inner ear contains two major parts: the cochlea, which is mostly used for hearing, and the vestibular apparatus, also known as the peripheral vestibular system, which is important in balance. A set of channels connects the two parts of the ear and therefore any disease that affects hearing may also affect balance, and vice versa.

The peripheral vestibular system consists of a series of canals and chambers, all of which are made of membranes. This membrane system is filled with a fluid called endolymph. The peripheral vestibular system is further embedded in the temporal bone of the skull. In the space between the temporal bone and the membranes of the peripheral vestibular system resides a second fluid called perilymph. Endolymph and perilymph each have a different chemical makeup consisting of varying concentrations of water, potassium, sodium, and other salts. Endolymph flows out of the peripheral vestiubular system into an endolymphatic sac and then diffuses through a membrane into the cerebrospinal fluid that bathes the brain. Peri-lymph flows out of the peripheral vestibular system and directly into the cerebrospinal fluid. When the flow pressures or chemical compositions of the endolymph and perilymph change, feelings of dizziness can occur. These types of changes may be related to Mèniére's disease.

The vestibular apparatus is made up of two types of sensory organs: otolith organs and semicircular canals. The otolith organs sense the direction of gravity, while the semi-circular canals sense rotation and movement of the head.

Two otolith organs in each ear are called the saccule and the utricle. The saccule is oriented in a vertical direction when a person is standing and, best senses vertical motion of the head. The utricle is nearly horizontal when a person is standing, so it best senses horizontal motion of the head. Each organ consists of calcium carbonate crystals embedded in a gel. Special hair-producing cells extend into the gel from below. As the head moves, gravity and inertia cause the crystals to bend the hairs, which are in contact with nerves. Information on the position and motion of the head is thus relayed to the brain. If the hairs or the crystals in the otolith organs are damaged, feelings of dizziness may result.

In each ear, there are also three semicircular canals that lie on planes that are perpendicular to each other. The canals are connected together by a main chamber called a vestibule. The canals and the vestibule are filled with endolymph fluid. Near its connection to the vestibule, one end of each of the canals widens into a region called the ampulla. One side of the ampulla is lined with specialized sensory cells. These cells have hairlike structures that extend into a gelatinous structure called a cupula. As the head moves in a given plane, the endolymph inside the semicircular canal in that plane remains stationary due to inertia. The cupula, however, moves because it is attached to the head. This puts pressure on the cupula, which in turn moves the hairlike structures. The bending of the hairlike structures stimulates nerves, alerting the brain that the head is moving in a particular plane. By integrating information from all three planes in which the semicircular canals lie, the brain reconstructs the three-dimensional movement of the head. If information from one of the semicircular canals does not agree with that of another, or if the information generated by semicircular canals in one ear does not agree with the information produced by the other ear, feelings of dizziness may result.

All of the signals from the peripheral vestibular system travel to the brain along the eighth cranial nerve, also called the vestibular nerve. Damage to this nerve, either through head trauma or the growth of tumors, can also cause feelings of dizziness. Neurological information from the semicircular canals seems be more important to the brain than information from the otolith structures. If the eighth cranial nerve on one side of the head is damaged, but the other side remains intact, the brain learns to compensate over time; however, the mechanics involved in this process are not well understood.

Demographics

Dizziness is an extremely common symptom occurring in people of all ages, ethnicities, and socioeconomic backgrounds. Balance disorders increase with age, and by age 75, dizziness is one of the most common reasons for visiting a doctor. In the general population, dizziness is the third most common reason that patients visit doctors. According to the National Institutes of Health (NIH), about 42% of the population of the United States will complain of dizziness at some point in their lives. In the United States, the cost of medical care for patients with symptoms of imbalance is estimated to be more than $1 billion per year.

Diseases associated with dizziness

Because it involves so many different parts of the body, the balance system may exhibit signs of dysfunction for a variety of reasons. Dizziness may be caused by problems with the central nervous system , the vestibular system, the sensory organs, including the eyes, muscles and joints, or more systemic disorders such as cardiovascular disease, bacterial and viral diseases, arthritis, blood disorders, medications, or psychological illnesses.

Central nervous system dysfunction

Any problem that affects the nerves leading to the brain from vestibular or sensory organs, the spinal cord, the cerebellum, the cerebral cortex, or the brainstem may result in dizziness. In particular, tumors that affect any of these organs are of concern. In addition, disorders that affect blood supply to the central nervous system, such as transient ischemic attacks, stroke , migraines, epilepsy , or multiple sclerosis, may result in feelings of dizziness.

BRAINTUMORS Although rare, acoustic neuroma is a benign tumor growing on the vestibulo-cochlear nerves, which reach from the inner ear to the brain. It may press as well on blood vessels that flow between the peripheral vestibular system and the brain. Symptoms included ringing in one ear, imbalance, and hearing loss. Distortion of words often becomes increased as the tumor grows and disturbs the nerve. Treatment requires surgical removal of the tumor, which nearly always returns the sense of balance to normal, although some residual hearing loss may occur.

Other brain tumors may also cause feelings of dizziness. These include tumors that originate in the brain tissue, such as meningiomas (benign tumors) and gliomas (malignant tumors). Sometimes tumors from other parts of the body may metastasize in the brain and cause problems with balance.

CEREBRAL ATROPHY Age causes atrophy (deterioration) of brain cells that may result in slight feelings of imbalance. More severe forms of dizziness may result from other neurological disorders.

BLOOD SUPPLY DISORDERS If the blood flow and oxygenation to the cerebellum, cerebral cortex, or brain-stem is not adequate, feelings of dizziness can result. Such symptoms can result from several types of disorders, including anemia, transient ischemic attacks (TIAs), and stroke.

TIAs are temporary loss of blood supply to the brain, often caused by arteriosclerosis (hardening of the arteries). In addition to a brief period of dizziness or vertigo, symptoms include a transient episode of numbness on one side of the body, and slurred speech and/or lack of coordination. If the loss of blood supply to the brain is due to a blockage in one of the arteries in the neck, surgery may correct the problem.

Strokes, or cerebrovascular accidents (CVA), occur in three major ways. A thrombotic stroke occurs when a fatty deposit forms a clot in an artery, blocking blood supply to the brain. An embolic stroke occurs when part of a clot from another part of the body breaks off and obstructs an artery leading to the brain. A hemorrhagic stroke occurs when blood vessels in the brain hemorrhage, leaving a blood clot in the brain.

PERIPHERAL VESTIBULAR SYSTEM DYSFUNCTION When balance problems are brief or intermittent, the peripheral vestibular system is usually the cause. Many different problems may be at the root of vestibular disorder.

BENIGN PAROXYSMAL POSITIONAL VERTIGO (BPPV) Benign paroxysmal positional vertigo occurs following an abrupt change in position of the head. Often, onset of vertigo occurs when patients roll from their back onto the side, and it usually subsides in less than a minute. BPPV can result from head trauma, degeneration of the peripheral vestibular system with age, infection of the respiratory tract, high blood pressure, or other cardiovascular diseases. Those who suffer from an infection of their vestibular system, causing severe vertigo that lasts up to several days, can develop BPPV any time within the next eight years. BPPV is also associated with migraine headaches .

Two theories on the cause of BPPV currently exist. One suggests that BPPV will occur when the calcium carbonate crystals in the otolith organs (the saccule and the utiricle) are displaced and become lodged in the cupula of the semicircular canals due to head trauma, infection, or degeneration of the inner ear canals. This displacement will stimulate the nerves from the semicircular canals when the head rotates in a particular position, indicating to the brain that the person is spinning. However, the rest of the sensory organs in the body report that the body is stationary. This conflicting information produces vertigo. The calcium carbonate crystals dissolve after a brief time, and the symptom is rectified. The second theory suggests that cellular debris accumulates into a mass that moves around the semicircular canals, exerting pressure on the cupula and causing vertigo. When the mass dissolves, the symptoms subside.

INNER EAR INFECTIONS Inner ear infection, or vestibular neuronitis, occurs some time after a person has suffered from a viral infection. Onset includes a violent attack of vertigo, including nausea, vomiting, and the inability to stand or walk. Symptoms subside in several days, although feelings of unsteadiness may continue for a week or more. A swelling of the vestibular nerve following a viral infection causes vestibular neuronitis.

