Strokes, or brain attacks, are a major cause of death and permanent disability. They occur when blood flow to a region of the brain is obstructed and may result in death of brain tissue.

Stroke Image - Masterfile

There are two main types of stroke: ischemic and hemorrhagic. Ischemic stroke is caused by blockage in an artery that supplies blood to the brain, resulting in a deficiency in blood flow (ischemia). Hemorrhagic stroke is caused by the bleeding of ruptured blood vessels (hemorrhage) in the brain.

During ischemic stroke, diminished blood flow initiates a series of events (called ischemic cascade) that may result in additional, delayed damage to brain cells. Early medical intervention can halt this process and reduce the risk for irreversible complications.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 02 Jan 2000

Last Modified: 05 Mar 2015