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Head Injury

Head injury

Definition

Head injury is an injury to the scalp, skull, or brain. The most important consequence of head trauma is traumatic brain injury. Head injury may occur either as a closed head injury, such as the head hitting a car's windshield; or as a penetrating head injury, as when a bullet pierces the skull. Both may cause damage that ranges from mild to profound. Very severe injury can be fatal because of profound brain damage.

Description

External trauma to the head is capable of damaging the brain, even if there is no external evidence of damage. More serious injuries can cause skull fracture, blood clots between the skull and the brain, or bruising and tearing of the brain tissue itself.

Injuries to the head can be caused by traffic accidents, sports injuries , falls, workplace accidents, assaults, or bullets. Most people have had some type of head injury at least once in their lives, but rarely do they require a hospital visit.

Demographics

Each year about two million people suffer from a more serious head injury, and up to 750,000 of those are severe enough to require hospitalization . Brain injury is most likely to occur in males between ages 15 and 24, usually as a result of car and motorcycle accidents. About 70 percent of all accidental deaths are due to head injuries, as are most of the disabilities that occur after trauma. Among children and infants, head injury is the most common cause of death and disability. The most common cause of head injury in children under age two is child abuse .

Causes and symptoms

A head injury may cause damage both from the direct physical injury to the brain and from secondary factors, such as lack of oxygen, brain swelling, and disturbance of blood flow. Both closed and penetrating head injuries can cause swirling movements throughout the brain, tearing nerve fibers and causing widespread bleeding or a blood clot in or around the brain. Swelling may raise pressure within the skull (intracranial pressure) and may block the flow of oxygen to the brain.

Head trauma may cause a concussion , in which there is a brief loss of consciousness without visible structural damage to the brain. In addition to loss of consciousness, initial symptoms of brain injury may include:

  • memory loss and confusion
  • vomiting
  • dizziness
  • partial paralysis or numbness
  • shock
  • anxiety

After a head injury, there may be a period of impaired consciousness followed by a period of confusion and impaired memory with disorientation and a breakdown in the ability to store and retrieve new information. Others experience temporary amnesia following head injury that begins with memory loss over a period of weeks, months, or years before the injury (retrograde amnesia). As a person recovers, memory slowly returns. Post-traumatic amnesia refers to loss of memory for events during and after the accident.

Epilepsy occurs in 25 percent of those who have had a head injury; it is much more common in people who have had severe or penetrating injuries. Most cases of epilepsy appear right after the accident or within the first year and become less likely with increased time following the accident.

Closed head injury

Closed head injury refers to brain injury without any penetrating injury to the brain. It may be the result of a direct blow to the head; of the moving head being rapidly stopped, such as when a person's head hits a windshield in a car accident; or by the sudden deceleration of the head without its striking another object. The kind of injury the brain receives in a closed head injury is determined by whether the head was unrestrained upon impact and the direction, force, and velocity of the blow. If the head is resting on impact, the maximum damage will be found at the impact site. A moving head will cause a contrecoup injury where the brain damage occurs on the side opposite the point of impact, as a result of the brain slamming into that side of the skull. A closed head injury also may occur without the head being struck, such as when a person experiences whiplash. This type of injury occurs because the brain is of a different density than the skull and can be injured when delicate brain tissues hit against the rough, jagged inner surface of the skull.

Penetrating head injury

If the skull is fractured, bone fragments may be driven into the brain. Any object that penetrates the skull may implant foreign material and dirt into the brain, leading to an infection.

Skull fracture

A skull fracture is a medical emergency that must be treated promptly to prevent possible brain damage. Such an injury may be obvious if blood or bone fragments are visible, but it is possible for a fracture to have occurred without any apparent damage. A skull fracture should be suspected if there is:

  • blood or clear fluid leaking from the nose or ears
  • unequal pupil size
  • bruises or discoloration around the eyes or behind the ears
  • swelling or depression of part of the head

Intracranial hemorrhage

Bleeding (hemorrhage) inside the skull may accompany a head injury and cause additional damage to the brain. A blood clot (hematoma) may occur if a blood vessel between the skull and the brain ruptures; when the blood leaks out and forms a clot, it can press against brain tissue, causing symptoms from a few hours to a few weeks after the injury. If the clot is located between the bones of the skull and the covering of the brain (dura), it is called an epidural hematoma. If the clot is between the dura and the brain tissue itself, the condition is called a subdural hematoma . In other cases, bleeding may occur deeper inside the brain. This condition is called intracerebral hemorrhage or intracerebral contusion (from the word for bruising).

