Alternate Names: Subdural hemorrhage - chronic; Subdural hematoma - chronic
Causes and Risks:
Subdural means below the dura (the dura mater is the outer membrane covering the brain).
Chronic subdural hematoma develops when veins that are located between the membranes covering the brain slowly leak blood after a head injury. The head injury could be as obvious as a major accident or seemingly as trivial as a minor bump to the head. In many cases, the head injury may not even be remembered. The blood collects as a mass (hematoma) that presses on the brain tissue. This causes loss of brain function, which may progressively worsen as the hematoma enlarges.
Risks include head injury, very young or old age, chronic use of aspirin or blood thinner (anti-coagulant) medication, and alcoholism or chronic alcohol use. Other important factors include a history of any disorder that may increase the risk of falling, and organic brain syndromes where confusion and cognitive impairment are already present and may mask symptoms of chronic subdural hematoma.
Chronic subdural hematoma occurs in about 1 out of 10,000 people. It is most common in infants and the elderly, especially people over age 75, but it may occur in people of all ages. If seen in an infant, the healthcare provider must consider child abuse and pursue the appropriate work-up.
Prevention:
Chronic subdural hematoma often cannot be prevented once a head injury has occurred.
Minimize the risk of head injury by using proper safety equipment (such as hard hats, bicycle or motorcycle helmets, and seat belts) when involved in activities that may result in brain injury.
Symptoms:
Signs and Tests:
The health care provider should be consulted for any head injury that results in even a brief loss of consciousness, or if other symptoms are present after a head injury even without loss of consciousness.
Chronic subdural hematoma may be diagnosed after the health care provider has ruled out other possible causes (such as intracerebral hemorrhage) of decreased mental functioning and other symptoms after a history of head injury. Examination may show focal neurologic deficits (localized, specific function changes). The skull may be tender to tapping on one or both sides.
A cranial CT scan or a cranial MRI may confirm the diagnosis of subdural hematoma and will pinpoint the exact location.
Treatment:
Treatment goals include controlling symptoms and minimizing or preventing permanent damage to the brain.
Medications used will vary according to the type and severity of symptoms and brain damage. Corticosteroid medications may be used to reduce inflammation and swelling of the brain.Anticonvulsant medications such as phenytoin may be used to control or prevent seizures.
Surgery may be required. This may include drilling a small hole in the skull to relieve pressure and allow blood to be drained. Large hematomas or solid blood clots may need to be removed through a larger opening in the skull (craniotomy).
Prognosis:
Chronic subdural hematoma may result in death or permanent brain injury if untreated or, occasionally, even if treated. Symptoms such as seizures may persist for several months even after treatment. Seizures may begin as much as 2 years after the injury.
In adults, most recovery occurs in the first 6 months, with some improvement over approximately 2 years. Children usually recover more quickly and completely than adults. Incomplete recovery is the result of brain damage. Recurrent chronic subdural hematoma is common and occurs in approximately 30% of individuals treated for chronic subdural hematoma.
Complications:
Because of the risk of permanent brain damage, a health care provider should be called promptly if symptoms of chronic subdural hematoma appear.
Go to the emergency room or call the local emergency number (such as 911) if emergency symptoms develop, including convulsions/seizures, decreased responsiveness, loss of consciousness, enlarged pupils, and uneven pupil size.