Sometimes the inflammation can recur over several years. A viral infection affecting the inner ear, but not the vestibular nerve, is called viral labyrinthitis. Labyrinthitis can cause hearing loss, but all other symptoms are similar to vestibular neuronitis.

Severe bacterial infections can also cause inflammation of the inner ear. These cases include risk of deafness, inflammation of the brain, and meningitis (inflammation of the membranes surrounding the brain and spinal cord). Otitis occurs when fluid accumulates in the middle ear, causing feelings of imbalance, mild turning, or vertigo. When the infection reaches the inner ear, the disease is called acute suppurative labyrinthitis. Treatment for any bacterial infection in the ear is critical to prevent long-term damage to hearing and balance organs.

PERILYMPH FISTULA Perilymph fistulas are openings that occur between the middle ear and the inner ear. This allows a hole through which perilymph can flow, changing the pressure of perilymph flowing into the brain and causing dizziness. Fistulas often form as a result of head trauma or abrupt changes in pressure. Symptoms may also include hearing loss, ringing in the ears, coordination problems, nystagmus, and headaches. Most fistulas heal with time; however, in severe cases, surgical procedures are used to close the hole, using a tissue graft.

MÈNIÉRE'S DISEASE In 1861, French physician Prosper Mèniére described Mèniére's disease as having four particular symptoms: vertigo lasting for an hour or more, but less than 24 hours; ringing or buzzing sounds in the ear; feeling of pressure or fullness in the ear; and some hearing loss. Some people are affected in both ears; others just one ear. Onset of Mèniére's may be related to stress, although not in all cases. Nystagmus is usually associated with the attacks.

Mèniére's disease is thought to be caused by an accumulation of endolymph within the canals of the inner ear, a condition called endolymphatic hydrops. This causes produces a swelling in the canals containing endolymph, which puts pressure on the parts of the canals containing perilymph. The result affects both hearing and balance. In severe cases, it is feared that the endolymphatic compartments may burst, disrupting both the chemical and pressure balances between the two fluids.

The cause of the accumulation of endolymph is unknown, although it can be related to trauma to the head, infection, degeneration of the inner ear, or some other regulatory mechanism. Syphilis is often associated with Mèniére's disease, as are allergies and leukemia. Some suggest that Mèniére's disease is an autoimmune dysfunction. There may be a genetic predisposition to Mèniére's disease.

Mèniére's disease is usually treated with meclizine (Antivert), antihistamines, and sedatives. Diuretics can be used to rid the body of excess endolymph. Salt-free diets can also help to prevent the accumulation of fluid in the ears.

Systemic disorders

Dizziness may be a symptom of a disorder that affects the whole body, or systems within the body. Dizziness may also be the result of systemic toxicity to substances such as medications and drugs.

POSTURAL HYPOTENSION The major symptom of postural hypotension, also called orthostasis, is low blood pressure. When a person stands up from a prone position, blood vessels in the legs and feet must constrict to force blood to the brain. When blood pressure is low, the blood vessels do not constrict quickly or with enough pressure and the result is a lag before blood reaches the brain, causing dizziness. Postural hypotension can be treated with an increase in fluid intake or with blood pressure medication.

HEART CONDITIONS A variety of heart conditions can cause feelings of dizziness. In particular, arrhythmia, a dysfunction of the heart characterized by an irregular heartbeat, decreases blood supply to the brain in such a way as to cause balance problems. In most cases, symptoms of dizziness associated with arrhythmia result from problems with heart valves, such as narrowing of the aorta and mitral valve prolapse.

INFECTIOUS DISEASES Influenza and flu-like diseases can cause dizziness, especially if accompanied by fever. The virus herpes zoster oticus causes painful blisters and shingles . If the virus attacks the facial nerve, it may result in vertigo. Several bacterial diseases can result in dizziness, including tuberculosis, syphilis, meningitis, or encephalitis. One of the major symptoms of Lyme disease , which is caused by infection of a microorganism resulting from a deer tick bite, is dizziness.

BLOOD DISORDERS A variety of diseases of the blood result in feelings of dizziness. These diseases include anemia, or a depletion of iron in the blood, sickle-cell anemia, leukemia, and polycythemia.

DRUGS AND OTHER SUBSTANCES A variety of substances ingested systemically to prevent disorders of diseases can result in feelings of dizziness. In particular, overdose of aspirin and other anti-inflammatory drugs can cause problems with balance. Antibiotics taken for extended periods of time are also known to cause dizziness. Streptomycin is known to damage the vestibular system, if taken in large doses. Medicines that are used to treat high blood pressure can lower blood pressure so much as to cause feelings of light-headedness. Quinine, which is taken to treat malaria, can cause dizziness, as can antihistamines used to prevent allergy attacks. Chemotherapy drugs are well known to have various side effects, including dizziness. Alcohol, caffeine, and nicotine are also known to cause dizziness, when taken in large doses.

Diagnosis

Because maintaining posture integrates so many different parts of the body, diagnosing the actual problem responsible for dizziness often requires a battery of tests. The cardiovascular system, the neurological system, and the vestibular system are all examined.

Blood pressure is one of the most important cardiovascular measurements made to determine the cause of imbalance. Usually the physician will measure blood pressure and heart rate with the patient lying down, and then again after the patient stands up. If blood pressure drops significantly and the heart rate increases more than five beats per minute, this signals the existence of postural hypotension. Dizziness in people suffering from diabetes or on blood pressure medicine may be caused by postural hypotension.

Neurological tests

Because the central nervous system is integral to maintaining balance, neurological tests are often performed on patients with symptoms of dizziness. A test of mental status is often performed to ascertain that mental function is healthy. Physicians may test tendon reflexes to determine the status of peripheral and motor nerves, as well as spinal cord function. Nerves in different parts of the body may also be evaluated. In addition, physicians may test muscle strength and tone, coordination, and gait.

Neurologists may also perform a variety of computerized scans that determine if tumors or acoustic neuromas are present. These tests include magnetic resonance imaging (MRI) , computerized tomography (CT ), and electroencephalogram (EEG).

Tests of the vestibular system

Most often performed by a otolaryngologist, the battery of tests performed to determine the health of the vestibular system include the Dix-Halpike test, electrostagmography, hearing tests, rotation tests, and posturography.

DIX-HALPIKE TEST The Dix-Halpike test, also called the Halpike test, is performed to determine if a patient suffers from benign paroxysmal positional vertigo (BPPV). The patient is seated and positioned so that his or her head hangs off the edge of the table when lying down. The patient's head is moved 45 degrees in one direction. The patient is then asked to lie down, without moving his or her head. The same procedure will be repeated on the other side. If feelings of vertigo result from this movement, BPPV is usually diagnosed.

ELECTRONYSTAGMOGRAPHY (ENG) Considered one of the most telling diagnostic tests to determine the cause of dizziness, electronystagmography consists of a series of evaluations that test the interactions between the vestibular organs and the eyes, also called the vestibulo-ocular reflex. Results from this test can inform the physician whether problems are caused by the vestibular system or by the central nervous system.

The most common diagnostic feature observed during ENG is nystagmus, an involuntary movement of the pupils that allows a person to maintain balance. In healthy persons, nystagmus consists of a slow movement in one direction in response to a change in the visual field and quick corrective movement in the other direction. In persons with disorders of the vestibular organs, nystagmus will produce quick movements in the horizontal direction. People with neurologic disorders will show signs of nystagmus in the vertical direction or even in a circular pattern.

In most of the ENG tests, electrodes taped to the patient's head record nystagmus as the patient is exposed to a variety of moving lights or patterns of stripes that stimulate the vestibular system. The patient may be asked to stand and lie in various positions for the tests. Also, included in the ENG is a caloric test in which warm water and cool water are circulated through the outer ear. This causes a slight expansion or contraction of the endolymph in the inner ear and simulates movement cues to the brain.