In any case, if the blood flow is not stopped, it can lead to unconsciousness and death. The symptoms of bleeding within the skull include:

  • nausea and vomiting
  • headache
  • loss of consciousness
  • unequal pupil size
  • lethargy

Postconcussion syndrome

If the head injury is mild, there may be no symptoms other than a slight headache. There also may be confusion, dizziness, and blurred vision. While the head injury may seem to have been quite mild, in many cases symptoms persist for days or weeks. Up to 60 percent of persons who sustain a mild brain injury continue to experience a range of symptoms called postconcussion syndrome as long as six months or a year after the injury.

The symptoms of postconcussion syndrome can result in a puzzling interplay of behavioral, cognitive, and emotional complaints that can be difficult to diagnose, including the following:

  • headache
  • dizziness
  • mental confusion
  • behavior changes
  • memory loss
  • cognitive deficits
  • depression
  • emotional outbursts

When to call the doctor

A parent of a child who has had a head injury and who is experiencing any the following symptoms should seek medical care immediately:

  • serious bleeding from the head or face
  • loss of consciousness, however brief
  • confusion and lethargy
  • lack of pulse or breathing
  • clear fluid drainage from the nose or ear

Diagnosis

The extent of damage in a severe head injury can be assessed with computed tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scans, electroencephalograms (EEG), and routine neurological and neuropsychological evaluations.

Doctors use the Glasgow Coma Scale to evaluate the extent of brain damage based on observing a person's ability to open his or her eyes, respond verbally, and respond to stimulation by moving (motor response). People can score from three to 15 points on this scale. People who score below eight when they are admitted usually have suffered a severe brain injury and will need rehabilitative therapy as they recover. In general, higher scores on the Glasgow Coma Scale indicate less severe brain injury and a better prognosis for recovery.

Individuals with a mild head injury who experience symptoms are advised to seek out the care of a specialist; unless a family physician is thoroughly familiar with medical literature in this area, experts warn that there is a good chance that people's complaints after a mild head injury will be downplayed or dismissed. In the case of mild head injury or postconcussion syndrome, CT and MRI scans, electroencephalograms (EEG), and routine neurological evaluations all may be normal because the damage is so subtle. In many cases, these tests cannot detect the microscopic damage that occurs when fibers are stretched in a mild, diffuse injury. In this type of injury, the axons lose some of their covering and become less efficient. This mild injury to the white matter reduces the quality of communication between different parts or the brain. A PET scan, which evaluates cerebral blood flow and brain metabolism, may be of help in diagnosing mild head injury.

Persons with continuing symptoms after a mild head injury should call a local chapter of a head-injury foundation that can refer people to the best nearby expert.

Treatment

If a concussion, bleeding inside the skull, or skull fracture is suspected, the person should be kept quiet in a darkened room, with head and shoulders raised slightly on pillow or blanket.

After initial emergency treatment, a team of specialists may be needed to evaluate and treat the problems that result. A penetrating wound may require surgery. Those with severe injuries or with a deteriorating level of consciousness may be kept hospitalized for observation. If there is bleeding inside the skull, the blood may need to be surgically drained; if a clot has formed, it may need to be removed. Severe skull fractures also require surgery. Supportive care and specific treatments may be required if the person experiences further complications. People who experience seizures, for example, may be given anticonvulsant drugs, and people who develop fluid on the brain (hydrocephalus ) may have a shunt inserted to drain the fluid.

In the event of long-term disability as a result of head injury, there are a variety of treatment programs available, including long-term rehabilitation, coma treatment centers, transitional living programs, behavior management programs, life-long residential or day treatment programs and independent living programs.

Prognosis

Prompt, proper diagnosis and treatment can help alleviate some of the problems that may develop after a head injury. However, it usually is difficult to predict the outcome of a brain injury in the first few hours or days; a person's prognosis may not be known for many months or even years.

The outlook for someone with a minor head injury generally is good, although recovery may be delayed, and symptoms such as headache, dizziness, and cognitive problems can persist for up to a year or longer after an accident. This can limit a person's ability to work and cause strain in personal relationships.

Serious head injuries can be devastating, producing permanent mental and physical disability. Epileptic seizures may occur after a severe head injury, especially a penetrating brain injury, a severe skull fracture, or a serious brain hemorrhage. Recovery from a severe head injury can be very slow, and it may take five years or longer to heal completely. Risk factors associated with an increased likelihood of memory problems or seizures after head injury include age, length and depth of coma, duration of post-traumatic and retrograde amnesia, presence of focal brain injuries, and initial Glasgow Coma Scale score.

KEY TERMS

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.

