A chronic subdural hematoma (SDH) is a pool (or collection) of blood on the brain’s surface under the dura, which is the outer covering of the brain. It usually begins forming several days or weeks after bleeding initially starts. This bleeding is usually due to a head injury. Other names for this condition are chronic subdural hemorrhage and subdural hygroma. These hematomas don’t always produce symptoms. When they do, they generally require 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 that are not related to an 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 that puts increasing pressure on your brain.
If you are at least 60 years old, you face a higher risk for this type of hematoma due to brain atrophy. This condition, in which brain tissue shrinks as part of the normal aging process, makes the brain more susceptible to bleeds. This is because the 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:
- trouble walking
- impaired memory
- problems with vision
- trouble with speech
- trouble swallowing
- numb or weak face, arms, or legs
The exact symptoms that appear depend on where your hematoma is and how large it is. Some symptoms occur more often than others. Up to 80 percent of people with this type of hematoma have headaches, according to UCLA Neurosurgery. (UCLA)
If your clot is large then paralysis—or the loss of the ability to move—can occur. You might also slip into a coma (become unconscious). 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. These include poor coordination, problems with walking, mental impairment, and difficulty balancing. If your doctor suspects that you have a chronic SDH, you will need to undergo further testing. This condition has similar symptoms to several other disorders and illnesses that affect the brain. Examples of these conditions are dementia, lesions, encephalitis, and strokes. Tests such as 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 body’s organs and other structures. A CT scan uses several X-rays to make cross-sectional pictures of your body’s soft structures and bones.
Your doctor will focus on guarding your brain from permanent damage and making symptoms easier to manage. Anticonvulsant drugs such as lamotrigine can help reduce the severity of seizures or stop them from occurring. Drugs that relieve inflammation are sometimes used to ease swelling in the brain. These are known as corticosteroids.
Chronic SDH can be treated surgically. The procedure involves making tiny holes in the skull so that the blood can flow out. This gets rid of the pressure on the brain. If you have a large clot, your doctor can drill a bigger hole to remove it. This procedure, called a craniotomy, is also used for thicker clots.
If you have symptoms associated with a chronic SDH, you will likely require surgery. The outcome of a surgical removal is successful for 80 to 90 percent of patients, according to UCLA Neurosurgery. (UCLA) In some cases, the hematoma returns 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 suffering 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.