Patti Oicanich, 12, of Ribbing, Minn., for her question:
WHAT CAUSES A STROKE?
When a person suffers a stroke, he may experience paralysis or weakness on one side of his body. He may also find it difficult to speak or understand language, and discover blind spots in his vision. The symptoms may worsen progressively during several hours or days, or the changes may occur very rapidly, depending on the type of stroke.
A stroke is a serious medical condition that happens if the brain does not receive an adequate supply of blood. A regular supply of oxygen and nutrients is needed by the brain, and when the flow is interrupted for as short a period as three to 10 minutes, permanent damage can result.
Doctors say that most strokes are caused by either a cerebral thrombosis, a cerebral hemorrhage or a cerebral embolism.
In cerebral thrombosis, a blood clot forms in one of the major arteries that carries blood to the brain. This type of problem often builds up slowly as a person's arteries narrow by arteriosclerosis, or hardening of the arteries. Many who develop arteriosclerosis are those who have high blood pressure.
Often people who suffer cerebral thrombosis are those who have had previous incipient strokes. These are attacks that result in the momentary reduction of blood flowing through narrow arteries. A person may feel dizziness, tingling, weakness, slurred speech and visual problems in one eye. The symptoms sometimes last only 30 minutes or so and then disappear.
Cerebral hemorrhages occur when arteries in the brain rupture. Blood pressure that is too high is often the cause, or it can be the result of an artery's wall having an aneurysm a weak spot that can swell like a bubble until it bursts.
A cerebral embolism is like a cerebral thrombosis in that it involves a clot that blocks a major artery of the brain. The clot, however, forms in another part of the body and travels through the bloodstream until it clogs one of the arteries that supplies the brain.
Every year more than half a million Americans suffer from strokes. More than 200,000 of the attacks prove to be fatal, but 60 percent of the victims recover with medical care.
Recovery from a stroke depends on how much of the brain received permanent damage when the blood was cut off. Rehabilitation by medical people should begin as soon as possible.
High blood pressure, called hypertension, is probably the basic cause of most strokes. Controlling this condition can be an effective way of preventing strokes. Doctors recommend various medicines and diets to help those with high blood pressure.
Surgery has also been used to prevent major strokes by those who have suffered from incipient strokes. Carotid arteries in the neck can be cleaned of material that is clogging them if they become too narrow.