Electroencephalogram (EEG) A record of the tiny electrical impulses produced by the brain's activity picked up by electrodes placed on the scalp. By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain.

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.

Positron emission tomography (PET) A computerized diagnostic technique that uses radioactive substances to examine structures of the body. When used to assess the brain, it produces a three-dimensional image that shows anatomy and function, including such information as blood flow, oxygen consumption, glucose metabolism, and concentrations of various molecules in brain tissue.

As researchers learn more about the long-term effects of head injuries, they uncover links to later conditions. A 2003 report found that mild brain injury during childhood could speed up expression of schizophrenia in those who were already likely to get the disorder because of genetics. Those with a history of a childhood brain injury, even a minor one, were more likely to get familial schizophrenia than a sibling and to have earlier onset. Another study in 2003 found that people who had a history of a severe head injury were four times more likely to develop Parkinson's disease than the average population. Those requiring hospitalization for their head injuries were 11 times as likely. The risk did not increase for people receiving mild head injuries.

Prevention

Many severe head injuries could be prevented by wearing protective helmets during certain sports and when riding a bike or motorcycle. Seat belts and airbags can prevent many head injuries that result from car accidents. Appropriate protective headgear always should be worn on the job where head injuries are a possibility.

Parental concerns

Parents should insist that their children always use a seat belt when riding in a car. They should also insist that appropriate protective headgear always be worn when children engage in activities such as bicycling or rollerblading during which a head injury is possible. If a parent suspects a caregiver of abusing their child, prompt intervention is required.

Resources

BOOKS

Hergenroeder, Albert C., and Joseph N. Chorley. "Head and Neck Injuries." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 23134.

Hodge, Charles J. "Head Injury." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 22412.

Ropper, Allan H. "Traumatic Injuries of the Head and Spine." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 243441.

Saunders, Charles E., et al. Current Emergency Diagnosis and Treatment. New York: McGraw-Hill, 2003.

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.

Hrysomallis, C. "Impact energy attenuation of protective football headgear against a yielding surface." Journal of Science and Medicine in Sport 7, no. 2 (2004): 15664.

Stern, B., et al. "Profiles of patients with a history of mild head injury." International Journal of Neuroscience 114, no. 9 (2004): 122337.

Stocchetti, N., et al. "Inaccurate early assessment of neurological severity in head injury." Journal of Neurotrauma 21, no. 9 (2004): 113140.

ORGANIZATIONS

American Academy of Emergency Medicine. 611 East Wells Street, Milwaukee, WI 53202. Web site: <www.aaem.org/>.

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 College of Emergency Physicians. PO Box 619911, Dallas, TX 752619911. Web site: <www.acep.org/>.

American College of Sports Medicine. 401 W. Michigan St., Indianapolis, IN 462023233. Web site: <www.acsm.org/>.

International Brain Injury Association. 1150 South Washington St., Suite 210, Alexandria, VA 22314. Web site: <www.internationalbrain.org/>.

WEB SITES

Cyr, Dawna L., and Steven B. Johnson. "First Aid for Head Injuries." University of Maine Cooperative Extension. Available online at <www.cdc.gov/nasd/docs/d000801-d000900/d000815/d000815.html> (accessed January 6, 2005).

"Head and Brain Injuries." MedlinePlus. Available online at <www.nlm.nih.gov/medlineplus/headandbraininjuries.html> (accessed January 6, 2005).

"Head Injuries: What to Watch for Afterward." American Academy of Family Physicians. Available online at <http://familydoctor.org/x4958.xml> (accessed January 6, 2005).

"Head Injury." Institute for Neurology and Neurosurgery. Available online at <http://nyneurosurgery.org/head_intro.htm> (accessed January 6, 2005).

"The Management of Minor Closed Head Injury in Children (AC9858)." American Academy of Pediatrics. Available online at <www.aap.org/policy/ac9858.html> (accessed January 6, 2005).

L. Fleming Fallon, Jr., MD, DrPH

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Fallon, L.. "Head Injury." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 27 May. 2016 <http://www.encyclopedia.com>.

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Head Injury

Head Injury

Definition

Injury to the head may damage the scalp, skull or brain. The most important consequence of head trauma is traumatic brain injury. Head injury may occur either as a closed head injury, such as the head hitting a car's windshield, or as a penetrating head injury, as when a bullet pierces the skull. Both may cause damage that ranges from mild to profound. Very severe injury can be fatal because of profound brain damage.

Description

External trauma to the head is capable of damaging the brain, even if there is no external evidence of damage. More serious injuries can cause skull fracture, blood clots between the skull and the brain, or bruising and tearing of the brain tissue itself.