HEARING TESTS Because the cochlea and the vestibular organs are adjacent to one another, hearing dysfunction can often be related to problems with dizziness. Audiograms include tests for both hearing and interpreting sounds, and can determine whether or not problems exist in the middle ear, the inner ear, or the auditory nerve.

ROTATION TESTS Rotation tests evaluate the vestibulo-ocular reflex and provide important information when the dysfunction is common to both ears. Electrodes are usually taped to the face to monitor eye movement, and the patient is placed in a chair. The chair rotates at different speeds through different arcs of a circle. The audiologist may also ask the patient to focus on different objects as the chair is rotated.

POSTUROGRAPHY During posturography tests, a patient stands on a platform that measures how weight is distributed. During the test, the patient will close and open his or her eyes or look into a box with different visual stimuli. The platform is computer controlled so that it can gently tip forward or backward or from side to side. Posturography measures how much the patient sways or moves in response to the stimuli. This provides information on the function of the proprioceptive system, as well as the vestibular system.

Treatment

If symptoms of dizziness are found to be associated with systemic diseases such as diabetes, hypotension, or other infectious diseases, or with neurological disorders, treatment for the dizziness is usually successful.

In many patients, dizziness caused by vestibular dysfunction tends to dissipate with time and with little treatment. However, available and common treatments for vestibular problems include physical therapies, medications, and surgeries. In addition, low-salt diets, relaxation techniques, and psychological counseling may be used as treatment.

Exercises and therapy

The physical therapies to decrease dizziness fall into two major groups. Compensation therapies help train the patient's brain to rely on the sensory information it receives to maintain balance, and to ignore information from damaged organs. Exercises in a compensation program are designed to focus on the movements that cause dizziness so that the brain can adapt to these behaviors. In addition, exercises that teach the patient how to keep the eye movements separate from head movements and to practice balancing in various positions are used.

Specific exercises aimed at relieving benign paroxysmal positional vertigo (BPPV), called canalith repositioning procedures, have recently been developed. By turning the head to one side and moving from a sitting to lying position in a certain sequence, BPPV can be quickly relieved. The movements in the canalith repositioning procedures are intended to move calcium carbonate crystals from the semicircular canals back to the utricle. The success rate with these exercises can be up to 90%.

Medications

A variety of medications are used to treat vertigo. These include vestibular suppressants, which seem to work by decreasing the rate of firing of nerve cells. Common vestibular suppressants are meclizine (Antivert, Bonine, and Vetrol). Also prescribed are anti-nausea medications such as promethazane (Phenergan) and anti-histamines (Benadryl, Dramamine). For dizziness brought on by anxiety attacks, anti-anxiety drugs such as diazepam (Valium) and lorazepam (Ativan) may be used. These drugs all have side effects and are seldom prescribed for long periods of time.

Surgery

Surgery is usually the last step in the treatment of dizziness, only used after therapy and medications have failed. One of the more common surgical procedures for treating vestibular disorders is patching perilymph fistulas, or tears, at the tops of the semicircular canals. Surgery may also be used to drain excess fluid from the endolymphatic canals to relieve endolymphatic hydrops. Cutting the vestibular nerve just before it joins with the auditory nerve to form the eighth cranial nerve can also be performed to alleviate severe problems with dizziness. Finally, the entire labyrinth can be destroyed in a procedure called a labyrinthectomy, although this is usually only performed when hearing has been completely lost as well.

Resources

BOOKS

Blakely, Brian W., and Mary-Ellen Siegel. Feeling Dizzy: Understanding and Treating Dizziness, Vertigo, and Other Balance Disorders. New York: Macmillan USA, 1997.

Olsen, Wayne, ed. Mayo Clinic on Hearing: Strategies for Managing Hearing Loss, Dizziness, and Other Ear Problems. Rochester, MN: Mayo Clinic Health Information, 2003.

OTHER

"Vestibular Disorders: An Overview." The Vestibular Disorders Association. November 3, 2003. (April 4, 2004). <http://www.vestibular.org/overview.html>.

"Equilibrium Pathologies." Archives for Sensology and Neurootology in Science and Practice. January 2004 (April 4, 2004). <http://www.vertigo-dizziness.com/english/equilibrium_pathologies.html>.

"Dizziness." The Mayo Clinic. October 10, 2002 (April 4, 2004). <http://www.mayoclinic.com/invoke.cfm?id=DS00435>.

"Dizziness and Motion Sickness." The American Academy of Otolaryngology and Head and Neck Surgery. January 30, 2004 (April 4, 2004). <http://www.entnet.org/healthinfo/balance/dizziness.cfm>.

"Balance, Dizziness and You." National Institute on Deafness and other Communication Disorders. November 20, 2003 (April 4, 2004). <http://www.nidcd.nih.gov/health/balance/baldizz.asp>.

ORGANIZATIONS

Vestibular Disorders Association. P.O. Box 4467, Portland, OR 97208. (503) 229-7705 or (800) 837-8428. <http://www.vestibular.org>.

Juli M. Berwald, PhD

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Dizziness

Dizziness

Definition

As a disorder, dizziness is classified into three categories: vertigo, syncope, and nonsyncope nonvertigo. Each category has its own set of symptoms, all related to the sense of balance. In general, syncope is defined by a brief loss of consciousness (fainting) or by dimmed vision and feeling uncoordinated, confused, and lightheaded. Many people experience a sensation like syncope when they stand up too fast. Vertigo is the feeling that either the individual or the surroundings are spinning. This sensation is like being on a spinning amusement park ride. Individuals with nonsyncope nonvertigo dizziness feel as though they cannot keep their balance. This feeling may become worse with movement.

Description

The brain coordinates information from the eyes, the inner ear, and the body's senses to maintain balance. If any of these information sources is disrupted, the brain may not be able to compensate. For example, people sometimes experience motion sickness because the information from their body tells the brain that they are sitting still, but information from the eyes indicates that they are moving. The messages do not correspond and dizziness results.

Vision and the body's senses are the most important systems for maintaining balance, but problems in the inner ear are the most frequent cause of dizziness. The inner ear, also called the vestibular system, contains fluid that helps fine tune the information the brain receives from the eyes and the body. When fluid volume or pressure in one inner ear changes, information about balance is altered. The discrepancy gives conflicting messages to the brain about balance and induces dizziness.

Certain medical conditions can cause dizziness because they affect the systems that maintain balance. For example, the inner ear is very sensitive to changes in blood flow. Because medical conditions such as high blood pressure or low blood sugar can affect blood flow, these conditions are frequently accompanied by dizziness. Circulation disorders are the most common causes of dizziness. Other causes are head injury , ear infection, allergies , and nervous system disorders.

Dizziness often disappears without treatment or with treatment of the underlying problem, but it can be long term or chronic.

Demographics

According to the National Institutes of Health, 42 percent of Americans seek medical help for dizziness at some point in their lives. The costs may exceed a billion dollars and account for 5 million doctor visits annually. Episodes of dizziness increase with age, and are common among the elderly.

Causes and symptoms

Careful attention to symptoms can help determine the underlying cause of the dizziness. Underlying problems may be benign and easily treated, or they may be dangerous and in need of intensive therapy. Not all cases of dizziness can be linked to a specific cause. More than one type of dizziness can be experienced at the same time, and symptoms may be mixed. Episodes of dizziness may last for a few seconds or for days. The length of an episode is related to the underlying cause.

The symptoms of syncope include dimmed vision, loss of coordination, confusion, lightheadedness, and sweating. These symptoms can lead to a brief loss of consciousness or fainting. They are related to a reduced flow of blood to the brain; they often occur when a person is standing up and can be relieved by sitting or lying down. Vertigo is characterized by a sensation of spinning or turning, accompanied by nausea , vomiting , ringing in the ears, headache , or fatigue. An individual may have trouble walking, remaining coordinated, or keeping balance. Nonsyncope nonvertigo dizziness is characterized by a feeling of being off balance that becomes worse if the individual tries moving or performing detail-intense tasks.

A person may experience dizziness for many reasons. Syncope is associated with low blood pressure, heart problems, and disorders in the autonomic nervous system, the system of involuntary functions such as breathing. Syncope may also arise from emotional distress, pain , and other reactions to outside stressors. Nonsyncope nonvertigo dizziness may be caused by rapid breathing, low blood sugar, or migraine headache, or by more serious medical conditions.

