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 2–5 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. 2313–4.

Hodge, Charles J. "Head Injury." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 2241–2.

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. 2434–41.

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): 1662–6.

Hrysomallis, C. "Impact energy attenuation of protective football headgear against a yielding surface." Journal of Science and Medicine in Sport 7, no. 2 (2004): 156–64.

Stern, B., et al. "Profiles of patients with a history of mild head injury." International Journal of Neuroscience 114, no. 9 (2004): 1223–37.

Stocchetti, N., et al. "Inaccurate early assessment of neurological severity in head injury." Journal of Neurotrauma 21, no. 9 (2004): 1131–40.

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 60007–1098. Web site: <www.aap.org/>.

American College of Emergency Physicians. PO Box 619911, Dallas, TX 75261–9911. Web site: <www.acep.org/>.

American College of Sports Medicine. 401 W. Michigan St., Indianapolis, IN 46202–3233. 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

Head Injury

Definition

Injury to the head may damage the scalp, skull, or brain. The most important consequence of head injury 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 such 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.

Each year, approximately two million people suffer from a serious head injury. 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 immediate medical care:

• 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 may experience temporary (retrograde) amnesia following head injury. As a person recovers, memory slowly returns. Post-traumatic amnesia refers to loss of memory for events during and after an accident.

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

Closed head injury

Closed head injury refers to brain trauma without any penetrating injury to the brain. It may be the result of a direct blow to the head, of a moving head being rapidly stopped, or by a sudden deceleration of the head without 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 a head was resting on impact, the maximum damage will be found at the impact site. A moving head will cause a contrecoup injury in which 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, 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. It is possible for a fracture to have occurred without any apparent damage. A skull fracture should be suspected if any of the following are observed:

• blood or clear fluid leaking from 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 that may arise within 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.

If the blood flow within the skull is not stopped, it can lead to unconsciousness and death. The signs and symptoms of bleeding within the skull include:

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

Post-concussion syndrome

If a head injury is mild, there may be no symptoms other than a slight headache, or 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 persons who sustain a mild brain injury continue to experience a range of symptoms called post-concussion syndrome, for 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) scan, electroencephalograms (EEG), and routine neurological and neuropsychological evaluations.

Physicians 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). Persons 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.

Persons 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 a complaint 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 may all 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 which the axons in the brain lose some of their covering and become less efficient. This mild injury to the white matter reduces the quality of communication between different parts and the brain. A PET scan, which evaluates cerebral blood flow and brain metabolism, may be of help in diagnosing mild head injury, although many experts still considered this to be an experimental procedure.

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

Treatment

If a concussion, bleeding inside the skull, or skull fracture is suspected, a 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 any problems that result. A penetrating wound may require surgery. Those individuals 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 a 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 that occurs as a result of head injury, a variety of treatment programs are 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 diagnosis and treatment can help alleviate some of the problems after a head injury. However, it is usually 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 is generally 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.

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 may take five years or longer to completely heal. 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.

Health care team roles

First aid may be given by emergency medical technicians. Physicians trained in emergency medicine often provide initial care in a hospital. Neurosurgeons and neurologists may be asked to assist with care. Rehabilitation specialists such as physicians, physical therapists, speech therapists, or occupational therapists may provide rehabilitation. Nurses provide supportive care throughout, including 24-hour care, home nursing care, and patient education.

Prevention

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

KEY TERMS

Amnesia— Loss of memory.

Computed tomography (CT) scan— A diagnostic technique in which the combined use of a computer and x rays produce clear cross-sectional images of tissue.

Contrecoup injury— Brain damage occurring on the side opposite to the point of impact.

Contusion— Bruise.

Electroencephalogram (EEG)— A record of the tiny electrical impulses produced by the brain's activity.

Hematoma— Blood clot.

Hemorrhage— Heavy or uncontrolled bleeding.

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

Positron emission tomography (PET) scan— A computerized diagnostic technique that uses radioactive substances to examine structures of the body.

Post-traumatic amnesia— Loss of memory for events during and after an accident.

Retrograde amnesia— Memory loss for events in the past that occurs over a period of time.

