Stroke is a brain injury caused by an interruption in blood flow. Brain tissue that does not get oxygen and nutrients from blood can die within minutes. The damage to the brain can cause a sudden loss in bodily functions. The types of function that are affected will depend on the part of the brain that is damaged.

There are two blood flow problems that cause a stroke. Strokes may be ischemic or hemorrhagic.

  • An ischemic stroke is caused by a blocked blood vessel. It is the most common cause of stroke.
  • A hemorrhagic stroke is caused by a ruptured blood vessel.

Hemorrhagic vs. Ischemic Stroke
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An ischemic stroke occurs when something stops the flow of blood. It may be a buildup or swelling of the walls of the blood vessels and/or something in the blood that becomes stuck in the blood vessel. A blockage in a small blood vessel will affect a smaller area of the brain. A blockage in larger blood vessels can block the flow of blood to several smaller blood vessels, leading to more brain damage.

The blockage may be the result of one or more of the following:

  • Atherosclerosis —a build-up of fatty substances along the inner lining of the artery that gradually decrease the area the blood can flow through
  • A blood clot that has traveled from other parts of the body such as the neck or heart
  • Inflammation of the blood vessels