Strokes involving the right side of the brain, for example, produce weakness of the left side of the body. Some affect speech. Around 80% of strokes are ischaemic strokes, caused by a blood clot blocking an artery transporting blood to the brain. Transient ischaemic attacks, or ‘mini-strokes’, with effects lasting only briefly (less than 24 hours), require investigation to try to forestall the possibility of a subsequent full-blown stroke.

The disease of the arteries that predisposes to stroke is atherosclerosis. High blood pressure (hypertension) is also a precipitating factor - a worldwide study in 1995 estimated that high blood pressure before middle age gives a tenfold increase in the chance of having a stroke later in life.

Strokes can sometimes be prevented by surgery (as in the case of some aneurysms), or by use of anticoagulant drugs or vitamin E or daily aspirin to minimize the risk of stroke due to blood clots. According to the results of a US trial in 1995, the clot-buster drug tPA, if administered within three hours of a stroke, can cut the number of stroke victims experiencing lasting disability by 50%. The best predictor of strokes among older people may be an echogram (sonogram) of carotid arteries. According to a 1999 medical study, a diet rich in fruit and vegetables can lower the risk of strokes.

weblinks

American Heart Association

Brain Basics: Preventing Stroke