Resources

BOOKS

Adams, Raymond D., Maurice Victor, and Allan H. Ropper. Adams and Victor's Principles of Neurology, 6th ed. New York: McGraw Hill, 1997.

Bailes, Julian E., Mark R. Lovell, and Joseph C. Maroon. Sports Related Concussion. St. Louis, MO: Quality Medical Publishing, 1998.

Parker, Rolland S. Concussive Brain Trauma: Neurobehavioral Impairment and Maladaptation. Boca Raton, FL: Lewis Publishers, 2000.

Rizzo, Matthew, and Daniel Tranel. Head Injury and Postconcussive Syndrome. London: Churchill Livingstone, 1996.

Wrightston, Philip, and D. M. A. Gronwall. Mild Head Injury: A Guide to Management. New York: Oxford, 1999.

PERIODICALS

Bailes, J. E., and R. C. Cantu. "Head Injury in Athletes." Neurosurgery 48, no. 1 (2001): 26-45.

Centers for Disease Control and Injury. "Facts about Concussion and Brain Injury and Where to Get Help." 〈http://webapp.cdc.gov/IXPRESS/PUBSPROD/NCIPC+BOOK/NCIPC.DML〉.

Guskiewicz, K. M., N. L. Weaver, D. A. Padua, and W. E. Garrett. "Epidemiology of Concussion in Collegiate and High School Football Players." American Journal of Sports Medicine 28, no. 5 (2000): 643-50.

Maroon, J. C., et al. "Cerebral Concussion in Athletes: Evaluation and Neuropsychological Testing." Neurosurgery 47, no. 3 (2000): 659-69.

Proctor, M. R., and R. C. Cantu. "Head and Neck Injuries in Young Athletes." Clinics in Sports Medicine 19, no. 4 (2000): 693-715.

Reece, R. M., and R. Sege. "Childhood Head Injuries: Accidental or Inflicted?" Archives of Pediatric and Adolescent Medicine 154, no. 1 (2000): 11-15.

ORGANIZATIONS

American Academy of Neurology. 1080 Montreal Avenue, St. Paul, MN 55116. (651) 695-1940. (651) 695-2791. 〈http://www.aan.com/〉. info@aan.org.

American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. (847) 434-4000. (847) 434-8000. 〈http://www.aap.org/default.htm〉. kidsdoc@aap.org.

American College of Emergency Physicians. P.O. Box 619911, Dallas, TX 75261-9911. (800) 798-1822. (972) 550-0911. (972) 580-2816. 〈http://www.acep.org/〉. info@acep.org.

American College of Osteopathic Emergency Physicians. 142 E. Ontario Street, Suite 550, Chicago, IL 60611. (312) 587-3709. (800) 521-3709. (312) 587-9951. 〈http://www.acoep.org〉.

Brain Injury Association. 105 North Alfred Street, Alexandria, VA 22314. (800) 444-6443. (703) 236-6000. (703) 236-6001. 〈http://www.biausa.org/Sportsfs.htm〉. prevention@biausa.org.

Emergency Nurses Association. 915 Lee Street, Des Plaines, IL 60016-6569. (800) 900-9659. (847) 460-4001. 〈http://www.ena.org/about/index.htm〉.

International Brain Injury Association. 1150 South Washington Street, Suite 210, Alexandria, VA 22314. (703) 683-8400. (703) 683-8996. 〈http://www.internationalbrain.org/〉. info@internationalbrain.org.

National Center for Injury Prevention and Control. Centers for Disease Control and Prevention, Mailstop F41, 4770 Buford Highway NE, Atlanta, GA 30341-3724. (770) 488-4031. (770) 488-4338. 〈http://www.cdc.gov/ncipc/dacrrdp/tbi.htm〉. dardinfo@cdc.gov.

OTHER

American Academy of Family Physicians. 〈http://familydoctor.org/handouts/458.html〉.

American Academy of Pediatrics. 〈http://www.aap.org/policy/ac9858.html〉.

Brain Injury Association. 〈http://www.biausa.org/〉.

Glasgow Coma Score. 〈http://www.trauma.org/scores/gcs.html〉.

Head Injury Association of Waterloo-Wellington, Canada. 〈http://www.ahs.uwaterloo.ca/∼cahr/headfall.html〉.

