Multiple: Stroke

Definition
Description
Demographics
Causes and Symptoms
Diagnosis
Treatment
Prognosis
Prevention
The Future
For more information

Definition

Stroke is a life-threatening condition that occurs when the blood supply to a part of the brain is suddenly cut off or when brain tissue is damaged by bleeding into the brain. There are two main types of stroke. Ischemic stroke occurs when a clot formed in the artery or coming from elsewhere in the artery system blocks an artery to the brain; this type accounts for about 80 percent of strokes. The other type, hemorrhagic stroke, occurs when a blood vessel in the brain bursts, allowing blood to spill out into brain tissue. The blood upsets the chemical balance that the nerve cells in the brain need to function.

Description

Stroke is usually a sudden occurrence. Some people have a warning event called a transient ischemic attack (TIA) or mini-stroke. A TIA has the

same symptoms as a full-blown stroke but goes away in a few minutes or hours, leaving no permanent effects. It is, however, an indication that the person is at risk of a major stroke and should see their doctor right away. A TIA offers the person an opportunity to take preventive action.

Stroke has five major signs or symptoms. The American Stroke Association has a quick symptom checklist called “Give Me 5”

• Walk: Is the person having trouble with balance or coordination?
• Talk: Is speech difficult or slurred? Is the person's face drooping?
• Reach: Is one side of the body weak or numb?
• See: Is vision partly or entirely lost?
• Feel: Does the person have a sudden severe headache with no obvious cause?

A person with stroke can have more than one of these symptoms at the same time. The important feature to keep in mind is that the symptoms come on suddenly, which helps in distinguishing stroke from other causes of dizziness, vision problems, or headache.

Demographics

According to the Centers for Disease Control and Prevention (CDC), stroke is the third leading cause of death in the United States as of 2008, being responsible for about 160,000 deaths each year. About 700,000

Americans have strokes each year, 500,000 for the first time and 200,000 having a second or third stroke. The total cost of stroke to the American economy each year is about $43 billion.

About 50,000 Americans have a TIA in an average year; of this group, 35 percent will have a severe stroke at some point in the future.

Strokes can affect people in any age group; however, the risk increases sharply in people over fifty-five years of age. Seventy-five percent of all strokes occur in people over sixty-four. Men are 1.25 times more likely to have strokes than women; however, women are more likely to die of stroke because they are usually older when they have their first stroke.

African Americans have an increased risk of stroke compared to other racial and ethnic groups in the United States, and they are also more likely to suffer a stroke at younger ages. African Americans between the ages of forty-five and fifty-five die from stroke 4–5 times more often that Caucasians in the same age group.

First Aid for Stroke

The most important first step is to call for emergency help at once. Stroke is a medical emergency; the sooner the person is evaluated and treated, the better their chances of recovery. The drug presently considered most useful in treating stroke must be given within three hours of the attack to be effective.

Additional measures that can be taken while waiting for the emergency team:

• If the person stops breathing, give them mouth-to-mouth resuscitation.
• If they are vomiting, tilt their head to one side to prevent them from swallowing the material.
• Do not give them anything to eat or drink.

Risk factors for stroke include:

• Hypertension (high blood pressure). This is the most important single risk factor for stroke.
• High blood cholesterol levels.
• Being over age fifty-five.
• A family history of stroke, TIA, or heart attack.
• Diabetes.
• Smoking. Smoking doubles a person's risk of ischemic stroke.
• Personal history of previous stroke or TIA.
• Obesity.
• Heavy use of cocaine.
• Irregular heart rhythm.
• Heavy drinking. Alcohol consumption raises a person's blood pressure.
• Use of birth control pills or hormone replacement therapy.

Causes and Symptoms

Stroke is caused by a loss of blood supply to the brain resulting either from a clot blocking an artery or from bleeding into or around the brain. Ischemic stroke can result from two types of clots. The first is an embolus, which is a free-floating clot produced in the heart or somewhere else in the body that travels to a blood vessel in the brain. The second type of clot is formed within an artery in the head or neck and grows there until it is large enough to block the artery. Atherosclerosis, a disease of the blood vessels in which fatty deposits build up along the walls of the vessels, is a common cause of this type of clot.

Hemorrhagic stroke can occur when an aneurysm—a weak spot in the wall of an artery—suddenly bursts. High blood pressure is the most common cause of this type of hemorrhagic stroke. Hemorrhagic stroke can also occur when the walls of an artery become thin and brittle; they can then break and leak blood into the brain. Hemorrhagic stroke can take one of two forms: the blood can leak directly into brain tissue from an artery in the brain, or it can leak from an artery near the surface of the brain into the space between the skull and the membranes covering the brain.

The major symptoms of stroke have already been described. Other symptoms that some patients experience include drooling, uncontrollable eye movements, personality or mood changes, drowsiness, loss of memory, or loss of consciousness.

Diagnosis

The diagnosis of stroke includes taking the patient's history and obtaining an account of the patient's symptoms, followed by a complete physical and a neurological examination to rule out the possibility that the patient's symptoms are being caused by a brain tumor. The neurologist may use the National Institutes of Health Stroke Scale (NIHSS), which is a checklist that allows the doctor to record the patient's level of consciousness; visual function; ability to move; ability to feel sensations; ability to move the facial muscles; and ability to talk. Other tests include:

• Blood tests. These can reveal the existence of blood disorders that increase a person's risk of stroke.
• Computed tomography (CT) scan. This type of imaging test is one of the first tests given to a patient suspected of having a stroke. It

• helps the doctor determine the cause of the stroke and the extent of brain injury.
• Magnetic resonance imaging (MRI). This imaging test is useful in pinpointing the location of small or deep brain injuries.
• Electroencephalogram (EEG). This test measures the brain's electrical activity.
• Blood flow tests. These are done to detect the location and size of any blockages in the blood vessels. One type of blood flow test uses ultrasound to produce an image of the arteries in the neck leading into the brain. Another type of blood flow test, called angiography, uses a special dye injected into blood vessels that will show up on an x ray.
• Echocardiography. This type of test uses ultrasound to produce an image of the heart. It can be useful in determining whether an embolus from the heart caused the patient's stroke.

