Transient Ischemic Attack
A transient ischemic attack (TIA) is a "mini-stroke" that usually lasts only a few minutes and occurs when the blood supply to part of the brain is briefly interrupted. The symptoms of a TIA are similar to those of a stroke and may include confusion, trouble seeing, and dizziness. People who have had a TIA are at an increased risk of having a stroke.
A transient ischemic attack (also known as a TIA or mini-stroke) is a sudden event that normally lasts only a few minutes. A TIA occurs when there is a brief interruption in the blood supply to part of the brain. A transient ischemic attack does not cause brain damage, but it is an important warning sign that a person is at risk of having a stroke.
If you have a transient ischemic attack, you should seek medical care right away to prevent a full stroke. Of the approximately 50,000 Americans who have a TIA each year, about one-third will have an acute stroke sometime in the future.
What Causes It?
A transient ischemic attack results from a temporary lack of oxygen- or nutrient-rich blood to a part of the brain. This lack of blood supply occurs when a blood vessel becomes severely narrowed or blocked.
There are a several ways in which a blood vessel in the brain may become severely narrowed or blocked. Most commonly, a transient ischemic attack is the result of an embolism or thrombosis. An embolism occurs when a blood clot or other tissue from another part of the body (such as the heart) moves through the blood into the neck or brain.
Thrombosis occurs when a blood clot (known as a thrombus) forms within a blood vessel of the brain or neck. Unlike an embolism, with thrombosis the blood clot does not break free.
A blood vessel in or leading to the brain can become narrowed or blocked as a result of stenosis. Stenosis is severe narrowing of an artery that is most often caused by a plaque buildup.
These possible causes of a transient ischemic attack are the same as for an ischemic stroke (see Stroke Causes). The only difference between a TIA and stroke involves duration of the episode. By definition, a stroke produces symptoms that last for at least 24 hours. A transient ischemic attack results in symptoms that improve after a shorter period of time (usually within 30 minutes).
(Click Causes of Transient Ischemic Attacks for more information on these specific causes.)