Injuries to the head can be caused by traffic accidents, sports injuries, falls, workplace accidents, assaults, or bullets. Most people have had some type of head injury at least once in their lives, but rarely do they require a hospital visit.

However, each year about two million people suffer from a more serious head injury, and up to 750,000 of them are severe enough to require hospitalization. Brain injury is most likely to occur in males between ages 15 and 24, usually as a result of car and motorcycle accidents. About 70% of all accidental deaths are due to head injuries, as are most of the disabilities that occur after trauma.

A person who has had a head injury and who is experiencing the following symptoms should seek medical care immediately:

  • serious bleeding from the head or face
  • loss of consciousness, however brief
  • confusion and lethargy
  • lack of pulse or breathing
  • clear fluid drainage from the nose or ear

Causes and symptoms

A head injury may cause damage both from the direct physical injury to the brain and from secondary factors, such as lack of oxygen, brain swelling, and disturbance of blood flow. Both closed and penetrating head injuries can cause swirling movements throughout the brain, tearing nerve fibers and causing widespread bleeding or a blood clot in or around the brain. Swelling may raise pressure within the skull (intracranial pressure) and may block the flow of oxygen to the brain.

Head trauma may cause a concussion, in which there is a brief loss of consciousness without visible structural damage to the brain. In addition to loss of consciousness, initial symptoms of brain injury may include:

  • memory loss and confusion
  • vomiting
  • dizziness
  • partial paralysis or numbness
  • shock
  • anxiety

After a head injury, there may be a period of impaired consciousness followed by a period of confusion and impaired memory with disorientation and a breakdown in the ability to store and retrieve new information. Others experience temporary amnesia following head injury that begins with memory loss over a period of weeks, months, or years before the injury (retrograde amnesia ). As the patient recovers, memory slowly returns. Post-traumatic amnesia refers to loss of memory for events during and after the accident.

Epilepsy occurs in 2-5% of those who have had a head injury; it is much more common in people who have had severe or penetrating injuries. Most cases of epilepsy appear right after the accident or within the first year, and become less likely with increased time following the accident.

Closed head injury

Closed head injury refers to brain injury without any penetrating injury to the brain. It may be the result of a direct blow to the head; of the moving head being rapidly stopped, such as when a person's head hits a windshield in a car accident; or by the sudden deceleration of the head without its striking another object. The kind of injury the brain receives in a closed head injury is determined by whether or not the head was unrestrained upon impact and the direction, force, and velocity of the blow. If the head is resting on impact, the maximum damage will be found at the impact site. A moving head will cause a "contrecoup injury" where the brain damage occurs on the side opposite the point of impact, as a result of the brain slamming into that side of the skull. A closed head injury also may occur without the head being struck, such as when a person experiences whiplash. This type of injury occurs because the brain is of a different density than the skull, and can be injured when delicate brain tissues hit against the rough, jagged inner surface of the skull.

Penetrating head injury

If the skull is fractured, bone fragments may be driven into the brain. Any object that penetrates the skull may implant foreign material and dirt into the brain, leading to an infection.

Skull fracture

A skull fracture is a medical emergency that must be treated promptly to prevent possible brain damage. Such an injury may be obvious if blood or bone fragments are visible, but it's possible for a fracture to have occurred without any apparent damage. A skull fracture should be suspected if there is:

  • blood or clear fluid leaking from the nose or ears
  • unequal pupil size
  • bruises or discoloration around the eyes or behind the ears
  • swelling or depression of part of the head

Intracranial hemorrhage

Bleeding (hemorrhage) inside the skull may accompany a head injury and cause additional damage to the brain. A blood clot (hematoma) may occur if a blood vessel between the skull and the brain ruptures; when the blood leaks out and forms a clot, it can press against brain tissue, causing symptoms from a few hours to a few weeks after the injury. If the clot is located between the bones of the skull and the covering of the brain (dura), it is called an epidural hematoma. If the clot is between the dura and the brain tissue itself, the condition is called a subdural hematoma. In other cases, bleeding may occur deeper inside the brain. This condition is called intracerebral hemorrhage or intracerebral contusion (from the word for bruising).

In any case, if the blood flow is not stopped, it can lead to unconsciousness and death. The symptoms of bleeding within the skull include:

  • nausea and vomiting
  • headache
  • loss of consciousness
  • unequal pupil size
  • lethargy

Postconcussion syndrome

If the head injury is mild, there may be no symptoms other than a slight headache. There also may be confusion, dizziness, and blurred vision. While the head injury may seem to have been quite mild, in many cases symptoms persist for days or weeks. Up to 60% of patients who sustain a mild brain injury continue to experience a range of symptoms called "postconcussion syndrome," as long as six months or a year after the injury.

