Stroke is a brain attack and the third largest cause of death in America, after diseases of the heart and cancer. While elderly people account for the vast majority of stroke deaths, stroke ranks third as a cause of death among middle-aged people.
Despite these statistics, there is good news. The age-adjusted death rate for stroke in the United States has been steadily declining, dropping from 89 per 100,000 population in 1950 to 28 in 1990. The rate declined about 1 percent a year until 1972. After that, it started dropping about 5 percent a year.
Improvements in medical care for stroke survivors and better control of high blood pressure have played a part in this decline.
A stroke is a form of cardiovascular disease. It affects the arteries or veins and stops the flow of blood bringing oxygen and nutrients to the brain. A stroke occurs when one of these blood vessels burst or becomes clogged. When this happens, part of the brain does not receive the flow of blood it needs and starts to die.
When brain cells die during a stroke, abilities controlled by that area of the brain are lost. These abilities include speech, movement and memory. How a stroke patient is affected depends on where the stroke occurs in the brain and how much the brain is damaged.
For example, someone who has a small stroke may experience only minor problems such as weakness of an arm or leg. People who have larger strokes may be paralyzed on one side or lose their ability to speak. Some people recover completely from strokes, but more than two-thirds of survivors will have some type of disability.
One of the most common types of brain attack is cerebral thrombosis.
This occurs when a blood clot forms in a vessel in the brain. Blood clots form most often in arteries injured by atherosclerosis. This is a disease condition in which fatty deposits build up in the inner walls of arteries.
Another type of brain attack is a cerebral embolism. It occurs when a clot or other particle gets stuck in an artery leading to the brain or in the brain itself. Such clots are carried by the bloodstream and most often come from diseased areas in the heart.
Not all brain attacks are caused by blood clots. Some strokes occur because a blood vessel on the brain ruptures and bleeds between the brain and skull. This is called a subarachnoid hemorrhage. Another type of stroke is a cerebral hemorrhage. This type of brain attack occurs when a defective artery in the brain bursts, flooding the surrounding tissue with blood. Cerebral hemorrhage is often associated with high blood pressure.
Brain attacks can happen at any time. On average, someone suffers a stroke in the United States every 53 seconds. Every 3.3 minutes, someone dies of one.