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) 232–4825.

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

Head Injury Hotline. PO Box 84151, Seattle, WA 98124. (206) 621–8558.

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

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

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).