The symptoms of postconcussion syndrome can result in a puzzling interplay of behavioral, cognitive, and emotional complaints that can be difficult to diagnose, including:

  • headache
  • dizziness
  • mental confusion
  • behavior changes
  • memory loss
  • cognitive deficits
  • depression
  • emotional outbursts

Diagnosis

The extent of damage in a severe head injury can be assessed with computed tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scans, electroencephalograms (EEG), and routine neurological and neuropsychological evaluations.

Doctors use the Glasgow Coma Scale to evaluate the extent of brain damage based on observing a patient's ability to open his or her eyes, respond verbally, and respond to stimulation by moving (motor response). Patients can score from three to 15 points on this scale. People who score below eight when they are admitted usually have suffered a severe brain injury and will need rehabilitative therapy as they recover. In general, higher scores on the Glasgow Coma Scale indicate less severe brain injury and a better prognosis for recovery.

Patients with a mild head injury who experience symptoms are advised to seek out the care of a specialist; unless a family physician is thoroughly familiar with medical literature in this newly emerging area, experts warn that there is a good chance that patient complaints after a mild head injury will be downplayed or dismissed. In the case of mild head injury or postconcussion syndrome, CT and MRI scans, electroencephalograms (EEG), and routine neurological evaluations all may be normal because the damage is so subtle. In many cases, these tests can't detect the microscopic damage that occurs when fibers are stretched in a mild, diffuse injury. In this type of injury, the axons lose some of their covering and become less efficient. This mild injury to the white matter reduces the quality of communication between different parts or the brain. A PET scan, which evaluates cerebral blood flow and brain metabolism, may be of help in diagnosing mild head injury.

Patients with continuing symptoms after a mild head injury should call a local chapter of a head-injury foundation that can refer patients to the best nearby expert.

Treatment

If a concussion, bleeding inside the skull, or skull fracture is suspected, the patient should be kept quiet in a darkened room, with head and shoulders raised slightly on pillow or blanket.

After initial emergency treatment, a team of specialists may be needed to evaluate and treat the problems that result. A penetrating wound may require surgery. Those with severe injuries or with a deteriorating level of consciousness may be kept hospitalized for observation. If there is bleeding inside the skull, the blood may need to be surgically drained; if a clot has formed, it may need to be removed. Severe skull fractures also require surgery. Supportive care and specific treatments may be required if the patient experiences further complications. People who experience seizures, for example, may be given anticonvulsant drugs, and people who develop fluid on the brain (hydrocephalus ) may have a shunt inserted to drain the fluid.

In the event of long-term disability as a result of head injury, there are a variety of treatment programs available, including long-term rehabilitation, coma treatment centers, transitional living programs, behavior management programs, life-long residential or day treatment programs and independent living programs.

Prognosis

Prompt, proper diagnosis and treatment can help alleviate some of the problems after a head injury. However, it usually is difficult to predict the outcome of a brain injury in the first few hours or days; a patient's prognosis may not be known for many months or even years.

The outlook for someone with a minor head injury generally is good, although recovery may be delayed and symptoms such as headache, dizziness, and cognitive problems can persist for up to a year or longer after an accident. This can limit a person's ability to work and cause strain in personal relationships.

Serious head injuries can be devastating, producing permanent mental and physical disability. Epileptic seizures may occur after a severe head injury, especially a penetrating brain injury, a severe skull fracture, or a serious brain hemorrhage. Recovery from a severe head injury can be very slow, and it may take five years or longer to heal completely. Risk factors associated with an increased likelihood of memory problems or seizures after head injury include age, length and depth of coma, duration of post-traumatic and retrograde amnesia, presence of focal brain injuries, and initial Glasgow Coma Scale score.

As researchers learn more about the long-term effects of head injuries, they have begun to uncover links to later conditions. A 2003 report found that mild brain injury during childhood could speed up expression of schizophrenia in those who were already likely to get the disorder because of genetics. Those with a history of a childhood brain injury, even a minor one, were more likely to get familial schizophrenia than a sibling and to have earlier onset. Another study in 2003 found that people who had a history of a severe head injury were four times more likely to develop Parkinson's disease than the average population. Those requiring hospitalization for their head injuries were 11 times as likely. The risk did not increase for people receiving mild head injuries.

