Science / Cerebrovascular Accidents

Cerebrovascular Accidents

Autor:  Kill009  04 June 2011
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Running head: Cerebrovascular Accidents

Cerebrovascular Accidents

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Cerebrovascular Accidents

A cerebrovascular accident (CVA), also known as a stroke, occurs when the blood supply to the part of the brain is interrupted. Strokes are currently the third leading cause of death and leading cause of serious long term disability in the United States (National Stroke Foundation). Strokes affect people of any race, gender, or age group. Fortunately, up to 80% of strokes are preventable through lifestyle modifications. Conventional medicine has come a long way in the treatment of cerebrovascular accidents, but complementary and alternative modalities have been increasingly incorporated to improve the condition of the whole person.

Pathophysiology

A cerebrovascular accident begins with an infarction in the brain. An infarction is the process of tissue death resulting from the loss of the tissues blood supply. The loss of the blood supply robs the brain cells of oxygen and nutrients, as well as the cells ability to rid itself of waste material. A central area of necrosis develops as cells begin to die. The brain tissue surrounding the area of necrosis becomes inflamed. Brain function is immediately impaired in affected area of the brain. Cerebral edema and the area of infarct continue to increase over a 48 to 72 hour period. The brain tissue in the area of the infarct actually begins to liquefy, leaving a cavity within the brain.

Causes of Cerebrovascular Accidents

Ischemic

The most common type of ischemic stroke is caused by an atheroma, which is a gradual narrowing of the lumen of an artery. This type of CVA is also called a thrombotic stroke. This occurs as fatty deposits and cholesterol builds up in the blood vessel. This process usually occurs in the larger arteries such as the carotid. The second type of ischemic stroke is caused by an embolus. This type of stroke is caused by a sudden obstruction, usually because of a blood clot that has broken off from an atheroma. The clot travels through the blood stream until it lodges in a smaller blood vessel causing an interruption of the blood supply to the brain. These emboli usually originate from the left ventricle of the heart because of left sided congestive heart failure or prosthetic valves. Although most emboli are blood clots, an embolus can be caused by infection, air, tumor, or fat.

Hemorrhagic stroke

Hemorrhagic strokes are much more severe. This type of ...