Subdural Hematoma

What Is It?

A subdural hematoma, also called a subdural hemorrhage, occurs when a blood vessel ruptures (bursts) and blood builds up between the brain and the brain's tough outer lining. A subdural hematoma is a close relative of other hemorrhages that can occur at the surface of the brain, including epidural hematoma and subarachnoid hemorrhage. These hemorrhage types each cause blood to collect beneath a different layer of the meninges, the three-layer protective covering of the brain. In the case of a subdural hematoma, blood collects immediately beneath the outermost layer, the dura mater. A subdural hematoma is a life-threatening problem because it can compress the brain.

Most subdural hemorrhages are caused when trauma to the head damages tiny veins within the meninges. In young, healthy people, bleeding usually is triggered by a significant impact, such as might occur in a high-speed motor vehicle accident. In contrast, older people may develop a subdural hemorrhage after minor trauma, such as a falling out of a chair. Bleeding within the head after a minor injury is also more common in people taking medications that thin the blood and in people who abuse alcohol or have seizures.

Subdural bleeding that develops shortly after a serious blow to the head is known as an acute subdural hemorrhage. Acute subdural hemorrhages develop in 5% to 20% of people with severe head injury, typically those who fall from a considerable height. This type of bleeding occurs three times more often in men than in women. In acute subdural hemorrhage, the rapid accumulation of blood causes pressure to rise within the brain, and can result in loss of consciousness, paralysis or death. The force required to trigger this type of bleeding can cause several different injuries to the brain and spinal cord at the same time.

When bleeding develops slowly, typically over a period of weeks to months, it is known as a chronic subdural hemorrhage. This form of bleeding is much more common in older people. Most of those affected over age 50. The head trauma that causes chronic subdural hemorrhage is often minor, and up to one-half of those affected cannot recall a head injury.

Symptoms

Acute subdural hemorrhage usually develops after severe head trauma. Injuries that result in a subdural hemorrhage are typically forceful enough to cause a temporary loss of consciousness (concussion). Bleeding associated with a subdural hemorrhage occurs slowly, because the damaged blood vessels are small veins. Usually, in the minutes to hours after head injury, the person recovers from a concussion and then gradually loses consciousness from subdural bleeding. Other common symptoms include severe headache, weakness on one side of the body, seizures and changes in vision or speech.

Chronic subdural hemorrhages produce more subtle symptoms, which may continue for more than a month before the diagnosis is recognized. These symptoms include:

• Mild headache
• Nausea or vomiting
• Change in personality
• Memory loss
• Loss of balance or difficulty walking
• Double vision
• Weakness, numbness or tingling in arms or legs

The symptoms caused by chronic subdural hemorrhage can mimic other common conditions, including strokes and brain tumors. Occasionally, the gradual memory loss and personality changes can be mistaken for dementia.

Diagnosis

All head injuries should be evaluated promptly by a physician, especially if there has been any loss of consciousness. A doctor usually will want to know:

• How the injury occurred
• What symptoms developed
• Whether there have been head injuries in the past (since repeat injuries are more likely to cause serious damage)
• Whether the person has other medical problems
• What medications the person is taking
• Whether the person has been drinking alcohol or using drugs
• Whether there are symptoms of other injuries (neck pain, shortness of breath, etc.)

The doctor will perform a thorough physical and neurological exam. He or she will check blood pressure and pulse; vision and the way the eyes respond to light; reflexes and balance; and the ability to answer questions and remember things. If the doctor suspects there is bleeding in the head, he or she will order a computed tomography (CT) scan. This type of scan is the best way to determine the location and amount of bleeding, as well as any injuries to the brain, skull or neck.

A doctor may suspect a chronic subdural hemorrhage if an older patient develops new neurological symptoms, especially if there has been a fall or minor trauma to the head.

Expected Duration

An acute subdural hemorrhage develops over minutes to hours. If not diagnosed and treated promptly, it can cause severe brain injury and death.

A chronic subdural hemorrhage develops over weeks to months. Symptoms may develop slowly and may be subtle.

As is the case with any brain injury, symptoms can be slow to go away after a subdural hematoma is treated, and some symptoms may be permanent. Occasionally, a subdural hematoma is small enough that doctors will allow the blood to deteriorate and be reabsorbed gradually by the body without surgery. This process requires months, but it is sometimes the safest treatment plan.

Prevention

Accidents, including head injuries, are the leading cause of death in young people. Many of these accidents are related to drugs and alcohol, and many others could be prevented with simple precautions or safety equipment.

