Allison Maurizio, age 15, of Monroe, La., for her question:
WHAT CAUSES A STROKE?
A stroke is a serious medical condition that happens if the brain does not receive a proper amount of blood. There are three main causes: cerebral thrombosis, a cerebral hemorrhage or a cerebral embolism. Most strokes are a result of high blood pressure.
Every year more than 500,000 Americans suffer strokes and more than 200,000 die from them. Most stroke survivors temporary or permanent disabilities and are then in need of extensive medical care.
Cerebral thrombosis occurs when a blood clot forms in a major artery that carries blood to the brain. In most cases, the clot builds up in a blood vessel that has been narrowed by arteriosclerosis, which is a hardening of the arteries. People with high blood pressure are especially likely to develop arteriosclerosis.
A cerebral hemorrhage happens when an artery in the brain ruptures.
High blood pressure is usually at fault, but the rupture can also result from an aneurysm, a weak spot on an artery wall that can swell like a bubble until it bursts.
A cerebral embolism, like a cerebral thrombosis, involves a clot that blocks one of the major arteries of the brain. However, the clot forms in another part of the body. It then travels through the bloodstream until it clogs one of the arteries supplying the brain.
A person who suffers a stroke may first experience weakness and paralysis on one side of the body. Other symptoms may include difficulty in speaking or understanding language and vision problems, particularly blind spots.
In cerebral thrombosis, the symptoms may develop progressively during several hours or several days. In cerebral hemorrhage and cerebral embolism, the changes occur very rapidly. In either case, many victims eventually lose consciousness, and a large number of them die.
Recovery from a stroke depends on how much of the brain has been permanently damaged.
In a great many strokes, damage may occur only in one part of the brain that controls a certain activity, say walking. If enough of the area remains whole, the victim may be able to learn the activity again. Other parts of the brain also can be taught to take over some jobs previously performed by the damaged area.
Rehabilitation should start as soon as the patient regains consciousness. At first, the treatment consists of stretching contracted muscles and moving the arm and leg on the affected side of the body.
Controlling high blood pressure is the most effective way to prevent strokes. This can be done with medication and changes in diet.