A medical emergency in which bleeding occurs in the brain, also known as a cerebral accident or cerebrovascular accident. A stroke happens when there is a blockage of blood or the rupture of a blood vessel responsible for supplying blood to the brain, which can result in impaired brain function or death. People who are at risk of experiencing a stroke are those of older age or who have certain disorders such as atrial fibrillation, carotid artery disease, heart failure, hyperlipidemia, hypertension, a history of myocardial infarction or diabetes mellitus.