Health Encyclopedia

Subdural hematoma

Definition

A subdural hematoma is a collection of blood on the surface of the brain.

Alternative Names

Subdural hemorrhage

Causes, incidence, and risk factors

Subdural hematomas are usually the result of a serious head injury. When they occur in this way, it is called an "acute" subdural hematoma. Acute subdural hematomas are among the deadliest of all head injuries. The bleeding fills the brain area very rapidly, leaving little room for the brain, and are associated with brain injury.

Subdural hematomas can also after a very minor head injury, especially in the elderly. These go unnoticed for many days to many weeks, and are called "chronic" subdural hematomas. During a subdural hematoma, tiny veins between the surface of the brain and its outer covering (the dura) stretch and tear, allowing blood to collect. In the elderly, the veins are often already stretched because of brain atrophy (shrinkage).

Some subdural hematomas occur without cause (spontaneously).

The following increase your risk for a subdural hematoma:

Head injury
Very young or very old age
Anticoagulant medication (blood thinners)
Long term abuse of alcohol

Symptoms

Recent head injury
Loss of consciousness after head injury
Headache
Weakness
Numbness
Can't speak
Slurred speech
Nausea and vomiting
Lethargy
Seizures

In infants:

Bulging fontanelles
Increased head circumference
Separated sutures
Irritability
High-pitched cry
Focal seizures
Generalized tonic-clonic seizure

Signs and tests

Always get medical help after a head injury. Older persons should receive medical care if they shows signs of memory problems or mental decline. An exam should include a complete neurologic exam.

Your doctor may order a brain imaging study if you have any of the following symptoms:

Weakness
Numbness
Inability to speak
Slurred speech
Persistent headache
Abnormal level of consciousness
Recent cognitive decline in an elderly person, even without of head injury

A CT scan or MRI scan would likely be done to evaluate for the presence of a subdural hematoma.

Treatment

A subdural hematoma is an emergency condition!

Emergency surgery may be needed to reduce pressure within the brain. This may involve drilling a small hole in the skull, which relieves pressure and allows the hematoma to drain. Large hematomas or solid blood clots may need to be removed through a procedure called a craniotomy, which creates a larger opening in the skull.

Medicines used to treat a subdural hematoma depend on the type of subdural hematoma, the severity of symptoms, and how much brain damage there is. Diuretics may be used to reduce swelling. Anti-convulsant medications such as phenytoin may be used to control or prevent seizures.

Expectations (prognosis)

The outlook following a subdural hematoma varies widely depending on the type of head injury, the size of the blood collection, and how quickly treatment is obtained.

Acute subdural hematomas present the largest challenge, with high rates of death and injury. Subacute and chronic subdural hematomas have good outcomes in most cases, with symptoms going away after the blood collection is drained.

There is a high frequency of seizures following a subdural hematoma, but these are usually well controlled with medication.

Complications

Temporary or permanent weakness, numbness, difficulty speaking
Seizures
Brain herniation
Persistent symptoms such as memory loss, dizziness, headache, anxiety, and difficulty concentrating

Calling your health care provider

A subdural hematoma requires emergency medical attention. Call 911 or your local emergency number, or go immediately to an emergency room.

Spinal injuries often occur with head injuries, so try to keep the person's neck still if you must move him or her before help arrives.

Prevention

Always use safety equipment at work and play to reduce your risk of a head injury. For example, use hard hats, bicycle or motorcycle helmets, and seat belts.

Review Date:7/14/2006
Reviewed By:J.A. Lee, M.D., Division of Surgery, UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network.

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