Vertigo is often associated with inner ear problems called vestibular disorders. A particularly intense vestibular disorder, Meniere's disease, interferes with the volume of fluid in the inner ear. This disease, which affects approximately one in every 1,000 people, causes intermittent vertigo over the course of weeks, months, or years. Meniere's disease is often accompanied by ringing or buzzing in the ear, hearing loss, and a feeling that the ear is blocked. Damage to the nerve that leads from the ear to the brain can also cause vertigo. Such damage can result from head injury or a tumor. An acoustic neuroma, for example, is a benign tumor that wraps around the nerve. Vertigo can also be caused by disorders of the central nervous system and the circulatory system, such as hardening of the arteries (arteriosclerosis), stroke , or multiple sclerosis.

Some medications cause changes in blood pressure or blood flow. These medications can cause dizziness in some people. Prescription medications carry warnings of such side effects, but common drugs, such as caffeine or nicotine, can also cause dizziness. Certain antibiotics can damage the inner ear and cause hearing loss and dizziness.

Diet may cause dizziness. The role of diet may be direct, as through alcohol intake. It may be also be indirect, as through arteriosclerosis caused by a high-fat diet. Some people experience a slight dip in blood sugar and mild dizziness if they miss a meal, but this condition is rarely dangerous unless the person is diabetic. Food sensitivities or allergies can also be a cause of dizziness. Chronic conditions, such as heart disease, and serious acute problems, such as seizures and strokes, can cause dizziness. However, such conditions usually exhibit other characteristic symptoms.

When to call the doctor

A doctor should be called whenever a person experiences dizziness or other unusual state of mental confusion that does not spontaneously resolve within a few minutes.

Diagnosis

During the initial medical examination, an individual with dizziness should provide a detailed description of the type of dizziness experienced, when it occurs, and how often each episode lasts. A diary of symptoms may help track this information. The person should report any symptoms that accompany the dizziness, such as a ringing in the ear or nausea, any recent injury or infection, and any medication taken.

Blood pressure, pulse, respiration, and body temperature are checked, and the ear, nose, and throat are scrutinized. The sense of balance is assessed by moving the individual's head to various positions or by tilt-table testing. (In tilt-table testing, the person lies on a table that can be shifted into different positions and reports any dizziness that occurs.)

Further tests may be indicated by the initial examination. Hearing tests help assess ear damage. X rays , computed tomography scan (CT scan), and magnetic resonance imaging (MRI) can pinpoint evidence of nerve damage, tumor, or other structural problems. If a vestibular disorder is suspected, a technique called electronystagmography (ENG) may be used. ENG measures the electrical impulses generated by eye movements. Blood tests can determine diabetes, high cholesterol , and other diseases. In some cases, a heart evaluation may be useful. Despite thorough testing, however, an underlying cause cannot always be determined.

Treatment

Treatment is determined by the underlying cause. If an individual has a cold or influenza , a few days of bed rest is usually adequate to resolve dizziness. Other causes of dizziness, such as mild vestibular system damage, may resolve without medical treatment.

If dizziness continues, drug therapy may prove helpful. Because circulatory problems often cause dizziness, medication may be prescribed to control blood pressure or to treat arteriosclerosis. Sedatives may be useful to relieve the tension that can trigger or aggravate dizziness. Low blood sugar associated with diabetes sometimes causes dizziness and is treated by controlling blood sugar levels. An individual may be asked to avoid caffeine, nicotine, alcohol, and those substances that cause allergic reactions. A low-salt diet may also help some people.

When other measures have failed, surgery may be suggested to relieve pressure on the inner ear. If the dizziness is not treatable by drugs, surgery, or other means, physical therapy may be used and the person may be taught coping mechanisms for the problem.

Because dizziness may arise from serious conditions, it is advisable to seek medical treatment. Alternative treatments can often be used alongside conventional medicine without conflict. Relaxation techniques, such as yoga and massage therapy , that focus on relieving tension are popularly recommended methods for reducing stress. Aroma therapists recommend a warm bath scented with essential oils of lavender, geranium, and sandalwood.

Homeopathic therapies can work very effectively for dizziness and are especially applicable when no organic cause can be identified. An osteopath or chiropractor may suggest adjustments of the head, jaw, neck, and lower back to relieve pressure on the inner ear. Acupuncturists also offer some treatment options for acute and chronic cases of dizziness. Nutritionists may be able to offer advice and guidance in choosing dietary supplements, identifying foods to avoid and balancing nutritional needs.

Prognosis

Outcome depends on the cause of dizziness. Controlling or curing the underlying factors usually relieves dizziness. In some cases, dizziness disappears without treatment. In a few cases, dizziness can become a permanent disabling condition and a person's options are limited.

Prevention

Most people learn through experience that certain activities make them dizzy and they learn to avoid them. For example, if reading in a car produces motion sickness, an individual leaves reading materials for after arrival. Changes to the diet can also cut down on episodes of dizziness in susceptible people. Relaxation techniques can help ward off tension and anxiety that can cause dizziness.

These techniques can help minimize or even prevent dizziness for people with chronic diseases. For example, persons with Meniere's disease may avoid episodes of vertigo by omitting salt, alcohol, and caffeine from their diets. Reducing blood cholesterol can help diminish arteriosclerosis and indirectly treat dizziness.

Some cases of dizziness cannot be prevented. Acoustic neuromas, for example, were not as of 2004 predictable or preventable. When the underlying cause of dizziness cannot be discovered, it may be difficult to recommend preventive measures. Alternative approaches designed to rebalance the body's energy flow, such as acupuncture and constitutional homeopathy, may be helpful in cases where the cause of dizziness cannot be pinpointed.

Nutritional concerns

Persons who experience dizziness should limit alcohol intake and avoid diets that are high in fat. Persons with diabetes should eat their meals on a regular schedule. People for whom some foods cause allergic reactions or sensitivities or dizziness, should avoid consuming the offending substances.

Parental concerns

Parents should be alert for complaints from their children of dizziness or other states of mental confusion that do not spontaneously resolve within a minute or so.

KEY TERMS

Acoustic neuroma A benign tumor that grows on the nerve leading from the inner ear to the brain. As the tumor grows, it exerts pressure on the inner ear and causes severe vertigo.

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.

Autonomic nervous system The part of the nervous system that controls so-called involuntary functions, such as heart rate, salivary gland secretion, respiratory function, and pupil dilation.

Computed tomography (CT) An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body's internal structures; also called computed axial tomography.

Electronystagmography A method for measuring the electricity generated by eye movements. Electrodes are placed on the skin around the eye and the individual is subjected to a variety of stimuli so that the quality of eye movements can be assessed.

Magnetic resonance imaging (MRI) An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct detailed images of internal body structures and organs, including the brain.

Vestibular system The brain and parts of the inner ear that work together to detect movement and position.

Resources

BOOKS

Benditt, David G. Evaluation and Treatment of Syncope: A Handbook for Clinical Practice. Malden, MA: Blackwell, 2003.

Daroff, Robert B., and Mark D. Carlson. "Faintness, Syncope, Dizziness, and Vertigo." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al., New York: McGraw-Hill, 2001, pp. 1118.

Grubb, Blair P., and Mary C. McMann. Fainting Phenomenon: Understanding Why People Faint and What Can Be Done about It. Malden, MA: Futura Publishing, 2001.

The Official Patient's Sourcebook on Syncope: A Revised and Updated Directory for the Internet Age. San Diego, CA: ICON Health Publications, 2003.

Simon, Roger P. "Syncope." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 226871.

PERIODICALS

Chamelian, L., and A. Feinstein. "Outcome after mild to moderate traumatic brain injury: The role of dizziness." Archives of Physical Medicine and Rehabilitation 85, no. 10 (2004): 16626.

Heid, L., et al. "Vertigo, dizziness, and tinnitus after otobasal fractures." International Tinnitus Journal 10, no. 1 (2004): 94100.

