A stroke is an interruption of the blood supply to any part of the brain. A stroke is sometimes called a "brain attack."

Every 45 seconds, someone in the United States has a stroke. A stroke can happen when:

• A blood vessel carrying blood to the brain is blocked by a blood clot. This is called an ischemic stroke.
• A blood vessel breaks open, causing blood to leak into the brain. This is a hemorrhagic stroke.

If blood flow is stopped for longer than a few seconds, the brain cannot get blood and oxygen. Brain cells can die, causing permanent damage.

ISCHEMIC STROKE

This is the most common type of stroke. Usually this type of stroke results from clogged arteries, a condition called atherosclerosis. (See stroke secondary to atherosclerosis.) Fatty deposits collect on the wall of the arteries, forming a sticky substance called plaque. Over time, the plaque builds up. Often, the plaque causes the blood to flow abnormally, which can cause the blood to clot. There are two types of clots:

• A clot that stays in place in the brain is called a cerebral thrombus.
• A clot that breaks loose and moves through the bloodstream to the brain is called a cerebral embolism.

Another important cause of cerebral embolisms is a type of arrhythmia called atrial fibrillation. Other causes of ischemic stroke include endocarditis, an abnormal heart valve, and having a mechanical heart valve. A clot can form on a heart valve, break off, and travel to the brain. For this reason, those with mechanical or abnormal heart valves often must take blood thinners.

HEMORRHAGIC STROKE

A second major cause of stroke is bleeding in the brain hemorrhagic stroke. This can occur when small blood vessels in the brain become weak and burst. Some people have defects in the blood vessels of the brain that make this more likely. The flow of blood after the blood vessel ruptures damages brain cells.

STROKE RISKS

High blood pressure is the number one reason that you might have a stroke. The risk of stroke is also increased by age, family history of stroke, smoking, diabetes, high cholesterol, and heart disease.

Certain medications increase the chances of clot formation, and therefore your chances for a stroke. Birth control pills can cause blood clots, especially in woman who smoke and who are older than 35.

Men have more strokes than women. But, women have a risk of stroke during pregnancy and the weeks immediately after pregnancy.

Cocaine use, alcohol abuse, head injury, and bleeding disorders increase the risk of bleeding into the brain.

See also:

• Stroke secondary to carotid dissection (bleeding from the carotid arteries)
• Stroke secondary to carotid stenosis (narrowing of the carotid arteries)
• Stroke secondary to cocaine use
• Stroke secondary to FMD (fibromuscular dysplasia)
• Stroke secondary to syphilis
• Hemorrhagic stroke
• Arteriovenous malformation (AVM)

The symptoms of stroke depend on what part of the brain is damaged. In some cases, a person may not even be aware that he or she has had a stroke.

Usually, a SUDDEN development of one or more of the following indicates a stroke:

• Weakness or paralysis of an arm, leg, side of the face, or any part of the body
• Numbness, tingling, decreased sensation
• Vision changes
• Slurred speech, inability to speak or understand speech, difficulty reading or writing
• Swallowing difficulties or drooling
• Loss of memory
• Vertigo (spinning sensation)
• Loss of balance or coordination
• Personality changes
• Mood changes (depression, apathy)
• Drowsiness, lethargy, or loss of consciousness
• Uncontrollable eye movements or eyelid drooping

If one or more of these symptoms is present for less than 24 hours, it may be a transient ischemic attack (TIA). A TIA is a temporary loss of brain function and a warning sign for a possible future stroke.

In diagnosing a stroke, knowing how the symptoms developed is important. The symptoms may be severe at the beginning of the stroke, or they may progress or fluctuate for the first day or two (stroke in evolution). Once there is no further deterioration, the stroke is considered completed.

During the exam, your doctor will look for specific neurologic, motor, and sensory deficits. These often correspond closely to the location of the injury in the brain. An examination may show changes in vision or visual fields, abnormal reflexes, abnormal eye movements, muscle weakness, decreased sensation, and other changes. A "bruit" (an abnormal sound heard with the stethoscope) may be heard over the carotid arteries of the neck. There may be signs of atrial fibrillation.

Tests are performed to determine the type, location, and cause of the stroke and to rule out other disorders that may be responsible for the symptoms. These tests include:

• Head CT or head MRI -- used to determine if the stroke was caused by bleeding (hemorrhage) or other lesions and to define the location and extent of the stroke.
• ECG (electrocardiogram) -- used to diagnose underlying heart disorders.
• Echocardiogram -- used if the cause may be an embolus (blood clot) from the heart.
• Carotid duplex (a type of ultrasound) -- used if the cause may be carotid artery stenosis (narrowing of the major blood vessels supplying blood to the brain).
• Heart monitor -- worn while in the hospital or as an outpatient to determine if a heart arrhythmia (like atrial fibrillation) may be responsible for your stroke.
• Cerebral (head) angiography -- may be done so that the doctor can identify the blood vessel responsible for the stroke. Mainly used if surgery is being considered.
• Blood work may be done to exclude immune conditions or abnormal clotting of the blood that can lead to clot formation.

A stroke is a medical emergency. Physicians have begun to call it a "brain attack" to stress that getting treatment immediately can save lives and reduce disability. Treatment varies, depending on the severity and cause of the stroke. For virtually all strokes, hospitalization is required, possibly including intensive care and life support.