Treatment

Treatment of stroke depends on whether it is ischemic or hemorrhagic. Ischemic stroke is treated first with blood thinners, often aspirin or another drug known as warfarin. If the patient is seen by a specialized stroke team within three hours of the attack, he or she may be treated with a drug called tissue it is ischemic or activator or tPA. It is critical, however, to be sure that the patient has an ischemic rather than a hemorrhagic stroke, as blood-thinning drugs can make a hemorrhagic stroke worse.

Hemorrhagic stroke is treated by removing pooled blood from the brain and repairing damaged blood vessels. To prevent another hemorrhagic stroke, the surgeon may use a procedure called aneurysm clipping. In this procedure, the surgeon clamps the weak spot in the artery away from the rest of the blood vessel, which reduces the chances that it will burst and bleed.

After emergency treatment in the hospital, most stroke patients need long-term recovery and rehabilitation. The type and length of therapy depend on the amount of function the patient has lost; some need to relearn language skills, while others may need to relearn bowel and bladder control, swallowing, and movement or balance. Most patients need a combination of physical therapy, occupational therapy, speech therapy, and psychotherapy. It is common for stroke patients to feel depressed during rehabilitation or to have trouble controlling their feelings.

Prognosis

The prognosis of stroke depends on the person's age, the type and location of the stroke, and the amount of time elapsed between diagnosis and treatment. In general, patients with ischemic stroke have a better prognosis than those with hemorrhagic stroke. In one study in the Boston area, 19 percent of patients with ischemic stroke died within the first thirty days of the attack compared to 35 percent with hemorrhagic stroke.

About 10 percent of stroke patients recover enough function to live independently without help; another 50 percent can remain at home with outside assistance. The remaining 40 percent require long-term care in a nursing home.

Prevention

People cannot change some risk factors for stroke, such as race, age, sex, or family history, but they can control several other risk factors:

• They can quit smoking, drinking heavily, or using cocaine.
• They can keep their weight at a healthy level.
• They can exercise regularly, eat a healthy diet, and take medications for high blood pressure if they are diagnosed with it.
• They can take steps to lower their risk of diabetes or high blood cholesterol levels.
• They can lower the level of emotional stress in their life or learn to manage stress more effectively.
• They can get regular checkups for abnormal heart rhythms if they have been diagnosed with such problems.
• They can see their doctor at once if they have a TIA.

The Future

Stroke is a disorder that has attracted researchers from a number of different fields because its costs to individuals are still high and doctors are increasingly recognizing that many strokes are preventable. In addition, the aging of the American population means that the number of stroke patients is likely to increase over the next several decades. As of 2008, the National Institutes of Health was sponsoring 1,800 separate studies of stroke prevention and treatment, ranging from new medications to treat

ischemic stroke to investigations of the genetic factors that increase people's risk of stroke.

A recent innovation is the use of computer technology to allow stroke experts in one hospital to evaluate and diagnose a patient in another hospital that might not have a specialist available. Called Tele-Stroke, the network allows a patient to be evaluated for ischemic stroke within the three-hour time limit for the effective use of tPA.

SEE ALSO Coronary artery disease; Hypercholesterolemia; Hypertension; Sickle cell anemia; Smoking

WORDS TO KNOW

Aneurysm: A weak or thin spot on the wall of an artery.

Embolus: The medical term for a clot that forms in the heart and travels through the circulatory system to another part of the body.

Ischemia: Loss of blood supply to a tissue or organ resulting from the blockage of a blood vessel.

Thrombus: A blood clot that forms inside an intact blood vessel and remains there.

Transient ischemic attack (TIA): A brief stroke lasting from a few minutes to twenty-four hours. TIAs are sometimes called mini-strokes.

For more information

BOOKS

Edlow, Jonathan A. Stroke. Westport, CT: Greenwood Press, 2008.

Hreib, Kinan K. 100 Questions and Answers about Stroke: A Lahey Clinic Guide. Sudbury, MA: Jones and Bartlett Publishers, 2008.

McEwen, Mark. Change in the Weather: Life after Stroke. New York: Gotham Books, 2008.

PERIODICALS

Kolata, Gina. “Precious Hours, Then Lives, Lost in Stroke's Wake.” New York Times, December 22, 2007. Available online at http://health.nytimes.com/ref/health/healthguide/esn-stroke-ess.html (accessed on August 27, 2008).

WEB SITES

American Stroke Association. What Is Stroke? Available online at http://www.strokeassociation.org/presenter.jhtml?identifier=3030066 (accessed on August 27, 2008).

Centers for Disease Control and Prevention (CDC). Stroke Home Page. Available online at http://www.cdc.gov/stroke/(updated October 10, 2007; accessed on August 27, 2008).

eMedicine Health. Stroke. Available online at http://www.emedicinehealth.com/stroke/article_em.htm (accessed on August 27, 2008).

National Institute of Neurological Disorders and Stroke (NINDS). Stroke: Hope through Research. Available online at http://www.ninds.nih.gov/disorders/stroke/detail_stroke.htm (updated August 20, 2008; accessed on August 27, 2008).