ORGANIZATIONS

American Academy of Neurology. 1080 Montreal Avenue, St. Paul, MN 55116. Web site: <www.aan.com/>.

American Academy of Pediatrics. 141 Northwest Point Blvd., Elk Grove Village, IL 600071098. Web site: <www.aap.org>.

American Council for Headache Education. 19 Mantua Rd., Mt. Royal, NJ 08061. Web site: <www.achenet.org>.

WEB SITES

"Dizziness." Mayo Clinic, August 6, 2004. Available online at <www.mayoclinic.com/invoke.cfm?id=DS00435> (accessed January 5, 2005).

"Dizziness and Motion Sickness." American Academy of Otolaryngology/Head and Neck Surgery. Available online at <www.entnet.org/healthinfo/balance/dizziness.cfm> (accessed January 5, 2005).

"Dizziness and Vertigo." MedlinePlus. Available online at <www.nlm.nih.gov/medlineplus/dizzinessandvertigo.html> (accessed January 5, 2005).

"Dizziness and Vertigo." National Multiple Sclerosis Society, March 2003. Available online at <www.nationalmssociety.org/Sourcebook-Dizziness.asp> (accessed January 5, 2005).

L. Fleming Fallon, Jr., MD, DrPH

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Fallon, L.. "Dizziness." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 28 Aug. 2016 <http://www.encyclopedia.com>.

Fallon, L.. "Dizziness." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. (August 28, 2016). http://www.encyclopedia.com/doc/1G2-3447200196.html

Fallon, L.. "Dizziness." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Retrieved August 28, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3447200196.html

Dizziness

Dizziness

Definition

Dizziness is classified into three categoriesvertigo, syncope, and nonsyncope nonvertigo. Each category has a characteristic set of symptoms, all related to the sense of balance. In general, syncope is defined by a brief loss of consciousness (fainting) or by dimmed vision and feeling uncoordinated, confused, and lightheaded. Many people experience a sensation like syncope when they stand up too fast. Vertigo is the feeling that either the individual or the surroundings are spinning. This sensation is like being on a spinning amusement park ride. Individuals with nonsyncope nonvertigo dizziness feel as though they cannot keep their balance. This sensation may become worse with movement.

Description

The brain coordinates information from the eyes, the inner ear, and the body's senses to maintain balance. If any of these sources of information is disrupted, the brain may not be able to compensate. For example, people sometimes experience motion sickness because the information from their body tells the brain that they are sitting still, but information from the eyes indicates that they are moving. The messages don't correspond and dizziness results.

Vision and the body's senses are the most important systems for maintaining balance, but problems in the inner ear are the most frequent cause of dizziness. The inner ear, also called the vestibular system, contains fluid that helps to fine tune the information the brain receives from the eyes and the body. When fluid volume or pressure in the inner ear changes, information about balance is altered. The discrepancy gives conflicting messages to the brain about balance and induces dizziness.

Certain medical conditions can cause dizziness because they affect the systems that maintain balance. For example, the inner ear is very sensitive to changes in blood flow. Because such medical conditions as high blood pressure or low blood sugar can affect blood flow, these conditions are frequently accompanied by dizziness. Circulation disorders are the most common causes of dizziness. Other causes are head injuries, ear infections, allergies , and nervous system disorders.

Dizziness often disappears without treatment or with treatment of the underlying problem, but it can be long-term or chronic. According to the National Institutes of Health, 42% of Americans will seek medical help for dizziness at some point in their lives. The costs may exceed a billion dollars and account for five million visits to physicians annually. Episodes of dizziness increase with age. Among people aged 75 or older, dizziness is the most frequent reason for seeing a doctor.

Causes & symptoms

Careful attention to symptoms can help determine the underlying cause of the dizziness. The underlying problems may be benign and easily treated, or they may be dangerous and require intensive therapy. Not all cases of dizziness can be linked to a specific cause. More than one type of dizziness can be experienced at the same time and symptoms may be mixed. Episodes of dizziness may last for a few seconds or for days. The length of an episode is related to the underlying cause.

The symptoms of syncope include dimmed vision, loss of coordination, confusion, lightheadedness, and sweating. These symptoms can lead to a brief loss of consciousness or fainting. They are related to a reduced flow of blood to the brain; they often occur when a person is standing up and can be relieved by sitting or lying down. Vertigo is characterized by a sensation of spinning or turning, accompanied by nausea, vomiting , ringing in the ears, headache , or fatigue . An individual may have trouble walking, remaining coordinated, or keeping balance. Nonsyncope nonvertigo dizziness is characterized by a feeling of being off balance that becomes worse if the individual tries moving or performing detail-intense tasks.

A person may experience dizziness for many reasons. Syncope is associated with low blood pressure, heart problems, and disorders in the autonomic nervous system, which controls such involuntary functions as breathing. Syncope may also arise from emotional distress, pain , and other reactions to outside stressors. Nonsyncope nonvertigo dizziness may be caused by rapid breathing, low blood sugar, or migraine headache , as well as by more serious medical conditions.

Vertigo is often associated with inner ear problems called vestibular disorders. A particularly intense vestibular disorder, Ménière's disease , interferes with the volume of fluid in the inner ear. This disease, which affects approximately one in every 1,000 people, causes intermittent vertigo over the course of weeks, months, or years. Ménière's disease is often accompanied by ringing or buzzing in the ear, hearing loss , and a feeling that the ear is blocked. Damage to the nerve that leads from the ear to the brain can also cause vertigo. Such damage can result from head injury or a tumor. An acoustic neuroma, for example, is a benign tumor that wraps around the nerve. Vertigo can also be caused by disorders of the central nervous system and the circulation, such as hardening of the arteries (arteriosclerosis), stroke , or multiple sclerosis .

Some medications cause changes in blood pressure or blood flow. These medications can cause dizziness in some people. Prescription medications carry warnings of such side effects, but common drugs such as caffeine or nicotine can also cause dizziness. Certain antibiotics can damage the inner ear and cause hearing loss and dizziness.

Diet may cause dizziness. The role of diet may be direct, as through alcohol intake. It may be also be indirect, as through arteriosclerosis caused by a high-fat diet. Some people experience a slight dip in blood sugar and mild dizziness if they miss a meal, but this condition is rarely dangerous unless the person is diabetic. Food sensitivities or allergies can also be a cause of dizziness. Such chronic conditions as heart disease and serious acute problems such as seizures and strokes can cause dizziness. These conditions, however, usually exhibit other characteristic symptoms.

Diagnosis

During the initial medical examination, an individual with dizziness should provide a detailed description of the type of dizziness experienced, when it occurs, and how often each episode lasts. A diary of symptoms may help to track this information. The patient should report any symptoms that accompany the dizziness, such as ringing in the ear or nausea, any recent injury or infection, and any medication taken.

The examiner will check the patient's blood pressure, pulse, respiration, and body temperature as well as the ear, nose, and throat. The sense of balance is assessed by moving the individual's head to various positions or by tilt-table testing. In tilt-table testing, the person lies on a table that can be shifted into different positions and reports any dizziness that occurs.

Further tests may be indicated by the initial examination. Hearing tests help assess ear damage. X rays, computed tomography scan (CT scan), and magnetic resonance imaging (MRI) can pinpoint evidence of nerve damage, tumors, or other structural problems. If a vestibular disorder is suspected, a technique called electronystagmography (ENG) may be used. ENG measures the electrical impulses generated by eye movements. Blood tests can determine diabetes, high cholesterol , and other diseases. In some cases, a heart evaluation may be useful. Despite thorough testing, however, an underlying cause cannot always be determined.

Doctors caution that childhood syncope (fainting), although rarely serious, can indicate a serious cardiac. If the fainting is abrupt or happens with exertion, it may indicate a more serious problem.

Treatment

Because dizziness may arise from serious conditions, it is advisable to seek medical treatment. Alternative treatments can often be used alongside conventional medicine without conflict. Potentially beneficial therapies include nutritional therapy, herbal remedies, homeopathy, aromatherapy, osteopathy, acupuncture, acupressure , and relaxation techniques.

