A stroke is a medical condition in which poor blood flow to the brain results in cell death. There are two main types of strokes: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both types of strokes can cause permanent brain damage and even death.
Ischemic strokes are by far the most common type of stroke, accounting for 87% of all cases. They occur when a blood clot blocks one or more arteries that supply blood to the brain. The most common cause of an ischemic stroke is atherosclerosis, a buildup of plaque in the arteries. Other causes include heart disease, embolism (a clot that breaks loose and travels through the bloodstream), and drug use (such as cocaine).
Hemorrhagic strokes make up about 13% of all cases. They occur when a blood vessel ruptures and bleeds into the brain. The most common type of hemorrhagic stroke is an intracerebral hemorrhage, in which bleeding occurs within the brain tissue itself. Other types include subarachnoid hemorrhages (bleeding around the membrane that covers the brain) and cavernous sinus thrombosis (a blockage of veins draining blood from the brain).
Both ischemic and hemorrhagic strokes can lead to disability and even death. In fact,stroke is currently the fifth leading causeof death in developed countries such as the United Statesand Canadaand a major causeof disability worldwide. However, with early diagnosisand proper treatment, many people who experience a strokemade complete recoveries with minimal or no long-term effects.