A stroke occurs when blood supply to the brain is interrupted or there is bleeding in the brain. Within minutes, brain cells begin to die. It is urgent to get emergency care at the first sign of a stroke. Early treatment saves many lives and reduces the effects of stroke.
Most strokes occur when a blood vessel in the brain is blocked and blood flow stops. This type of stroke is called an ischemic (iss-KEYmik) stroke. The blockage may be caused by a blood clot, and severe brain swelling may result. Life-saving surgery may be necessary to remove the clot and the brain tissue that has died from lack of oxygen.