The goal is to get the person to the emergency room immediately, determine if he or she is having a bleeding stroke or a stroke from a blood clot, and start therapy -- all within 3 hours of when the stroke began.

IMMEDIATE TREATMENT

Thrombolytic medicine, such as tPA, breaks up blood clots and can restore blood flow to the damaged area. People who receive this medicine are more likely to have less long-term impairment. However, there are strict criteria for who can receive thrombolytics. The most important is that the person be examined and treated by a specialized stroke team within 3 hours of when the symptoms start. If the stroke is caused by bleeding rather than clotting, this treatment can make the damage worse -- so care is needed to diagnose the cause before giving treatment.

In other circumstances, blood thinners such as heparin and Coumadin are used to treat strokes. Aspirin may also be used.

Other medications may be needed to control associated symptoms. Pain killers may be needed to control severe headache. Medicine may be needed to control high blood pressure.

Nutrients and fluids may be necessary, especially if the person has swallowing difficulties. The nutrients and fluids may be given through an intravenous tube (IV) or a feeding tube in the stomach (gastrostomy tube). Swallowing difficulties may be temporary or permanent.

For hemorrhagic stroke, surgery is often required to remove pooled blood from the brain and to repair damaged blood vessels.

LONG-TERM TREATMENT

The goal of long-term treatment is to recover as much function as possible and prevent future strokes. Depending on the symptoms, rehabilitation includes speech therapy, occupational therapy, and physical therapy. The recovery time differs from person to person.

Certain therapies, such as repositioning and range-of-motion exercises, are intended to prevent complications related to stroke, like infections and bed sores. People should stay active within their physical limitations. Sometimes, urinary catheterization or bladder/bowel control programs may be needed to control incontinence.

The person's safety must be considered. Some people with stroke appear to have no awareness of their surroundings on the affected side. Others show indifference or lack of judgment, which increases the need for safety precautions. For these people, friends and family members should repeatedly reinforce important information, like name, age, date, time, and where they live, to help the person stay oriented.

Caregivers may need to show the person pictures, repeatedly demonstrate how to perform tasks, or use other communication strategies, depending on the type and extent of the language problems.

In-home care, boarding homes, adult day care, or convalescent homes may be required to provide a safe environment, control aggressive or agitated behavior, and meet medical needs.

Behavior modification may be helpful for some people in controlling unacceptable or dangerous behaviors.

Family counseling may help in coping with the changes required for home care. Visiting nurses or aides, volunteer services, homemakers, adult protective services, and other community resources may be helpful.

Legal advice may be appropriate. Advance directives, power of attorney, and other legal actions may make it easier to make ethical decisions regarding the care of a person who has had a stroke.

Additional support and resources are available from the American Stroke Association -- www.strokeassociation.org.

The long-term outcome from a stroke depends on the extent of damage to the brain, the presence of any associated medical problems, and the likelihood of recurring strokes.

Of those who survive a stroke, many have long-term disabilities, but about 10% of those who have had a stroke recover most or all function. Fifty percent are able to be at home with medical assistance while 40% become residents of a long-term care facility like a nursing home.

• Problems due to loss of mobility (joint contractures, pressure sores)
• Permanent loss of movement or sensation of a part of the body
• Bone fractures
• Muscle spasticity
• Permanent loss of brain functions
• Reduced communication or social interaction
• Reduced ability to function or care for self
• Decreased life span
• Side effects of medications
• Aspiration
• Malnutrition

Call your local emergency number (such as 911) if someone has symptoms of a stroke. Stroke requires immediate treatment!

To help prevent a stroke:

• Get screened for high blood pressure at least every 2 years, especially if you have a family history of high blood pressure.
• Have your cholesterol checked. If you are high risk, your LDL "bad" cholesterol should be lower than 70 mg/dL.
• If you have high blood pressure, diabetes, high cholesterol, and heart disease, make sure you follow your doctor's treatment recommendations.
• Follow a low-fat diet.
• Quit smoking.
• Exercise regularly -- 30 minutes a day if you are not overweight; 60 - 90 minutes a day if you are overweight.
• Do not drink more than 1 to 2 alcoholic drinks a day.

Aspirin therapy (81mg a day or 100mg every other day) is now recommended for stroke prevention in women under 65 as long as the benefits outweigh the risks. It should be considered for women over age 65 only if their blood pressure is controlled and the benefit is greater than the risk of gastrointestinal bleeding and brain hemorrhage. Ask your doctor if aspirin is right for you.

Your doctor may also recommend that you take aspirin or another blood thinner if you have had a TIA or stroke in the past, or if you currently have a heart arrhythmia (like atrial fibrillation), mechanical heart valve, congestive heart failure, or risk factors for stroke.

Carotid endarterectomy (removal of plaque from the carotid arteries) may help prevent new strokes from occurring in people with large blockage in their blood vessels.

Mosca L, Banka CL, Benjamin EJ, et al. Evidence-Based Guidelines for Cardiovascular Disease Prevention in Women: 2007 Update. Circulation. 2007; Published online before print February 19, 2007.

American Heart Association. Heart Disease and Stroke Statistics -- 2005 Update. Dallas, Texas: American Heart Association; 2005.

Marx JA, Hockberger RS, Walls RM, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th ed. St. Louis, Mo: Mosby; 2002.

Goldman L, Ausiello D, eds. Cecil Textbook of Medicine, 22nd ed. Philadelphia, Pa: Saunders; 2004.