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What is a stroke?

A stroke, or brain attack, happens when a blood vessel carrying oxygen and nutrients to the brain is blocked by a clot (ischemic stroke) or bursts (hemorrhagic stroke). When an artery is blocked, the brain can’t get the blood and oxygen it needs. Brain cells can die from the lack of blood and oxygen.

Ischemic strokes are the most common type. There are three types of blood vessel blockages in the brain or neck that cause ischemic strokes:

  1. Thrombosis: The formation of a clot within a blood vessel of the brain or neck.
  2. Embolism: The movement of a clot from another part of the body, such as the heart, to the neck or brain.
  3. Stenosis: A severe narrowing of an artery in or leading to the brain.

If a blood vessel bursts inside your brain, a hemorrhagic stroke can take place. Approximately 20 percent of all strokes are hemorrhagic strokes. Damage occurs either because of the blood that leaks into the brain or because the fluid increases pressure on the brain. This hurts your brain by pressing it against the skull or the brain stem.

A stroke may also occur because a brain aneurysm, or a weak area in the wall of an artery that supplies blood to the brain, ruptures.

Getting treatment as soon as a stroke happens can make a big difference in survival and recovery, but you must know the warning signs.

Nearly 80 percent of strokes are preventable. Learn more about stroke risk factors and preventing stroke » 

Page last updated: 9/11/2014 2:44:36 PM