A stroke is the sudden death of part of the brain usually when the flow of blood to the brain is interrupted. Without blood, to supply oxygen and nutrients and to remove waste products, the brain can die quickly. A stroke may be caused by a blood clot breaking free from elsewhere in the body and lodging in an artery supplying the brain, either in the brain itself or in the neck. Or, strokes may occur when a blood vessel bursts around or in the brain because the blood vessel wall is weak. Depending on the region of the brain affected, a stroke may cause paralysis, speech impairment, loss of memory and reasoning ability, coma or death. Stroke is a medical emergency requiring immediate treatment. Prompt treatment improves the chances of survival and increases the level of recovery in terms of limiting disability