Prevention

Many severe head injuries could be prevented by wearing protective helmets during certain sports, or when riding a bike or motorcycle. Seat belts and airbags can prevent many head injuries that result from car accidents. Appropriate protective headgear always should be worn on the job where head injuries are a possibility.

KEY TERMS

Computed tomography scan (CT) A diagnostic technique in which the combined use of a computer and x rays produce clear cross-sectional images of tissue. It provides clearer, more detailed information than x rays alone.

Electroencephalogram (EEG) A record of the tiny electrical impulses produced by the brain's activity. By measuring characteristic wave patterns, the EEG can help diagnose certain conditions of the brain.

Magnetic resonance imaging (MRI) A diagnostic technique that provides high quality cross-sectional images of organs within the body without x rays or other radiation.

Positron emission tomography (PET) scan A computerized diagnostic technique that uses radioactive substances to examine structures of the body. When used to assess the brain, it produces a three-dimensional image that reflects the metabolic and chemical activity of the brain.

Resources

PERIODICALS

"Childhood Head Injury Tied to Later Schizophreia." The Brown University Child and Adolescent Behavior Letter June 2003: 5.

"Link to Head Injury Found." Pain & Central Nervous System Week June 9, 2003: 3.

ORGANIZATIONS

American Epilepsy Society. 342 North Main Street, West Hartford, CT 06117-2507. (860) 586-7505. http://www.aesnet.org.

Brain Injury Association. 1776 Massachusetts Ave. NW, Ste. 100, Washington, DC 20036. (800) 444-6443.

Family Caregiver Alliance. 425 Bush St., Ste. 500, San Francisco, CA 94108. (800) 445-8106. http://www.caregiver.org.

Head Injury Hotline. PO Box 84151, Seattle WA 98124. (206) 621-8558. http://www.headinjury.com.

Head Trauma Support Project, Inc. 2500 Marconi Ave., Ste. 203, Sacramento, CA 95821. (916) 482-5770.

National Head Injury Foundation. 333 Turnpike Rd., Southboro, MA 01722. (617) 485-9950.

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Turkington, Carol; Odle, Teresa. "Head Injury." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. 27 May. 2016 <http://www.encyclopedia.com>.

Turkington, Carol; Odle, Teresa. "Head Injury." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. (May 27, 2016). http://www.encyclopedia.com/doc/1G2-3451600738.html

Turkington, Carol; Odle, Teresa. "Head Injury." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Retrieved May 27, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3451600738.html

Head Injury

HEAD INJURY

DEFINITION


Head injury refers to any damage to the scalp, skull, or brain. There are two general categories of head injuries: closed and penetrating. A closed head injury is one in which the skull is not broken open. For example, a boxer who receives a blow to the head may experience brain damage even though the skull is not damaged. This is a closed head injury. In a penetrating injury, the skull is broken open. For example, a bullet wound to the brain causes damage to the skull as well as to the brain. It is classified as a penetrating head injury. Both closed and penetrating head injuries can cause damage that ranges from mild to very serious. In the most severe cases, head injury can result in death.

DESCRIPTION


Head injuries can take many forms. These include skull fractures (broken bones in the skull), blood clots between the brain and the skull, and damage to the brain itself. Brain damage can occur even if the skull itself is undamaged. The brain may move around inside the skull with enough force to cause bruising and bleeding.

Most people have had some type of head injury at least once in their lives, but these events are usually not serious enough to require hospital care. However, about two million Americans experience serious head injuries every year. Up to 750,000 of these individuals require hospital treatment. Brain injuries are most likely to occur in males between the ages of fifteen and twenty-four. The most common causes of these injuries are car and motorcycle accidents. About 70 percent of all accidental deaths are due to head injuries, as are most disabilities resulting from accidents.

Head Injury: Words to Know

Computed tomography (CT) scan:
A diagnostic technique that uses X rays focused on a portion of the body from different directions to obtain a three-dimensional picture of that part of the body.
Computerized axial tomography (CAT) scan:
Another name for a computed tomography (CT) scan.
Electroencephalogram (EEG):
A record of the electrical impulses produced by the brain's activity as a way of measuring how the brain is working.
Magnetic resonance imaging (MRI):
A diagnostic technique for studying the structure of organs and tissues within the body without using radiation of any kind.
Positron emission tomography (PET):
A diagnostic technique that uses radioactive materials to study the structure and function of organs and tissues within the body.

CAUSES AND SYMPTOMS


The most common causes of head injuries are traffic accidents, sports injuries, falls, workplace accidents, assaults, and bullet wounds. The head may be damaged both from direct physical injury to the brain and from secondary factors. Secondary factors include lack of oxygen, swelling of the brain, and loss of blood flow to the brain. Both closed and penetrating head injuries can cause tearing of nerve tissue and widespread bleeding or a blood clot in the brain. Swelling may cause the brain to push against the skull, blocking the flow of blood and oxygen to the brain.

