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Cause

Causes of ischemic stroke

An ischemic stroke is caused by a blood clot that blocks blood flow to the brain.

  • A blood clot can form in an artery that supplies blood to the brain.
    • Blood clots usually form in arteries damaged by plaque buildup, which is a process called atherosclerosis.
    • Long-term high blood pressure or diabetes may damage smaller blood vessels in the brain, causing a clot to form within the blood vessels and block blood flow.
  • A blood clot can form in another part of the body (often the heart) and travel through the bloodstream to the brain. For example, clots may form:

Low blood pressure may also cause an ischemic stroke, although this is less common. Low blood pressure results in reduced blood flow to the brain. It may be caused by narrowed or diseased arteries, a heart attack, a large loss of blood, or a severe infection.

Recommended Related to Stroke

Silent Stroke: What You Need to Know

Have you had a stroke? How could you tell? A stroke is a sudden stop of blood supply to part of the brain. Some people have strokes without ever knowing it. These so-called silent strokes either have no easy-to-recognize symptoms, or you don’t remember them. But they do cause permanent damage in your brain. If you've had more than one silent stroke, you may have thinking and memory problems. They can also lead to more severe strokes.

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Some surgeries (such as endarterectomy) or other procedures (such as carotid artery stenting) that are used to treat narrowed carotid arteries may cause a blood clot to break loose, resulting in a stroke.

Causes of hemorrhagic stroke

A hemorrhagic stroke is caused by bleeding in or around the brain.

  • Bleeding inside the brain itself (intracerebral hemorrhage, or ICH) may be a result of long-term high blood pressure.
  • Bleeding in the space around the brain (subarachnoid hemorrhage, or SAH) may be caused by a ruptured aneurysm or uncontrolled high blood pressure.

Other less common causes include head or neck injuries, certain diseases, and radiation treatment for cancer in the neck or brain.

WebMD Medical Reference from Healthwise

Last Updated: February 05, 2013
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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