|
Definition A subdural hematoma is a collection of blood in the space between the outer layer (dura) and middle layers of the covering of the brain (the meninges). It is most often caused by torn, bleeding veins on the inside of the dura as a result of a blow to the head. Description Subdural hematomas most often affect people who are prone to falling. Only a slight hit on the head or even a fall to the ground without hitting the head may be enough to tear veins in the brain, often without fracturing the skull. There may be no external evidence of the bruising on the brain's surface. Small subdural hematomas may not be very serious, and the blood can be slowly absorbed over several weeks. Larger hematomas, however, can gradually enlarge over several weeks, even though the bleeding has stopped. This enlargement can compress the brain itself, possibly leading to death if the blood is not drained. The time between the injury and the appearance of symptoms can vary from less than 48 hours to several weeks, or more. Symptoms appearing in less than 48 hours are due to an acute subdural hematoma. This type of bleeding is often fatal, and results from tearing of the venous sinus. If more than two weeks have passed before symptoms appear, the condition is called a chronic subdural hematoma, resulting from tearing of the smaller vein. The young and the old are most likely to experience a chronic condition. This chronic form is less risky, as pressure of the veins against the skull lessens the bleeding. Prompt medical care can reduce the probability of permanent brain damage. Causes and symptoms A subdural hematoma is caused by an injury to the head that tears blood vessels. In childhood, hematomas are a common complication of falls. A subdural hematoma also may be an indication of child abuse, as evidenced by shaken baby syndrome. Symptoms tend to fluctuate, and include: - headache
- episodes of confusion and drowsiness
- one-sided weakness or paralysis
- lethargy
- enlarged or asymmetric pupils
- convulsions or loss of consciousness after head injury
- coma
A doctor should be contacted immediately if symptoms appear. Because these symptoms mimic the signs of a stroke, the patient should tell the doctor about any head injury within the previous few months. In an infant, symptoms may include increased pressure within the skull, growing head size, bulging fontanelle (one of two soft spots on a infant's skull), vomiting, irritability, lethargy, and seizures. In cases of child abuse, there may be fractures of the skull or other bones. Diagnosis A chronic subdural hematoma can be difficult to diagnose, but a slow loss of consciousness after a head injury is assumed to be a hematoma unless proven otherwise. The hematoma can be confirmed with magnetic resonance imaging (MRI), which is the preferred type of scan; a hematoma can be hard to detect on a computed tomography scan (CT scan), depending on how long after the hemorrhage the CT is done. Treatment Small hematomas that do not cause symptoms may not need to be treated. Otherwise, the hematoma should be surgically removed. Liquid blood can be drained from burr holes drilled into the skull. The surgeon may have to open a section of skull to remove a large hematoma or to tie off the bleeding vein. Corticosteroids and diuretics can control brain swelling. After surgery, anticonvulsant drugs (such as phenytoin) may help control or prevent seizures, which can begin as late as two years after the head injury. Prognosis If treatment is provided soon enough, recovery is usually complete. Headache, amnesia, attention problems, anxiety, and giddiness may continue for some time after surgery. Most symptoms in adults usually disappear within six months, with further improvement over several years. Children tend to recover much faster. Prevention Because a subdural hematoma usually follows a head injury, preventing head injury can prevent a hematoma. - Corticosteroids
- A group of drugs similar to natural corticosteroid hormones produced by the adrenal glands. The drugs have a wide variety of applications, including use for inflammatory disorders and swelling.
- Diuretics
- A group of drugs that helps remove excess water from the body by increasing the amount lost by urination.
- Fontanelle
- One of the two soft areas on a baby's scalp; a membrane-covered gap between the bones of the skull.
For Your Information Books - Brumback, Roger A. Neurology and Clinical Neuroscience. New York: Springer-Verlag, 1993.
- Lambert, David, Martyn Bramwell, and Gail Lawther, eds. The Brain: A User's Manual. New York: Springer-Verlag, 1993.
Organizations- American Academy of Neurology. 1080 Montreal Ave., St. Paul, MN 55116. (612) 695-1940. http://www.aan.com
- Brain Injury Association of America. 105 North Alfred St., Alexandria, VA 22314. (800) 444-6443. http://www.biausa.org
- Head Injury Hotline. P.O. Box 84151, Seattle WA 98124. (206) 621- 8558.
- Head Trauma Support Project, Inc. 2500 Marconi Ave., Ste. 203, Sacramento, CA 95821. (916) 482-5770.
Source: Gale Encyclopedia of Medicine, Published December, 2002 by the Gale Group
The Essay Author is Carol A. Turkington.
Return to the previous page
|