Trauma (sudden shock) to the head can cause a concussion (pronounced kun-KUH-shen). A concussion often causes loss of consciousness without visible damage to the skull. In addition to loss of consciousness, initial symptoms of brain injury include:

  • Memory loss and confusion
  • Vomiting
  • Dizziness
  • Partial paralysis or numbness
  • Shock
  • Anxiety

After a head injury, a person may experience a period when his or her brain does not function normally. The person may become confused, have partial memory loss, and lose the ability to learn normally. Other people experience amnesia (memory loss) that may last for a few weeks, months, or even years. As the patient recovers from the head injury, memory normally returns slowly.

A less common aftereffect of head injury is epilepsy (see epilepsy entry). Epilepsy is a seizure disorder characterized by shaking and loss of control over one's muscles. Epilepsy occurs as a result of 2 to 5 percent of all head injuries.

Closed Head Injury

Closed head injury is any head injury in which the skull is not broken open. A common cause of closed head injury is a direct blow to the head. Sudden starts and stops in a motor vehicle may also cause a closed head injury. In such cases, the brain is suddenly thrown with great force against the skull, causing damage to the brain.

Penetrating Head Injury

Penetrating head injuries occur when some object passes through the skull into the brain. The object itself may cause damage to the brain. A bullet wound to the head is an example. Pieces of the skull can also be pushed into the brain by the object. These pieces can damage the brain. An open wound to the brain may also lead to an infection that can cause further brain damage.

Skull Fracture

A skull fracture is an event in which one or more of the bones that make up the skull are broken. Skull fractures are serious accidents and require immediate medical attention. Some skull fractures are visible. Blood and bone fragments may be obvious. In some cases, however, there are no visible signs of a skull fracture. In such cases, other symptoms may indicate the possibility of a skull fracture. These include:

  • Blood or clear fluid leaking from the nose or ear
  • Pupils in the eyes having unequal sizes
  • Bruises or discoloration around the eyes or behind the ears
  • Swelling or a dent on any part of the head

Intracranial Hemorrhage

Bleeding inside the skull may accompany a head injury and may cause additional damage to the brain. A blood clot may also form between the brain and the skull. A blood clot is a mass of partly solidified blood that forms in the body. The clot can press against the brain and interrupt the flow of blood and oxygen through the brain. A reduced flow of oxygen prevents the brain from functioning normally.

COMPUTERIZED AXIAL TOMOGRAPHY

The discovery of X rays in the late 1890s changed the course of medicine. X rays gave doctors a way of seeing into a patient's body. Hard materials, like bone and teeth, show up clearly in an X-ray photograph.

But X-ray photographs have some serious disadvantages. They provide only a two-dimensional ("flat") view. They may not show cuts, breaks, lumps, and other disorders behind a bone or some other object. The problem is similar to trying to find out what the back of a person's head is like by looking at a photograph of his or her face.

In the 1960s, scientists found another way to use X rays that solved this problem. The technique is known as axial tomography. In axial tomography, X-ray photographs are taken of thin slices of an object. The X-ray camera is aimed at one part of the body, and a photograph taken. Then the camera is moved just slightly, and another photograph is taken. This process is repeated over and over again. Eventually, the researchers has a whole set of photographs of a part of the patient's body.

The problem is that it takes a long time to examine all these photographs and to see how they fit together. The obvious solution to that problem is to let a computer do the work. Today, the X-ray photographs can be fed into a computer, which assembles them into a three-dimensional photograph called a computerized axial tomography (CAT) scan or a computed tomography (CT) scan. The final product provides a much more detailed image of the body part being studied.

Bleeding can also occur deep within the brain. Wherever it occurs, bleeding in the brain is a very serious condition. It can lead to unconsciousness and death. The symptoms of bleeding within the brain include:

  • Nausea and vomiting
  • Headache
  • Loss of consciousness
  • Pupils in the eyes having unequal sizes
  • Listlessness

Postconcussion Syndrome

Mild head injuries usually produce symptoms such as headache, confusion, dizziness, and blurred vision. In some cases, these symptoms may last for a few days or weeks. Up to 60 percent of patients who sustain a head injury experience these symptoms for an even longer period of time. The symptoms can last as long as six months or a year after the injury. This condition is known as postconcussion syndrome.

