Stroke Summary
A stroke results from impaired oxygen delivery to brain cells via the bloodstream. A stroke is also referred to as a CVA, or cerebrovascular incident. Symptoms of stroke include: sudden numbness or weakness of the face, arm or leg. Sudden confusion, trouble speaking or understanding. Sudden trouble seeing in one or both eyes, sudden trouble walking, dizziness, or loss of balance, and/or sudden severe headache with no known cause. A TIA, or transient ischemic attack is a short-lived temporary impairment of the brain caused by loss of blood supply. Stroke is a medical emergency.
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Stroke facts

  • Stroke is the sudden death of brain cells due to lack of oxygen.
  • Stroke is caused by the blockage of blood flow or rupture of an artery to or in the brain.
  • Sudden tingling, weakness, or paralysis on one side of the body or difficulty with balance, speaking, swallowing, or vision can be a symptom of a stroke.
  • Any person suspected of having a stroke or TIA should present for emergency care immediately.
  • Clot-busting drugs like tPA can be used to reverse a stroke, but the time frame for their use is very narrow. Patients need to present for care as soon as possible so that tPA therapy can be considered.
  • Surgical treatments are used infrequently under special circumstances.
  • Stroke prevention involves minimizing risk factors, such as controlling high blood pressure, elevated cholesterol, tobacco abuse, and diabetes.

What is a stroke?

Brain cell function requires a constant delivery of oxygen and glucose from the bloodstream. A stroke occurs when blood supply to part of the brain is disrupted, leading to inadequate oxygen supply and causing brain cells to die. Blood flow can be compromised in a variety of ways. Stroke is also referred to as cerebrovascular accident (CVA).

Blockage of an artery

  • Narrowing of the small arteries within the brain can cause a lacunar stroke (lacune means "empty space"). Blockage of a single arteriole can affect a tiny area of brain causing that tissue to die (infarct).
  • Hardening of the arteries (atherosclerosis) leading to the brain. There are four major blood vessels that supply the brain with blood. The anterior circulation of the brain's two cerebral cortices controls most motor activity, sensation, thought, speech, and emotion is supplied by the two carotid arteries. The posterior circulation, which supplies the brainstem and the cerebellum, controlling the automatic parts of brain function and coordination, is supplied by the two vertebrobasilar arteries.

If these main arteries become narrowed as a result of atherosclerosis, plaque or cholesterol debris can break off and float downstream, clogging the blood supply to a part of the brain. As opposed to lacunar strokes, larger parts of the brain can lose blood supply, and this may produce more symptoms, with loss of brain and body function, more than seen with a lacunar stroke.

  • Embolism to the brain from the heart. In some instances a thrombus or blood clot can form within the heart and the potential exists for them to break off and travel (embolize) to the arteries in the brain and cause a stroke. Atrial fibrillation, an irregular heart rhythm, is the most common cause of thrombus formation.

Rupture of an artery (hemorrhage)

  • Cerebral hemorrhage (bleeding within the brain substance). The most common reason to have bleeding within the brain is uncontrolled high blood pressure. Other situations include aneurysms that leak or rupture or arteriovenous malformations (AVM) in which there is an abnormal collection of blood vessels that are fragile and can bleed.
Medically Reviewed by a Doctor on 4/10/2013

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Stroke Symptoms

What are stroke risk factors?

The risk factors for stroke include high blood pressure, diabetes, cigarette smoking , a family history of stroke, heart disease, prior history of stroke, alcohol abuse, and increasing age. Learning to recognize the signs and symptoms of a stroke is vital in order to ensure that the victim receives immediate medical attention. According to The U.S. National Institute of Neurological Disorders and Stroke, these are the five major signs of stroke:

    • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body. The loss of voluntary movement and/or sensation may be complete or partial. There may also be an associated tingling sensation in the affected area.
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