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A chronic subdural hematoma (SDH) is a collection of blood on the brain’s surface, under the outer covering of the brain (dura).
It usually begins forming several days or weeks after bleeding initially starts. Bleeding is usually due to a head injury.
A chronic SDH doesn’t always produce symptoms. When it does, it generally requires surgical treatment.
Major or minor trauma to the brain from a head injury is the most common cause of a chronic SDH. In rare cases, one may form due to unknown reasons, unrelated to injury.
The bleeding that leads to a chronic SDH occurs in the small veins located between the brain’s surface and dura. When they break, blood leaks over a long period of time and forms a clot. The clot puts increasing pressure on your brain.
If you’re 60 or older, you have a higher risk for this type of hematoma. Brain tissue shrinks as part of the normal aging process. Shrinking weakens veins, so even a minor head injury may cause a chronic SDH.
Heavy drinking for several years is another factor that increases your risk for chronic SDH. Other factors include using blood-thinning medications, aspirin, and anti-inflammatory medications for a long period of time.
Symptoms of this condition include:
The exact symptoms that appear depend on the location and size of your hematoma. Some symptoms occur more often than others. Up to 80 percent of people with this type of hematoma have headaches.
If your clot is large, loss of the ability to move (paralysis) can occur. You might also become unconscious and slip into a coma. A chronic SDH that puts severe pressure on the brain can cause permanent brain damage and even death.
If you or someone you know exhibits symptoms of this condition, it’s important to seek prompt medical help. People who have seizures or lose consciousness need emergency care.
Your doctor will conduct a physical exam to look for signs of damage to your nervous system, including:
If your doctor suspects you have a chronic SDH, you’ll need to undergo further testing. Symptoms of this condition are similar to symptoms of several other disorders and illnesses that affect the brain, such as:
Tests like magnetic resonance imaging (MRI) and computed tomography (CT) can lead to a more accurate diagnosis.
An MRI uses radio waves and a magnetic field to produce images of your organs. A CT scan uses several X-rays to make cross-sectional pictures of bones and soft structures in your body.
Your doctor will focus on protecting your brain from permanent damage and making symptoms easier to manage. Anticonvulsant drugs can help reduce the severity of seizures or stop them from occurring. Drugs known as corticosteroids relieve inflammation and are sometimes used to ease swelling in the brain.
Chronic SDH can be treated surgically. The procedure involves making tiny holes in the skull so blood can flow out. This gets rid of pressure on the brain.
If you have a large or thick clot, your doctor can temporarily remove a small piece of skull and take out the clot. This procedure is called a craniotomy.
If you have symptoms associated with a chronic SDH, you’ll likely need surgery. The outcome of a surgical removal is successful for 80 to 90 percent of people. In some cases, the hematoma will return after surgery and must be removed again.
You can protect your head and reduce your risk of chronic SDH in several ways.
Wear a helmet when riding a bicycle or motorcycle. Always fasten your seat belt in the car to decrease your risk of a head injury during an accident.
If you work in a hazardous occupation such as construction, wear a hard hat and use safety equipment.
If you’re over age 60, use extra caution in your daily activities to prevent falls.
Written by: Amanda Delgado and Marijane Leonard
Medically reviewed on: Dec 21, 2015: Deborah Weatherspoon, Ph.D, MSN, RN, CRNA
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