Nutritional therapy

To prevent dizziness, nutritionists often advise eating smaller but more frequent meals and avoiding caffeine, nicotine, alcohol, foods high in fat or sugar, or any substances that cause allergic reactions. A low-salt diet may also be helpful to some people. Nutritionists may also recommend certain dietary supplements:

  • Magnesium citrate, aspartate or maleate: for dizziness caused by magnesium deficiency.
  • B-complex vitamins, especially vitamin B12: for dizziness caused by deficiency of these essential vitamins.

Herbal remedies

The following herbs have been used to treat dizziness symptoms:

  • Ginger: for treatment of dizziness caused by nausea.
  • Ginkgo biloba: may decrease dizziness by increasing blood flow to the brain.

Homeopathy

Homeopathic therapies can work very effectively for dizziness, and are especially applicable when no organic cause can be identified. They are chosen according to the patient's specific symptom profile:

  • Aconite: for feeling light-headed from postural hypotension (getting up too quickly)
  • Coccolus: for motion sickness or syncope
  • Conium maculatum: for feeling dizzy while looking at rapidly-moving images.
  • Gelsemium: for feeling light-headed and out of balance, often associated with influenza or stage fright.
  • Petroleum: for dizziness upon standing up too fast and headache before and after a storm.

Aromatherapy

Aromatherapists recommend a warm bath scented with essential oils of lavender , geranium, and sandalwood as treatment for dizziness. This therapy can have a calming effect on the nervous system.

Osteopathy

An osteopath or chiropractor may suggest manipulations or adjustments of the head, jaw, neck, and lower back to relieve pressure on the inner ear.

Acupressure

Acupressure may be able to improve circulation and decrease the symptoms of vertigo. The Neck Release, which involves pressing on five pairs of points on the shoulder blades and neck, is helpful for dizziness associated with migraine headaches.

Relaxation techniques

Relaxation techniques, such as yoga, meditation , and massage therapy for relieving tension, are popularly recommended methods for reducing stress .

Allopathic treatment

Treatment of dizziness is determined by the underlying cause. If an individual has a cold or influenza, a few days of bed rest is usually adequate to resolve dizziness. Other causes of dizziness, such as mild vestibular system damage, may resolve without medical treatment. If dizziness continues, drug therapy may be required to treat such underlying illnesses as high blood pressure, arteriosclerosis, nervous conditions or diabetes. A physician may also prescribe antibiotics if ear infections are suspected. Selective serotonin reuptake inhibitors (SSRIs) have recently been shown to relieve dizziness in patients who have psychiatric symptoms. When other measures have failed, surgery may be suggested to relieve pressure on the inner ear. If the dizziness is not treatable by drugs, surgery, or other means, physical therapy may be used and the patient may be taught coping mechanisms for the problem.

Expected results

The outcome of treatment depends on the cause of dizziness. Controlling or curing the underlying factors usually relieves the dizziness itself. In some cases, the symptoms disappear without treatment. In a few cases, dizziness can become a permanent disabling condition.

Prevention

Most people learn through experience that certain activities will make them dizzy and they learn to avoid them. For example, if reading in a car produces motion sickness, reading should be postponed until after the trip. Changes in diet can also cut down on episodes of dizziness in susceptible people. For example, persons with Ménière's disease may avoid episodes of vertigo by leaving salt, alcohol, and caffeine out of their diets . Reducing blood cholesterol can help diminish arteriosclerosis and indirectly treat dizziness. Daily multiple vitamin and mineral supplements may help prevent dizziness caused by deficiencies of these essential nutrients. Relaxation techniques can help ward off tension and anxiety that can cause dizziness.

Some cases of dizziness cannot be prevented. Acoustic neuromas, for example, are not predictable or preventable. Alternative approaches designed to rebalance the body's energy flow, such as acupuncture and constitutional homeopathy, may be helpful in cases where the cause of dizziness cannot be pinpointed.

Resources

BOOKS

Cameron, Myra. Lifetime Encyclopedia of Natural Remedies. Paramus, NJ: Prentice Hall, 1993.

Yardley, Lucy. Vertigo and Dizziness. New York: Routledge, 1994.

Zand, Janet, Allan N. Spreen, and James B. LaValle. Smart Medicine for Healthier Living: A Practical A-Z Reference to Natural and Conventional Treatments for Adults. Garden City Park, NY: Avery Publishing Group, 1999.

PERIODICALS

Ohnson, Kate. "Fainting Usually is Benign, but it can be Fatal." Pediatric News (July 2002):25.

PERIODICALS

"SSRIs Relieve Dizziness in Psyciatric Patients." Critical Care Alert (August 2002):2.

ORGANIZATIONS

Ménière's Network. 2000 Church St., P.O. Box 111, Nashville, TN 37236. (800) 545-4327.

The Vestibular Disorders Association. P.O. Box 4467, Portland, OR 97208-4467. (503) 229-7705. http://www.teleport.com/~veda/.

Mai Tran

Teresa G. Odle

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Tran, Mai; Odle, Teresa. "Dizziness." Gale Encyclopedia of Alternative Medicine. 2005. Retrieved August 28, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3435100268.html

Dizziness

Dizziness

Definition

As a disorder, dizziness is classified into three categories-vertigo, syncope, and nonsyncope nonvertigo. Each category has a characteristic set of symptoms, all related to the sense of balance. In general, syncope is defined by a brief loss of consciousness (fainting ) or by dimmed vision and feeling uncoordinated, confused, and lightheaded. Many people experience a sensation like syncope when they stand up too fast. Vertigo is the feeling that either the individual or the surroundings are spinning. This sensation is like being on a spinning amusement park ride. Individuals with nonsyncope nonvertigo dizziness feel as though they cannot keep their balance. This feeling may become worse with movement.

Description

The brain coordinates information from the eyes, the inner ear, and the body's senses to maintain balance. If any of these information sources is disrupted, the brain may not be able to compensate. For example, people sometimes experience motion sickness because the information from their body tells the brain that they are sitting still, but information from the eyes indicates that they are moving. The messages do not correspond and dizziness results.

Vision and the body's senses are the most important systems for maintaining balance, but problems in the inner ear are the most frequent cause of dizziness. The inner ear, also called the vestibular system, contains fluid that helps fine tune the information the brain receives from the eyes and the body. When fluid volume or pressure in one inner ear changes, information about balance is altered. The discrepancy gives conflicting messages to the brain about balance and induces dizziness.

Certain medical conditions can cause dizziness, because they affect the systems that maintain balance. For example, the inner ear is very sensitive to changes in blood flow. Because medical conditions such as high blood pressure or low blood sugar can affect blood flow, these conditions are frequently accompanied by dizziness. Circulation disorders are the most common causes of dizziness. Other causes are head injury, ear infection, allergies, and nervous system disorders.

Dizziness often disappears without treatment or with treatment of the underlying problem, but it can be long term or chronic. According to the National Institutes of Health, 42% of Americans will seek medical help for dizziness at some point in their lives. The costs may exceed a billion dollars and account for five million doctor visits annually. Episodes of dizziness increase with age. Among people aged 75 or older, dizziness is the most frequent reason for seeing a doctor.

Causes and symptoms

Careful attention to symptoms can help determine the underlying cause of the dizziness. Underlying problems may be benign and easily treated or they may be dangerous and in need of intensive therapy. Not all cases of dizziness can be linked to a specific cause. More than one type of dizziness can be experienced at the same time and symptoms may be mixed. Episodes of dizziness may last for a few seconds or for days. The length of an episode is related to the underlying cause.

The symptoms of syncope include dimmed vision, loss of coordination, confusion, lightheadedness, and sweating. These symptoms can lead to a brief loss of consciousness or fainting. They are related to a reduced flow of blood to the brain; they often occur when a person is standing up and can be relieved by sitting or lying down. Vertigo is characterized by a sensation of spinning or turning, accompanied by nausea, vomiting, ringing in the ears, headache, or fatigue. An individual may have trouble walking, remaining coordinated, or keeping balance. Nonsyncope nonvertigo dizziness is characterized by a feeling of being off balance that becomes worse if the individual tries moving or performing detail-intense tasks.