Head Injury Hotline. 〈http://www.headinjury.com/faqpcs.htm〉.

Pashby Sport Concussion Safety Website. 〈http://www.concussionsafety.com/〉.

University of California Los Angeles. 〈http://neurosurgery.ucla.edu/Diagnoses/BrainInjury/BrainInjuryDis_6.html〉.

University of Missouri Health Center. 〈http://www.muhealth.org/∼neuromedicine/concussion.shtml〉.

Head injury

Definition

Injury to the head may damage the scalp, skull , or brain . The most important consequence of head injury 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 such 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.

Each year, approximately two million people suffer from a serious head injury. 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 immediate medical care:

• 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 may experience temporary (retrograde) amnesia following head injury. As a person recovers, memory slowly returns. Post-traumatic amnesia refers to loss of memory for events during and after an accident.

Epilepsy occurs in 2–5% of those who have experienced a head injury. It is much more common in people who have had severe or penetrating injuries. Most cases of epilepsy appear immediately after an accident or within the first year. They become less likely with increased time following an accident.

Closed head injury

Closed head injury refers to brain trauma without any penetrating injury to the brain. It may be the result of a direct blow to the head, of a moving head being rapidly stopped, or by a sudden deceleration of the head without 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 a head was resting on impact, the maximum damage will be found at the impact site. A moving head will cause a contrecoup injury in which 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 , 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. It is possible for a fracture to have occurred without any apparent damage. A skull fracture should be suspected if any of the following are observed:

• blood or clear fluid leaking from nose or ears
• unequal pupil size
• bruises or discoloration around the eyes or behind the ears
• swelling or depression of the 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 that may arise within 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.

If the blood flow within the skull is not stopped, it can lead to unconsciousness and death. The signs and symptoms of bleeding within the skull include:

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

Post-concussion syndrome

If a head injury is mild, there may be no symptoms other than a slight headache, or 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 persons who sustain a mild brain injury continue to experience a range of symptoms called post-concussion syndrome, for 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 diag nose, including:

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

KEY TERMS

Amnesia —Loss of memory.

Computed tomography (CT) scan —A diagnostic technique in which the combined use of a computer and x rays produce clear cross-sectional images of tissue.

Contrecoup injury —Brain damage occurring on the side opposite to the point of impact.

Contusion —Bruise.

Electroencephalogram (EEG) —A record of the tiny electrical impulses produced by the brain's activity.

Hematoma —Blood clot.

Hemorrhage —Heavy or uncontrolled bleeding.

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

Positron emission tomography (PET) scan —A computerized diagnostic technique that uses radioactive substances to examine structures of the body.

Post-traumatic amnesia —Loss of memory for events during and after an accident.

Retrograde amnesia —Memory loss for events in the past that occurs over a period of time.

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 ) scan, electroencephalograms (EEG), and routine neurological and neuropsychological evaluations.

Physicians 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). Persons 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.

Persons 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 a complaint 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 may all 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 which the axons in the brain lose some of their covering and become less efficient. This mild injury to the white matter reduces the quality of communication between different parts and the brain. A PET scan, which evaluates cerebral blood flow and brain metabolism , may be of help in diagnosing mild head injury, although many experts still considered this to be an experimental procedure.

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

Treatment

If a concussion, bleeding inside the skull, or skull fracture is suspected, a 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 any problems that result. A penetrating wound may require surgery. Those individuals 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 a 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 that occurs as a result of head injury, a variety of treatment programs are 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 diagnosis and treatment can help alleviate some of the problems after a head injury. However, it is usually 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 is generally 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.

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 may take five years or longer to completely heal. 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.

Health care team roles

First aid may be given by emergency medical technicians . Physicians trained in emergency medicine often provide initial care in a hospital. Neurosurgeons and neurologists may be asked to assist with care. Rehabilitation specialists such as physicians, physical therapists, speech therapists, or occupational therapists may provide rehabilitation. Nurses provide supportive care throughout, including 24-hour care, home nursing care, and patient education .

Prevention

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

Resources

BOOKS

Adams, Raymond D., Maurice Victor, and Allan H. Ropper. Adam's and Victor's Principles of Neurology, 6th ed. New York: McGraw Hill, 1997.