To help prevent head injuries:

• If you drink alcohol, drink in moderation. Never drive after drinking or using drugs.
• If your job involves working high above the ground, use approved safety equipment to prevent accidental falls. Never work in a high place if you feel lightheaded or unsteady, if you have been drinking alcohol or if you are taking medication that can make you dizzy or affect your balance.
• Have your vision checked regularly, since poor vision can increase your risk of falls and other types of accidents. This is especially true if you are elderly or if you work in high places.
• If you are an older adult, clear your home or apartment of hazards that could cause you to trip and fall, such as throw rugs and extension cords. If you feel unsteady on your feet, consider using a cane or walker.
• If you play a contact sport such as football or soccer and you experience a significant head injury, allow adequate time for healing before you start playing again. After a head injury, the delicate veins beneath the dura mater can require up to 15 days to fully repair themselves, even if symptoms go away much sooner. A repeated injury that occurs during this fragile repair period is likely to result in hemorrhage. This is called the second impact syndrome.

Medications that thin the blood including warfarin (Coumadin), aspirin and other anti-inflammatories increase your risk of bleeding within the head. If you take blood thinners, make sure that you have close medical supervision with blood tests to monitor your dose.

Treatment

An acute subdural hemorrhage requires immediate medical attention. In most cases, emergency surgery must be done to drain the hematoma and to control bleeding. Patients are monitored in an intensive care unit with careful attention to breathing, blood pressure and neurological function. Occasionally, the person will need medications or will need to breathe through a ventilator to prevent swelling of the brain.

In contrast, only some chronic subdural hemorrhages require emergency treatment, and others do not require treatment at all. Most physicians will recommend surgery for larger hemorrhages and those that cause neurological symptoms. However, treatment with bed rest, medications and observation may be reasonable for smaller hematomas that cause minimal or no symptoms.

People who develop a subdural hemorrhage are at risk of developing seizures, even after the hematoma has been treated. To prevent seizures, some physicians will prescribe anticonvulsant (antiseizure) medications for a year or longer.

When To Call A Professional

Call for emergency assistance if you find someone unconscious at an accident scene. Also seek immediate attention if someone with a head injury experiences any of the following symptoms:

• Drowsiness or a decrease in alertness
• Nausea or vomiting
• Confusion or amnesia
• Difficulty walking or poor coordination
• Slurred speech
• Double vision
• Irrational or aggressive behavior
• Seizures
• Numbness or paralysis in any part of the body

Even if a head injury appears minor, and the symptoms are mild, certain people are at high risk of serious bleeding. Call a doctor or go to an emergency room immediately if an injured person:

• Is elderly
• Takes medications to thin the blood
• Has a bleeding disorder
• Has a history of heavy alcohol use

Prognosis

The outlook for acute subdural hemorrhages generally is poor, often because of associated injuries to the brain, regardless of the size of the hematoma. Up to half of those with severe head injuries die, and many of those who survive may be left with permanent neurological problems. The prognosis is best in people who:

• Are unconscious for only short periods of time
• Have few neurological symptoms when evaluated by a doctor
• Are younger than age 50
• Do not abuse alcohol
• Do not have other associated brain injuries
• Receive prompt medical attention

In comparison, the prognosis for chronic subdural hemorrhage is quite favorable. Fewer than 10% of those affected die, and up to 80% are able to resume normal functioning. The prognosis is best in those who are awake, alert and have few neurological symptoms at the time of evaluation.

Additional Info

National Institute of Neurological Disorders and Stroke

P.O. Box 5801

Bethesda, MD 20824

Phone: 301-496-5751

Toll-Free: 1-800-352-9424

TTY: 301-468-5981

http://www.ninds.nih.gov/

Allergy & Asthma Network Mothers of Asthmatics (AANMA)

2751 Prosperity Ave.

Suite 150

Fairfax, VA 22031

Toll-Free: 1-800-878-4403

Fax: 703-573-7794

http://www.aanma.org/

American Association of Neurological Surgeons

5550 Meadowbrook Drive

Rolling Meadows, IL 60008

Phone: 847-378-0500

Toll-Free: 1-888-566-2267

Fax: 847-378-0600

Email: info@aans.org

http://www.neurosurgerytoday.org/

Brain Injury Association of America

8201 Greensboro Drive

Suite 611

McLean, VA 22102

Phone: 703-761-0750

Toll-Free: 1-800-444-6443

Fax: 703-761-0755

Email: familyhelpline@biausa.org

http://www.biausa.org/