A chronic subdural hematoma is an "old" collection of blood and blood breakdown products between the surface of the brain and its outermost covering (the dura). The chronic phase of a subdural hematoma begins several weeks after the first bleeding.
A subdural hematoma develops when the tiny veins that run between the dura and surface of the brain (bridging veins) tear and leak blood. This is usually the result of a head injury.
A collection of blood then forms over the surface of the brain. In a chronic subdural collection, blood leaks from the veins slowly over time, or a fast hemorrhage is left to clear up on its own.
A subdural hematoma is more common in the elderly because of normal brain shrinkage that occurs with aging. This shrinkage stretches and weakens the bridging veins. These veins are more likely to break in the elderly, even after a minor head injury. Rarely, a subdural hematoma can occur without known cause (i.e., not from an accident or injury).
Long term, heavy alcohol use
Long-term use of aspirin, anti-inflammatory drugs, such as ibuprofen, or blood thinning (anticoagulant) medication
Diseases associated with reduced blood clotting
In some cases, there may be no symptoms However, depending on the size of the hematoma and where it presses on the brain, any of the following symptoms may occur:
Your health care provider will ask questions about your medical history. The physical exam will carefully check your brain and nervous system to check for problems with:
Because the symptoms and signs are often subtle, if there is any suspicion of a hematoma, a head CT or head MRI scan will be done to further evaluate your symptoms.
The goal is to control symptoms and minimize or prevent permanent damage to the brain.
Anticonvulsant medications such as carbamazepine, lamotrigine or levetiracetam may be used to control or prevent seizures.
Corticosteroid medications may be used to temporarily reduce any swelling of the brain.
Surgery may be required. This may include drilling small holes in the skull to relieve pressure and allow blood and fluids to be drained. Large hematomas or solid blood clots may need to be removed through a larger opening in the skull (craniotomy).
Hematomas that do not cause symptoms may not require treatment.
Chronic subdural hematomas that cause symptoms usually do not heal on their own over time. They often require surgery, especially when there are neurologic problems, seizures, or chronic headaches.
Some chronic subdural hematomas return after drainage, and a second surgery may be necessary.
Because of the risk of permanent brain damage, call a health care provider promptly if you or someone else develops symptoms of chronic subdural hematoma. For example, call if you see symptoms of confusion, weakness ,or numbness weeks or months after a head injury in an older person.
Take the person to the emergency room or call 911 if the person:
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.