Stroke

Strokes, also called cerebrovascular accidents (CVAs), are an important cause of death and disability around the world, being in the top three causes of death and one of the leading causes of disability in the United States. Strokes can be of two types—ischemic or hemorrhagic—but both cause a sudden neurologic change, such as weakness, blindness, confusion, or numbness due to injury to brain cells. Historically, no cure for stroke could be given, but in recent years, several methods of treating acute stroke have been developed.

A CVA is caused when brain cells are injured, either by cutting off the blood supply to those cells or by bleeding into the brain. The first type is called an ischemic stroke and is the most common, accounting for 85 to 90 percent of strokes. It is caused by occlusion of a blood vessel supplying the brain. Several medical conditions can cause these clots, for instance, certain heart problems (such as atrial fibrillation, heart valve problems, or even heart attacks) may cause tiny blood clots to be made in the heart and travel to the brain, or cholesterol deposits in blood vessels within the brain may occlude the vessel. Diseases in which the blood is more prone to clot, such as certain cancers or hereditary blood clotting disorders, may also cause ischemic strokes. Hemorrhagic strokes are caused by bleeding into the brain, usually caused by damage to a blood vessel. These types of strokes are less common, comprising only 10 to 15 percent of strokes, but are more dangerous. They are most often caused by high blood pressure. The continual high pressure in the blood vessels leads to vessel weakening and possibly hemorrhage. These two types of strokes have similar symptoms but very different treatments, so a computed tomography (CT) scan of the head is needed to determine which type has occurred.

Symptoms of both types of stroke include sudden weakness, inability to speak or read, numbness, or blindness. Usually, these symptoms occur on only one side of the body at a time. Symptoms can wax and wane, leading many patients to deny their severity and delay getting treatment.

Treatment for ischemic stroke is a relatively new development and includes giving special medicine called thrombolytics or clot busters to destroy the clot. These medicines can be dangerous to use, so they can only be given by specially trained doctors and nurses to patients who meet certain criteria. In addition, these medicines only work if they are used within three hours after the first stroke symptoms have appeared.

Many new treatments are currently being developed for ischemic stroke, involving direct removal of the clot by a mechanical device or by targeted administration of clot-busting drugs. Hemorrhagic strokes are mainly treated by controlling blood pressure and correcting any bleeding abnormalities. Occasionally, surgery is done to take out the blood accumulation. Clot buster drugs are extremely dangerous in this form of stroke and so cannot be used. After a stroke has occurred, two other important aspects of treatment include physical therapy to maximize recovery of any lost abilities, and also prevention of future strokes.

...