There are two main types of stroke:

• Ischemic strokes:
• Caused by blood clots that block an artery in the brain
• The blood clot may form within the vessel inside the brain or become lodged in a brain artery, after forming somewhere else in the body and then travelling (embolize) to the brain.
• Hemorrhagic strokes:
• Caused by bleeding from an artery in the brain

Brain cells are very sensitive to a lack of blood flow. Without oxygen and glucose from the bloodstream, they begin to die within minutes.