A stroke occurs when the blood supply to a part of your brain is
interrupted or severely reduced, depriving brain tissue of oxygen and
nutrients. Within a few minutes, brain cells begin to die. Stroke
is a medical emergency, and prompt treatment of a stroke is crucial.
Early treatment can minimize damage to your brain and potential stroke
complications.
The good news is that strokes can be treated, and
many fewer Americans now die of strokes than was the case 20 or 30
years ago. Improvement in the control of major risk factors for stroke
— high blood pressure, smoking and high cholesterol — is likely
responsible for the decline.


Mayo Clinic July 3, 2008