Transient Ischemic Attack: An Introduction
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.
Transient Ischemic Attack Causes
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 (s
ee 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).
Symptoms of a Transient Ischemic Attack
Transient ischemic attack symptoms, which usually occur suddenly, are similar to those of
stroke but do not last as long. Most symptoms of a transient ischemic attack disappear within an hour, although they may persist for up to 24 hours.
Transient ischemic attack symptoms can include:
- Numbness or weakness in the face, arm, or leg (especially on one side of the body)
- Confusion
- Difficulty talking or understanding speech
- Trouble seeing in one or both eyes
- Difficulty walking, dizziness, or loss of balance and coordination.
Less common symptoms of a transient ischemic attack include sudden nausea, vomiting, brief loss of consciousness, or decreased consciousness (such as fainting and convulsions).
If you suspect you or someone you know is experiencing one or more of these symptoms of
TIA, do not wait for the symptoms to worsen or improve. Call 911 immediately. It is impossible for you to know whether these are transient ischemic symptoms or something more serious (such as
stroke symptoms).
(Click TIA Symptoms for more information about the symptoms of transient ischemic attacks.)
Diagnosing a Transient Ischemic Attack
As part of diagnosing a transient ischemic attack, the healthcare provider will ask a number of questions (concerning the patient's medical history, symptoms, etc.) and perform a physical exam. If the healthcare provider believes that a person has had a transient ischemic attack, he or she may order additional tests to search for possible causes of a TIA or to rule out other conditions that can cause symptoms that mimic a TIA.
(Click TIA Diagnosis for more information on diagnosing a TIA, including details about specific diagnostic tests that doctors may recommend.)
Treatment for a Transient Ischemic Attack
Because there is no way to tell whether symptoms are caused by a transient ischemic attack or an acute
stroke, assume that all stroke-like symptoms signal an emergency -- do not wait to see if they go away. A prompt evaluation is necessary to identify the cause of the transient ischemic attack and to determine appropriate therapy.
Depending on a patient's medical history and the results of a medical examination, the doctor may recommend drug therapy or surgery to reduce the risk of stroke in people who have had a transient ischemic attack. The use of antiplatelet medications, particularly aspirin, is a standard treatment for patients at risk for stroke. Doctors may prescribe anticoagulants, such as warfarin (Coumadin
®) for people with
atrial fibrillation (irregular beating of the heart).
(Click TIA Treatment for more information on these treatment options for a transient ischemic attack.)
Transient Ischemic Attack: Prognosis
A transient ischemic attack is often a warning sign that a person is at risk for a serious and debilitating stroke. About one-third of people who have a transient ischemic attack will have an acute stroke some time in the future. Many strokes can be prevented by heeding the warning sign of a transient ischemic attack and treating underlying risk factors.
The most important treatable risk factors that are linked to a transient ischemic attack and stroke are:
Medical help is available to reduce and eliminate these factors.
Lifestyle changes such as eating a balanced diet, maintaining healthy weight, exercising, and enrolling in smoking and alcohol cessation programs can also reduce these factors.
(Click TIA Prevention to learn more about preventing a transient ischemic attack. Click TIA Risk Factors to learn more about risk factors for a TIA that you can control along with those that you cannot control.)
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