Bailes, Julian E., Mark R. Lovell, and Joseph C. Maroon. Sports Related Concussion. St. Louis: Quality Medical Publishing, 1998.

Parker, Rolland S. Concussive Brain Trauma: Neurobehavioral Impairment and Maladaptation. Boca Raton, FL: Lewis Publishers, 2000.

Rizzo, Matthew, and Daniel Tranel. Head Injury and Postconcussive Syndrome. London: Churchill Livingstone, 1996.

Wrightston, Philip, and D. M. A. Gronwall. Mild Head Injury: A Guide to Management. New York: Oxford, 1999.

PERIODICALS

Bailes, J. E., and R. C. Cantu. "Head Injury in Athletes." Neurosurgery 48, no. 1 (2001): 26-45.

Centers for Disease Control and Injury. "Facts about Concussion and Brain Injury and Where to Get Help." <http://webapp.cdc.gov/IXPRESS/PUBSPROD/NCIPC+BOOK/NCIPC.DML>.

Guskiewicz, K. M., N. L. Weaver, D. A. Padua, and W. E. Garrett. "Epidemiology of Concussion in Collegiate and High School Football Players." American Journal of Sports Medicine 28, no. 5 (2000): 643-50.

Maroon, J. C., et al. "Cerebral Concussion in Athletes: Evaluation and Neuropsychological Testing." Neurosurgery 47, no. 3 (2000): 659-69.

Proctor, M. R., and R. C. Cantu. "Head and Neck Injuries in Young Athletes." Clinics in Sports Medicine 19, no. 4(2000): 693-715.

Reece, R. M., and R. Sege. "Childhood Head Injuries: Accidental or Inflicted?" Archives of Pediatric and Adolescent Medicine 154, no. 1 (2000): 11-15.

ORGANIZATIONS

American Academy of Neurology. 1080 Montreal Avenue, St. Paul, Minnesota 55116. (651) 695-1940. (651) 695-2791. <http://www.aan.com/>. info@aan.org.

American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. (847) 434-4000. (847) 434-8000. <http://www.aap.org/default.htm>. kidsdoc@aap.org.

American College of Emergency Physicians. P.O. Box 619911, Dallas, TX 75261-9911. (800) 798-1822. (972) 550-0911. (972) 580-2816. <http://www.acep.org/>. info@acep.org.

American College of Osteopathic Emergency Physicians. 142 E. Ontario Street, Suite 550, Chicago, IL 60611. (312) 587-3709. (800) 521-3709. (312) 587-9951. <http://www.acoep.org>.

Brain Injury Association. 105 North Alfred Street, Alexandria, VA 22314. (800) 444-6443. (703) 236-6000. (703) 236-6001. <http://www.biausa.org/Sportsfs.htm>. prevention@biausa.org.

Emergency Nurses Association. 915 Lee Street, Des Plaines, IL 60016-6569. (800) 900-9659. (847) 460-4001. <http://www.ena.org/about/index.htm>.

International Brain Injury Association. 1150 South Washington Street, Suite 210, Alexandria, VA 22314.(703) 683-8400. (703) 683-8996. <http://www.internationalbrain.org/>. info@internationalbrain.org.

National Center for Injury Prevention and Control. Centers for Disease Control and Prevention, Mailstop F41, 4770 Buford Highway NE, Atlanta, GA 30341-3724. (770) 488-4031. (770) 488-4338. <http://www.cdc.gov/ncipc/dacrrdp/tbi.htm>. dardinfo@cdc.gov.

OTHER

American Academy of Family Physicians. <http://familydoctor.org/handouts/458.html>.

American Academy of Pediatrics. <http://www.aap.org/policy/ac9858.html>.

Brain Injury Association. <http://www.biausa.org/>.

Glasgow Coma Score. <http://www.trauma.org/scores/gcs.html>.

Head Injury Association of Waterloo-Wellington, Canada. <http://www.ahs.uwaterloo.ca/~cahr/headfall.html>.

Head Injury Hotline. <http://www.headinjury.com/faqpcs.htm>.

Pashby Sport Concussion Safety Website. <http://www.concussionsafety.com/>.

