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Transient ischemic attack (TIA)
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| Transient ischemic attack (TIA) |
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Definition:
A transient ischemic attack is a "mini-stroke" caused by temporary disturbance of blood supply to an area of the brain, resulting in a sudden, brief decrease in brain function. (It lasts less than 24 hours, usually less than one hour) . Alternative Names:
Mini stroke; TIA; Little stroke Text Continues Below
Causes, incidence, and risk factors:
A transient ischemic attack (TIA) is caused by an interruption of blood flow to brain cells. If the symptoms resolve completely in under 24 hours, this is called a TIA or "mini stroke." If the symptoms do not resolve, the event is called a stroke. A brief interruption to the blood flow can cause a decrease in brain function (neurologic deficit). Symptoms vary with the area of the brain affected and may include changes in vision, speech or comprehension, vertigo, decreased movement or sensation in a part of the body, or changes in the level of consciousness. If the blood flow is decreased for a sufficient period, brain cells in the area die (infarct), causing permanent damage to that area of the brain or even death. The loss of blood circulation to the brain can be caused by the following: - narrowing of a blood vessel
- blood clotting within an artery of the brain
- blood clot traveling to the brain from somewhere else in the body (e.g., heart)
- a blood disease, cancer, and others
- inflammation of blood vessels
- injury to blood vessels
In a TIA, the blood supply is only temporarily blocked. For example, a blood clot may dissolve and allow blood to flow normally again. Atherosclerosis ("hardening of the arteries") is a condition where fatty deposits occur on the inner lining of the arteries, which dramatically increases the risk for both TIAs and stroke. Atherosclerotic plaque is formed when damage occurs to the lining of an artery. Platelets clump around the area of injury as a normal part of the clotting and healing process.
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