A person may experience dizziness for many reasons. Syncope is associated with low blood pressure, heart problems, and disorders in the autonomic nervous system, the system of involuntary functions such as breathing. Syncope may also arise from emotional distress, pain, and other reactions to outside stressors. Nonsyncope nonvertigo dizziness may be caused by rapid breathing, low blood sugar, or migraine headache, as well as by more serious medical conditions.

Vertigo is often associated with inner ear problems called vestibular disorders. A particularly intense vestibular disorder, Méniére's disease, interferes with the volume of fluid in the inner ear. This disease, which affects approximately one in every 1,000 people, causes intermittent vertigo over the course of weeks, months, or years. Méniére's disease is often accompanied by ringing or buzzing in the ear, hearing loss, and a feeling that the ear is blocked. Damage to the nerve that leads from the ear to the brain can also cause vertigo. Such damage can result from head injury or a tumor. An acoustic neuroma, for example, is a benign tumor that wraps around the nerve. Vertigo can also be caused by disorders of the central nervous system and the cirulatory system, such as hardening of the arteries (arteriosclerosis), stroke, or multiple sclerosis.

Some medications cause changes in blood pressure or blood flow. These medications can cause dizziness in some people. Prescription medications carry warnings of such side effects, but common drugs, such as caffeine or nicotine, can also cause dizziness. Certain antibiotics can damage the inner ear and cause hearing loss and dizziness.

Diet may cause dizziness. The role of diet may be direct, as through alcohol intake. It may be also be indirect, as through arteriosclerosis caused by a high-fat diet. Some people experience a slight dip in blood sugar and mild dizziness if they miss a meal, but this condition is rarely dangerous unless the person is diabetic. Food sensitivities or allergies can also be a cause of dizziness. Chronic conditions, such as heart disease, and serious acute problems, such as seizures and strokes, can cause dizziness. However, such conditions usually exhibit other characteristic symptoms.

Diagnosis

During the initial medical examination, an individual with dizziness should provide a detailed description of the type of dizziness experienced, when it occurs, and how often each episode lasts. A diary of symptoms may help track this information. Report any symptoms that accompany the dizziness, such as a ringing in the ear or nausea, any recent injury or infection, and any medication taken.

Blood pressure, pulse, respiration, and body temperature are checked, and the ear, nose, and throat are scrutinized. The sense of balance is assessed by moving the individual's head to various positions or by tilt-table testing. In tilt-table testing, the person lies on a table that can be shifted into different positions and reports any dizziness that occurs.

Further tests may be indicated by the initial examination. Hearing tests help assess ear damage. X rays, computed tomography scan (CT scan), and magnetic resonance imaging (MRI) can pinpoint evidence of nerve damage, tumor, or other structural problems. If a vestibular disorder is suspected, a technique called electronystagmography (ENG) may be used. ENG measures the electrical impulses generated by eye movements. Blood tests can determine diabetes, high cholesterol, and other diseases. In some cases, a heart evaluation may be useful. Despite thorough testing, an underlying cause cannot always be determined.

Treatment

Treatment is determined by the underlying cause. If an individual has a cold or influenza, a few days of bed rest is usually adequate to resolve dizziness. Other causes of dizziness, such as mild vestibular system damage, may resolve without medical treatment.

If dizziness continues, drug therapy may prove helpful. Because circulatory problems often cause dizziness, medication may be prescribed to control blood pressure or to treat arteriosclerosis. Sedatives may be useful to relieve the tension that can trigger or aggravate dizziness. Low blood sugar associated with diabetes sometimes causes dizziness and is treated by controlling blood sugar levels. An individual may be asked to avoid caffeine, nicotine, alcohol, and any substances that cause allergic reactions. A low-salt diet may also help some people.

When other measures have failed, surgery may be suggested to relieve pressure on the inner ear. If the dizziness is not treatable by drugs, surgery, or other means, physical therapy may be used and the patient may be taught coping mechanisms for the problem.

Alternative treatment

Because dizziness may arise from serious conditions, it is advisable to seek medical treatment. Alternative treatments can often be used alongside conventional medicine without conflict. Relaxation techniques, such as yoga and massage therapy that focus on relieving tension, are popularly recommended methods for reducing stress. Aromatherapists recommend a warm bath scented with essential oils of lavender, geranium, and sandalwood.

Homeopathic therapies can work very effectively for dizziness, and are especially applicable when no organic cause can be identified. An osteopath or chiropractor may suggest adjustments of the head, jaw, neck, and lower back to relieve pressure on the inner ear. Acupuncturists also offer some treatment options for acute and chronic cases of dizziness. Nutritionists may be able to offer advice and guidance in choosing dietary supplements, identifying foods to avoid, and balancing nutritional needs.

Prognosis

Outcome depends on the cause of dizziness. Controlling or curing the underlying factors usually relieves dizziness. In some cases, dizziness disappears without treatment. In a few cases, dizziness can become a permanent disabling condition and a person's options are limited.

Prevention

Most people learn through experience that certain activities will make them dizzy and they learn to avoid them. For example, if reading in a car produces motion sickness, an individual leaves reading materials for after the trip. Changes to the diet can also cut down on episodes of dizziness in susceptible people. Relaxation techniques can help ward off tension and anxiety that can cause dizziness.

These techniques can help minimize or even prevent dizziness for people with chronic diseases. For example, persons with Méniére's disease may avoid episodes of vertigo by leaving salt, alcohol, and caffeine out of their diets. Reducing blood cholesterol can help diminish arteriosclerosis and indirectly treat dizziness.

Some cases of dizziness cannot be prevented. Acoustic neuromas, for example, are not predictable or preventable. When the underlying cause of dizziness cannot be discovered, it may be difficult to recommend preventive measures. Alternative approaches designed to rebalance the body's energy flow, such as acupuncture and constitutional homeopathy, may be helpful in cases where the cause of dizziness cannot be pinpointed.

KEY TERMS

Acoustic neuroma A benign tumor that grows on the nerve leading from the inner ear to the brain. As the tumor grows, it exerts pressure on the inner ear and causes severe vertigo.

Arteriosclerosis Hardening of the arteries caused by high blood cholesterol and high blood pressure.

Autonomic nervous system The part of the nervous system that controls involuntary functions such as breathing and heart beat.

Computed tomography (CT) An imaging technique in which cross-sectional x rays of the body are compiled to create a three-dimensional image of the body's internal structures.

Electronystagmography A method for measuring the electricity generated by eye movements. Electrodes are placed on the skin around the eye and the individual is subjected to a variety of stimuli so that the quality of eye movements can be assessed.

Magnetic resonance imaging (MRI) An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct images of internal structures.

Vestibular system The area of the inner ear that helps maintain balance.

Resources

ORGANIZATIONS

Méniére's Network. 1817 Patterson St., Nashville, TN 37203. (800) 545-4327. http://www.earfoundation.org.

Vestibular Disorders Association. PO Box 4467, Portland, OR 97208-4467. (503) 229-7705. veda">http://www.teleport.com/veda.

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Barrett, Julia. "Dizziness." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Retrieved August 28, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3451600525.html

Dizziness

DIZZINESS

Dizziness is a common medical problem. Thirty percent of people over age sixty-five complain of dizziness and 20 percent of all older persons experience dizziness severe enough to seek medical advice.

The syndrome of dizziness is varied and encompasses a wide range of symptoms. Getting a precise and accurate description of the individual's symptoms is therefore essential for making an accurate diagnosis and helps to differentiate between the four medical subtypes traditionally considered to be the most common causes of dizziness: vertigo, presyncope, dysequilibrium, and light-headedness.

Causes of dizziness

Vertigo is the illusion of movement of either the body or environment. This symptom is often described using terms such as spinning, turning, reeling, or any other depiction of movement. Most commonly, vertigo is due to a problem within the inner ear or the vestibular nerve, which is the nerve that helps to maintain balance. Benign positional vertigo, an illness caused by free-floating particles within the inner ear, can be diagnosed by its characteristic symptoms. With this illness, vertigo is provoked by changing position or moving the head, and symptoms usually last thirty seconds to several minutes. On the other hand, vestibular neuronitis, also called acute labyrinthitis or vestibulitis, usually causes a single episode of vertigo that may last from one day to several months. Vestibular neuronitis is thought to be caused by a viral infection. Another illness of the inner ear, Meniere's disease, can be differentiated by its long duration and associated hearing loss. Sometimes, vertigo can be caused by a central problem within the brain, such as a stroke.