University of California Los Angles. <http://neurosurgery.ucla.edu/Diagnoses/BrainInjury/BrainInjuryDis_6.html>.

University of Missouri Health Center. <http://www.muhealth.org/~neuromedicine/concussion.shtml>.

L. Fleming Fallon, Jr., M.D., Dr.P.H.

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.

Head injury

Definition

Injury to the head may damage the scalp, skull, or brain. The most important consequence of head injury 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 such 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.

Each year, approximately two million people suffer from a serious head injury. 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 immediate medical care:

• 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 may experience temporary (retrograde) amnesia following head injury. As a person recovers, memory slowly returns. Post-traumatic amnesia refers to loss of memory for events during and after an accident.

Epilepsy occurs in 2–5% of those who have experienced a head injury. It is much more common in people who have had severe or penetrating injuries. Most cases of epilepsy appear immediately after an accident or within the first year. They become less likely with increased time following an accident.

Closed head injury

Closed head injury refers to brain trauma without any penetrating injury to the brain. It may be the result of a direct blow to the head, of a moving head being rapidly stopped, or by a sudden deceleration of the head without 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 a head was resting on impact, the maximum damage will be found at the impact site. A moving head will cause a contrecoup injury in which 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, 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. It is possible for a fracture to have occurred without any apparent damage. A skull fracture should be suspected if any of the following are observed:

• blood or clear fluid leaking from 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 that may arise within 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.

If the blood flow within the skull is not stopped, it can lead to unconsciousness and death . The signs and symptoms of bleeding within the skull include:

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

Post-concussion syndrome

If a head injury is mild, there may be no symptoms other than a slight headache, or 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 persons who sustain a mild brain injury continue to experience a range of symptoms called post-concussion syndrome, for 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) scan, electroencephalograms (EEG), and routine neurological and neuropsychological evaluations.

Physicians 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). Persons 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.

Persons 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 a complaint after a mild head injury will be downplayed or dismissed. In the case of mild head injury or post-concussion syndrome, CT and MRI scans, electroencephalograms (EEG), and routine neurological evaluations may all 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 which the axons in the brain lose some of their covering and become less efficient. This mild injury to the white matter reduces the quality of communication between different parts and the brain. A PET scan, which evaluates cerebral blood flow and brain metabolism, may be of help in diagnosing mild head injury, although many experts still considered this to be an experimental procedure.

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

Treatment

If a concussion, bleeding inside the skull, or skull fracture is suspected, a 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 any problems that result. A penetrating wound may require surgery. Those individuals 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 a 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 that occurs as a result of head injury, a variety of treatment programs are 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 diagnosis and treatment can help alleviate some of the problems after a head injury. However, it is usually 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 is generally 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.

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 may take five years or longer to completely heal. 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.

Caregiver concerns

First aid may be given by emergency medical technicians. Physicians trained in emergency medicine often provide initial care in a hospital. Neurosurgeons and neurologists may be asked to assist with care. Rehabilitation specialists such as physicians, physical therapists, speech therapists, or occupational therapists may provide rehabilitation. Nurses provide supportive care throughout, including 24-hour care, home nursing care, and patient education .

KEY TERMS

Amnesia —Loss of memory.

Contrecoup injury —Brain damage occurring on the side opposite to the point of impact.

Electroencephalogram (EEG) —A record of the tiny electrical impulses produced by the brain's activity.

Hematoma —Blood clot.

Hemorrhage —Heavy or uncontrolled bleeding.

Positron emission tomography (PET) scan —A computerized diagnostic technique that uses radioactive substances to examine structures of the body.

Post-traumatic amnesia —Loss of memory for events during and after an accident.

Retrograde amnesia —Memory loss for events in the past that occurs over a period of time.

Prevention

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

Resources

BOOKS

Adams, Raymond D., Maurice Victor, and Allan H. Ropper. Adams and Victor's Principles of Neurology, 6th ed. New York: McGraw Hill, 1997.

Bailes, Julian E., Mark R. Lovell, and Joseph C. Maroon. Sports Related Concussion. St. Louis, MO: Quality Medical Publishing, 1998.

