Posterior Cerebral Artery Infarction Health Channel

Definition

A stroke is an interruption of the blood supply to any part of the brain. A stroke is sometimes called a "brain attack."

See also: Arteriovenous malformation (AVM)

Alternative Names

Cerebrovascular disease; CVA; Cerebral infarction; Cerebral hemorrhage; Ischemic stroke; Stroke - ischemic; Cerebrovascular accident

Causes, incidence, and risk factors

A stroke happens when blood flow to a part of the brain is interrupted because a blood vessel in the brain is blocked or bursts open.

If blood flow is stopped for longer than a few seconds, the brain cannot get blood and oxygen. Brain cells can die, causing permanent damage.

There are two major types of stroke: ischemic stroke and hemorrhagic stroke.

ISCHEMIC STROKE

Ischemic stroke occurs when a blood vessel that supplies blood to the brain is blocked by a blood clot. This may happen in two ways:

• A clot may form in an artery that is already very narrow. This is called a thrombus. If it completely blocks the artery, it is called a thrombotic stroke.
• A clot may break off from somewhere in the body and travel up to the brain to block a smaller artery. This is called an embolism. It causes an embolic stroke.

Ischemic strokes may result from clogged arteries, a condition called atherosclerosis. (See: Stroke secondary to atherosclerosis) This may affect the arteries within the brain or the arteries in the neck that carry blood to the brain.