The term presyncope refers to near fainting. People describe this as "blacking out" or "nearly fainting." There are many causes of presyncope, such as abnormal heart rhythms, medication, problems with internal blood pressure control (carotid hypersensitivity), and volume depletion. Not uncommonly, presyncope will occur without an identifiable underlying medical illness or specific cause.

The two remaining subtypes of dizziness, dysequilibrium and light-headedness, are less specific and in many cases the cause of these complaints cannot be accurately determined. The term dysequilibrium refers to a feeling of imbalance. The subtype of light-headedness is reserved for symptoms of dizziness that do not fit into any of the three other categories.

Although these subtypes of dizziness account for some causes of dizziness, it is not always possible to classify symptoms in a given individual. Often, one simple cause cannot be found to explain why dizziness is occurring and frequently there are several contributing causes, none of which alone would pose a problem. In combination, however, these factors produce the sensation of dizziness. Common contributors to dizziness include medication, impaired balance, heart disease, visual impairment, hearing loss, blood pressure that drops upon standing (i.e., orthostatic hypotension), decreased sensation in the feet, and chronic medical problems. Other cited causes of dizziness include psychiatric problems, hyperventilation, seizures, and disorders of the neck.

Evaluation

The tests needed to evaluate dizziness will depend on the information gathered during the clinical interview. Confirmation of the clinical diagnosis through physical examination and laboratory testing is necessary. In order to document whether there is a fall in blood pressure as the person stands up, examination should include blood pressure measurement in the lying and standing positions. Checking for vestibular abnormalities, examining vision, observing gait, and looking for neurologic abnormalities can be helpful. Important laboratory tests include measures of blood cell counts, thyroid function, blood chemistry (such as sodium), kidney function, calcium, and liver function. Sometimes additional tests may be needed to clarify the diagnosis. These could include tests of hearing and vestibular function, monitoring heart rhythm, evaluation of hearing, or CT or MRI scanning of the head.

Treatment

Management of dizziness will depend upon the subtype and causes identified. Antivertigo medications, such antihistamines and others, can be used to treat the debilitating symptoms of vestibular neuronitis, such as nausea, vomiting, and the sensation of movement. These treatments should be used for short periods of time and withdrawn as soon as symptoms improve. Side effects of these medications include stomach upset, fatigue, and confusion. For benign positional vertigo, there is evidence that antivertigo medications may delay improvement. In this circumstance, vestibular desensitization, such as rapidly tilting the body from one side to the other, may alleviate symptoms. Meniere's disease is treated with salt restriction, diuretic therapy, surgery, or antivertigo medications. Most of these treatments have uncertain benefits and are generally recommended only for short-term use. Aspirin, or another medication with antiplatelet effect, is recommended for stroke-related vertigo.

Treatment of dizziness caused by presyncope involves identifying whether or not there is an underlying cause. Presyncope may be caused by medications that lower blood pressure or cause dehydration (diuretics), or by medical illnesses, such as blood loss or arrhythmias. In these cases the identified problem should be appropriately treated. Information about treating presyncope that is associated with a drop in blood pressure when standing can be found in the section on fainting.

In many instances, a single cause of dizziness will not explain the symptoms and the focus of treatment will involve correcting as many contributing problems as possible. Offending medications should be stopped, gradually decreased, or replaced. Correcting vision and optimizing health status may be helpful. Exercise and walking aids may ameliorate problems of balance.

Conclusion

Dizziness is a common and challenging problem for an elderly person, which requires a systematic and detailed approach. Once medical problems are identified, treatment requires careful management of each difficulty identified, with fastidious follow-up to determine whether treatment is effective or producing side effects. In some circumstances, dizziness will not respond to treatment, in which case supportive therapy will be necessary.

Laurie Herzig Mallery

See also Balance and Mobility; Fainting; Hearing.

BIBLIOGRAPHY

Colledge, N. R.; Wilson, J. A.; MacIntyre, C. C. A.; and MacLennan, W. J. "The Prevalence and Characteristics of Dizziness in an Elderly Community." Age and Ageing 23 (1994): 117120.

Furman, J. M., and Cass, S. P. "Benign Paroxysmal Positional Vertigo." The New England Journal of Medicine 341, no. 21 (1999): 15901596.

Sloane, Philip; Blazer, Dan; and George, Lindak. "Dizziness in a Community Elderly Population." Journal of the American Geriatric Society 37 (1989): 101108.

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dizziness

dizziness The term ‘dizziness’ is used to describe both ‘lightheadedness’ and vertigo. Lightheadedness may consist of a clouding of consciousness, a difficulty in focusing rational thought, or a difficulty in concentrating. Vertigo is the illusion of movement either of oneself or of the surroundings.

The illusion of movement, when the neighbouring train departs the station, or the feeling of being drawn toward the ground or the sea when standing on a high point, are recognized by many. The feeling of falling is a part of our dreams. We enjoy the illusion of movement in 3-D and circular surround cinemas. Children enjoy the vertigo they can trigger by spinning on the spot. All these are perceptions we have in the absence of illness, but many people experience dizziness as part of an illness, which can ruin their quality of life and lead to a loss of independence. Lightheadedness and vertigo can lead to a final common pathway of anxiety and hyperventilation, resulting in a spiral of deteriorating lightheadedness. This overlap of symptoms and the final common pathway justify the acceptance of the term ‘dizziness’.

Balance information is processed within the vestibular nuclei of the brain stem. Inputs include the sensory organs of the ears and eyes, proprioceptive and tactile sense, and higher centres in the brain. There is no single area of the cerebral cortex involved with balance information alone. On the contrary, PET scanning (positron emission tomography, which ‘maps’ relative activity in the different regions of the brain) reveals that balance-related inputs influence many large areas of the cerebral cortex. Therefore, dizziness can lead to a myriad of symptoms, depending on which areas of the brain are involved. The extent of these complex connections is highlighted by the effect of stimulating the balance organs of the left ear, by running cold water into the left ear canal, in patients with left-sided sensory ‘hemi-neglect’ due to a right cerebral hemisphere stroke. For several minutes after the irrigation of the water into the left ear, during the dizziness which this causes, function may be improved in the previously numb and poorly-used left side of the body. This complex neuronal networking is also crucial to our ability to suppress dizziness with training or rehabilitation, as pilots, gymnasts, and dancers demonstrate.

Any factors that can alter the function of the many parts of the brain dealing with balance function can lead to dizziness and a variable cluster of symptoms. These include any cause of inadequate blood flow (and therefore of oxygen and glucose supply) to the brain — as for example at the onset of fainting, or in illnesses causing heart failure or obstruction of the blood vessels — or impaired nutrient supply due to decrease in blood sugar (hypoglycaemia). Inadequate brain blood flow may result from overbreathing (hyperventilation) — from whatever cause, including pain. Dizziness may also be the result of environmental agents, such as carbon monoxide poisoning from faulty domestic appliances or car exhaust fumes, which again impair the brain's oxygen supply. Likewise with other causes of oxygen shortage (hypoxia) such as high altitude or lung disease.

Damage to the balance organs themselves, as a result of trauma, infection, or other disease affecting the inner ears, may result in dizziness, though the brain has a remarkable capacity to compensate fully for such pathology. For reasons that are currently being investigated, some patients become over-reliant on visual clues for stability, and they become dizzy when they are exposed to excessive visual clues, such as in shopping malls, even when there is no definable structural pathology.

Dizziness can therefore be a manifestation of illness anywhere in the body; to determine the cause, a careful evaluation of the patient and their circumstances is essential.

Peter Savundra


See also balance; fainting; proprioception; vestibular system.

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COLIN BLAKEMORE and SHELIA JENNETT. "dizziness." The Oxford Companion to the Body. 2001. Retrieved August 28, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O128-dizziness.html

dizziness

dizziness: see vertigo.

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