Parker, Rolland S. Concussive Brain Trauma: Neurobehavioral Impairment and Maladaptation. Boca Raton, FL: Lewis Publishers, 2000.

Rizzo, Matthew, and Daniel Tranel. Head Injury and Postconcussive Syndrome. London: Churchill Living-stone, 1996.

Wrightston, Philip, and D. M. A. Gronwall. Mild Head Injury: A Guide to Management. New York: Oxford, 1999.

PERIODICALS

Bailes, J. E., and R. C. Cantu. “Head Injury in Athletes.” Neurosurgery 48, no. 1 (2001): 26–45.

Centers for Disease Control and Injury. “Facts about Concussion and Brain Injury and Where to Get Help.” http://webapp.cdc.gov/IXPRESS/PUBSPROD/NCIPC+BOOK/NCIPC.DML.

Guskiewicz, K. M., N. L. Weaver, D. A. Padua, and W. E. Garrett. “Epidemiology of Concussion in Collegiate and High School Football Players.” American Journal of Sports Medicine 28, no. 5 (2000): 643–50.

Maroon, J. C., et al. “Cerebral Concussion in Athletes: Evaluation and Neuropsychological Testing.” Neuro-surgery 47, no. 3 (2000): 659–69.

Proctor, M. R., and R. C. Cantu. “Head and Neck Injuries in Young Athletes.” Clinics in Sports Medicine 19, no. 4 (2000): 693–715.

Reece, R. M., and R. Sege. “Childhood Head Injuries: Accidental or Inflicted?” Archives of Pediatric and Adolescent Medicine 154, no. 1 (2000): 11–15.

ORGANIZATIONS

American Academy of Neurology. 1080 Montreal Avenue, St. Paul, MN 55116. (651) 695-1940. (651) 695-2791. http://www.aan.com/.info@aan.org.

American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. (847) 434-4000. (847) 434-8000. http://www.aap.org/default.htm.kidsdoc@aap.org.

AmericanCollege ofEmergency Physicians. P.O. Box 619911, Dallas, TX 75261-9911. (800) 798-1822. (972) 550-0911. (972) 580-2816. http://www.acep.org/.info@acep.org.

American College of Osteopathic Emergency Physicians. 142 E. Ontario Street, Suite 550, Chicago, IL 60611. (312) 587-3709. (800) 521-3709. (312) 587-9951. http://www.acoep.org.

Brain Injury Association. 105 North Alfred Street, Alexandria, VA 22314. (800) 444-6443. (703) 236-6000. (703) 236-6001. http://www.biausa.org/Sportsfs.htm.prevention@biausa.org.

Emergency Nurses Association. 915 Lee Street, Des Plaines, IL 60016-6569. (800) 900-9659. (847) 460-4001. http://www.ena.org/about/index.htm.

International Brain Injury Association. 1150 South Washington Street, Suite 210, Alexandria, VA 22314. (703) 683-8400. (703) 683-8996. http://www.internationalbrain.org/.info@internationalbrain.org.

National Center for Injury Prevention and Control. Centers for Disease Control and Prevention, Mailstop F41, 4770 Buford Highway NE, Atlanta, GA 30341-3724. (770) 488-4031. (770) 488-4338. http://www.cdc.gov/ncipc/dacrrdp/tbi.htm.dardinfo@cdc.gov.

OTHER

American Academy of Family Physicians. http://familydoctor.org/handouts/458.html.

American Academy of Pediatrics. http://www.aap.org/policy/ac9858.html.

Brain Injury Association. http://www.biausa.org/.

Glasgow Coma Score. http://www.trauma.org/scores/gcs.html.

Head Injury Association of Waterloo-Wellington, Canada. http://www.ahs.uwaterloo.ca/̃cahr/headfall.html.

Head Injury Hotline. http://www.headinjury.com/faqpcs.htm.

Pashby Sport Concussion Safety Website. http://www.concussionsafety.com/.

University of California Los Angeles. http://neurosurgery.ucla.edu/Diagnoses/BrainInjury/BrainInjuryDis_6.html.

University of Missouri Health Center. http://www.muhealth.org/̃neuromedicine/concussion.shtml.

L. Fleming Fallon Jr., M.D., Dr.P.H.