A subdural hematoma is a collection of blood in the space between the outer 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 brain covering after ablow to the head.
A subdural hematoma most often affects people who are prone to falling. Onlya slight bump 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 that seeps out can be slowly absorbed over several weeks. Larger hematomas, like a big bruise, can gradually enlarge over several weeks even after the bleeding has stopped. This enlargement can compress the brain itself, and may lead to death if the blood isn't removed.
The time between the injury and the appearance of symptoms can vary from lessthan 48 hours to several weeks or more. Symptoms that appear in less than 48hours indicate a serious subdural hematoma which may be fatal. However, if symptoms don't appear until at least two weeks after the accident, the condition is not so serious. The very young and the elderly are most likely to experience this type of chronic condition, which is less risky. Prompt medical care can reduce the probability of permanent brain damage in these cases.
Symptoms (which may come and go) include:
- Episodes ofconfusion and drowsiness
- One-sided weakness or paralysis
- Enlarged pupils
- Two different sizes of pupils
- Convulsions or loss of consciousness
A doctor should be contacted immediately if symptoms appear. Because these symptoms mimic the signs of a stroke, the patient should tell the doctor aboutany head injury within the previous few months. In an infant, symptoms may include increased pressure within the skull, growing head size, bulging soft spots on an infant's skull), vomiting, irritability, lethargy, and seizures.
A chronic subdural hematoma can be difficult to diagnose, but a slow loss ofconsciousness after a head injury is assumed to be a hematoma unless proven otherwise. The hematoma can be confirmed with magnetic resonance imaging (MRI)(a hematoma can be hard to see on a computed tomography scan (CT scan), depending on how long after the hemorrhage the scan is done).
If the hematoma is small and doesn't cause symptoms, no treatment is necessary. In more serious cases, hematomas may need to be surgically removed. The accumulated liquid blood can be drained from holes drilled into the skull. Thesurgeon may need to open a section of skull to remove a large hematoma or totie off a bleeding vein.
Corticosteroids and diuretics (water pills) can control brain swelling. Aftersurgery, antiseizure drugs may help control or prevent seizures, which may start as long as two years after the head injury.
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 muchfaster.