Brain Attack - Stroke

A stroke is the death of brain tissue that occurs when the brain does not get enough blood and oxygen.

What is going on in the body?

Strokes are classified as ischemic strokes or hemorrhagic strokes. Ischemic strokes happen when the blood supply to the brain is interrupted. The brain cells then die from lack of oxygen. Hemorrhagic strokes occur when blood vessels in the brain burst and release blood into the area around the brain cells. The blood then damages the brain cells. The products released when cells die cause swelling in the brain. Since the skull doesn't allow much room for expansion, this swelling can damage the brain tissue even further.

Examples of ischemic strokes are:

Hemorrhagic strokes occur when there is bleeding into the brain caused by damage to the blood vessels. A hemorrhagic stroke may be caused by:

Stroke is the third leading cause of death in the US and many other countries, right after heart disease and cancer.

What are the causes and risks of the condition?

Strokes are caused by an interruption of the blood flow to brain cells or by damage to brain cells.

The American Heart Association has recently issued guidelines for stroke prevention. The guidelines discuss risk factors for stroke in 3 categories: nonmodifiable, well-documented modifiable, and less well-documented or potentially modifiable.

The nonmodifiable factors are ones that cannot be changed by the individual and include:

Well-documented modifiable risk factors are those that can be changed by the individual in conjunction with his or her healthcare provider. These factors are linked to stroke by strong research findings, and there is documented proof that changing the risk factor lowers a person's risk of stroke. These factors include:

Less well-documented or potentially modifiable risk factors for stroke are those that have less proof of either a link to stroke or the impact of modifying the risk factor. These factors include:

Several recent studies have identified factors that seem to increase or decrease the risk of stroke in particular groups of people. These studies, which warrant further investigation, include these findings:

What are the signs and symptoms of the condition?

Strokes can cause many different signs and symptoms, depending on the area of the brain that is damaged. Some people have multiple areas of damage. Most strokes begin suddenly, develop rapidly, and cause brain damage within minutes. Signs or symptoms may include:

How is the condition diagnosed?

The first step in diagnosis of stroke is a medical history and physical exam. This may be all that is needed to make the diagnosis. In other cases, further tests may be needed.

Cranial MRIs and cranial CT scans may be ordered to show the type, size, and location of the stroke. They can also show whether or not there is bleeding in the brain, which can help with some treatment decisions.

Other tests may be ordered to help determine the cause of the stroke. For instance, a special X-ray test of the neck arteries can detect blockage. Certain X-ray tests of the heart can show heart failure or changes from a heart attack. A heart tracing, or ECG, can show abnormal heartbeats, such as atrial fibrillation, or certain changes from a heart attack.

What can be done to prevent the condition?

The American Heart Association guidelines for stroke prevention address both modifiable and less well-documented or potentially modifiable risk factors.

Measures to reduce the modifiable risk of high blood pressure, a major cause of stroke, include:

Other measures to reduce an individual's modifiable risk factors for stroke may include:

Measures to reduce less well-documented or potentially modifiable risks for stroke may include:

Some people have early warning signs that they are at risk for strokes. The most common warning sign is what is known as a transient ischemic attack, or TIA. This is a type of reversible stroke that often goes away after a few minutes. These people can often get treatment that will prevent a stroke in the future. For instance, they may be advised to take aspirin or have carotid artery surgery to correct a blockage in a neck artery.

What are the long-term effects of the condition?

Strokes can cause death or permanent disability. Though many people recover some function in the first several months after a stroke, others show no improvement. Some people have several small strokes over time and slowly get worse with each one.

What are the risks to others?

Strokes are not contagious and pose no risk to others.

What are the treatments for the condition?

Most people with strokes are treated right away with only aspirin if they do not have bleeding into the brain. This only serves to help prevent further strokes. In cases when a stroke is caught in the first few hours, a clot-busting medication may be used to reverse a stroke. This is why early recognition of a stroke can be important.

If someone has the early warning signs of stroke, the emergency medical system should be contacted immediately.

These signs include a sudden onset of:

Specific types of medication may be needed in special cases. For instance, those with a heart infection may be given antibiotics. Those with arteritis are often given corticosteroids, such as prednisone, to reduce inflammation in the brain.

If an individual has significant narrowing of the carotid arteries, a carotid endarterectomy may be recommended to widen them. This surgical procedure removes the cholesterol plaques and may prevent future strokes. The decision to perform surgery will depend on the person's neurological status, the type of plaque clogging the artery, and whether the plaque has a break in it, known as a rupture.

Supportive therapy may also be needed with some strokes. This may include an artificial breathing machine, or ventilator, and an artificial feeding tube if the person cannot swallow.

Rehabilitation services can help to improve a person's function after a stroke. Physical therapy and other therapy, such as speech therapy or occupational therapy, may be used to maximize recovery.

What are the side effects of the treatments?

Side effects depend on the treatments used. For instance, aspirin may cause allergic reactions, stomach upset, or bleeding. Clot-busting medications can cause excessive bleeding. A ventilator may sometimes cause damage to the lungs or an infection.

A carotid artery endarterectomy can cause bleeding, infections, and allergic reactions to the anesthesia. On rare occasions, carotid endarterectomy can cause a stroke or heart attack to occur.

What happens after treatment for the condition?

After the person is stable, treatment of the risk factors for stroke, as well as the cause of the stroke, is important to prevent further strokes. For instance, stopping smoking and controlling high blood pressure, diabetes, and high cholesterol are advised for most people.

Those with arteritis are often maintained on medications to reduce inflammation for long periods. Those with clots in the heart are often put on medications to thin the blood, such as warfarin.

Many people need assistance of one form or another after a stroke. This may range from using a walking cane to needing 24-hour-a-day skilled nursing care. Ongoing therapy to improve function is usually advised for at least 6 months if the person is able.

How is the condition monitored?

People having a stroke are often admitted to the hospital for close monitoring. Once the person is stable, he or she can often be sent home or to a skilled nursing facility or rehabilitation center for further therapy.

Other monitoring is related to the cause. For instance, those with clots in their heart need repeat blood tests, such as a PT test, to monitor the effects of medications used to thin the blood. Any new or worsening symptoms should be reported to the healthcare provider.

Author:Adam Brochert, MD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:01/31/01
Reviewer:Eileen McLaughlin, RN, BSN
Date Reviewed:07/13/01

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