Postconcussion syndrome is often difficult to diagnose. The symptoms include:

  • Headache
  • Dizziness
  • Mental confusion
  • Behavior changes
  • Memory loss
  • Loss of ability to think clearly
  • Depression
  • Sudden changes in mood

DIAGNOSIS


Some types of head injuries can be diagnosed based on the symptoms listed above. It is often difficult, however, to know how serious a head injury is. The fact that a person has a headache following a head injury, for example, does not really indicate how serious that injury is.

The extent of a head injury can be determined in a number of ways. The Glasgow Coma Scale is based on a patient's ability to open his or her eyes, give answers to questions, and respond to physical stimuli, such as a doctor's touch. A person can score anywhere from three to fifteen points on this scale. A score of less than eight points on the scale suggests the presence of serious brain damage.

Patients who are suspected of having severe brain damage should be referred to a medical specialist. The specialist will usually recommend a series of tests. The most common of these tests are the computed tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) scan, and electroencephalogram (EEG, pronounced ih-LEK-tro-in-SEH-fuh-lo-gram). These tests provide visual images of the brain and of the electrical activity taking place within the brain. They are often helpful in discovering damage to the brain.

Some forms of head injury are still difficult to diagnose, even with the best available tests. In such cases, the advice of experts in head injuries may be necessary for diagnosis and treatment.

TREATMENT


The first step in treating most forms of head injury is to keep the patient quiet in a darkened room. The patient's head and shoulders should be raised slightly on a pillow or blanket.

The next step in treatment depends on the nature of the injury. In the case of a penetrating wound, for example, surgery may be necessary. In a closed head injury, surgery may also be required to drain blood from the brain or to remove a clot. Surgery may also be needed to repair severe skull fractures.

Hospitalization is often necessary following head injuries. Medical workers will observe a patient to watch for any change in his or her condition. In addition, drugs can be given to prevent seizures. A tube can also be inserted into the brain to drain off excess fluid.

A person with a severe head injury may require long-term treatment. This treatment may be needed to help the person recover mental functions lost as a result of the injury. Long-term treatment can sometimes be conducted in day treatment programs. People with the most severe forms of head injury may need to be cared for in a special institution.

PROGNOSIS


The best hope for recovery from head injury is prompt diagnosis and treatment. However, the long-term prognosis for head injuries is often difficult to predict in the first few hours or days after an injury. In some cases, the prognosis is not known for months or years.

Individuals who experience mild head injuries often recover completely and fairly quickly. Some symptoms, however, may last for up to a year after the accident. These symptoms include headache, dizziness, and an inability to think clearly. These symptoms can obviously affect a person's ability to work and to deal normally with other people.

The prognosis for severe head injuries is not as good. Such injuries can often produce permanent physical or mental disabilities. Epileptic seizures are an example. Recovery from a severe head injury may take up to five years or more. The length of recovery often depends on a number of personal factors, such as a person's age, the length of time the person was unconscious following the injury, the number and location of brain injuries, and the duration of amnesia.

PREVENTION


Severe head injuries can often be prevented by some simple steps. People who take part in contact sports or ride bicycles or motorcycles, for example, should always wear helmets. Seat belts and airbags have prevented many head injuries in car accidents. People who work in dangerous occupations should also wear protective headgear on the job.

FOR MORE INFORMATION


Books

Stoller, Diane. Coping With Mild Traumatic Brain Injury. Garden City Park, NY: Avery Publishing Group, 1998.

Weiner, William J. Neurology for the Non-Neurologist, 3rd edition. Philadelphia: J. B. Lippincott, 1994.

Organizations

American Epilepsy Society. 638 Prospect Ave., Hartford, CT 06105. (203) 2324825.

Brain Injury Association. 1776 Massachusetts Ave., NW, Suite 100, Washington, DC 20036. (800) 4446443.

Head Injury Hotline. PO Box 84151, Seattle, WA 98124. (206) 6218558.

Head Trauma Support Project, Inc. 2500 Marconi Ave., Suite 203, Sacramento, CA 95821. (916) 4825770.

National Head Injury Foundation. 333 Turnpike Rd., Southboro, MA 01722. (617) 4859950.

Web sites

"Ask NOAH About: Spinal Cord and Head Injuries." NOAH: New York Online Access to Health. [Online] http://www.noah.cuny.edu/neuro/spinal.html (accessed on October 21, 1999).

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head injury

head injury (in-jeri) n. an injury usually resulting from a blow to the head and often associated with brain injury. It may result in contusion or – if the blood vessels in the head are torn – a haematoma. The level of consciousness of a patient following a head injury can be monitored using the Glasgow scoring system.

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