A
transient ischemic attack (TIA for short) starts just like a
stroke but then resolves, leaving no noticeable symptoms or deficits. This is why a TIA is sometimes called a
mini-stroke. The occurrence of a TIA is a warning that the person is at risk for a stroke, which is usually more serious and debilitating. Of the approximately 50,000 Americans who have a TIA each year, about one-third will have an acute stroke sometime in the future.
A TIA is caused by a temporary lack of oxygen- or nutrient-rich blood to a part of the brain. This lack of blood supply occurs because a blood vessel becomes severely narrowed or blocked.
There are several ways in which a blood vessel in the brain may become severely narrowed or blocked. The two most common are an embolism and 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 third way in which a blood vessel can become narrowed or blocked involves stenosis. Stenosis is severe narrowing of an artery in or leading to the brain. It is most often caused by
plaque buildup.
Keep in mind that the causes of mini-strokes are the same as those of
ischemic strokes (
see Stroke Causes). The only difference between the two involves timing. By definition, a stroke produces symptoms that last for at least 24 hours. A mini-stroke causes symptoms that improve after a shorter period of time (usually less than 30 minutes).
Risk factors are conditions or behaviors that increase your chances of getting a certain disease. Some TIA risk factors can be treated or controlled and some cannot. The more risk factors you have, the greater your risk of having a TIA. That's because risk factors tend to "gang up" and worsen each other's effects. Finally, the higher your level of each risk factor, the greater your risk of having a TIA.
TIA risk factors that you cannot change include:
- Age (risk tends to increase with age)
- Being male
- Being African American
- Having a family history of TIA
- Having had a TIA or heart attack in the past.
Some of the most important treatable or controllable risk factors for TIA are:
The symptoms of a TIA are distinct because they happen quickly. However, the specific symptoms will vary based on which part of the brain is affected. TIA symptoms can include:
- Sudden confusion
- Sudden difficulty speaking or understanding speech
- Sudden trouble seeing in one or both eyes (such as double vision, blurred vision, or blindness)
- Sudden trouble walking or dizziness
- Sudden loss of balance or coordination
- Sudden severe headache with no known cause
- Sudden numbness or weakness of the face, arm, or leg (especially on one side of the body).
Other possible symptoms of a TIA that are less common, but still important, are sudden nausea, vomiting, and brief loss of consciousness or decreased consciousness (such as fainting).
If you suspect you or someone else is experiencing one or more of these symptoms of TIA, call 911 immediately. Do not wait for the symptoms to worsen or improve. It is impossible for you to know whether these are TIA symptoms or something more serious (such as a
stroke).
As part of diagnosing a TIA the healthcare provider will probably ask a number of questions (such as those concerning the patient's medical history and symptoms) and perform a physical exam. If the healthcare provider believes that a person has had a TIA, he or she may order additional tests to look for possible causes of a TIA or to rule out other conditions that can cause symptoms similar to those of a TIA.
These tests may include:
- Blood tests (such as tests looking for high cholesterol or diabetes)
- Computed tomography scan (also known as a CAT scan or CT scan)
- Magnetic resonance imaging (MRI)
- Carotid Doppler ultrasound
- Carotid arteriography
- Cerebral angiography (also known as a cerebral angiogram, cerebral arteriogram, or digital subtraction angiography)
- Magnetic resonance angiogram (MRA) or functional magnetic resonance imaging (fMRI)
- Transcranial Doppler
- Electrocardiogram (EKG)
- Echocardiogram
- Lumbar puncture
- Electroencephalography (EEG).
Research has shown that people who get treatment for a TIA can significantly decrease their chances for a
stroke.
Treatment for a TIA typically involves the following:
- Lifestyle changes, such as quitting smoking, changing your diet, or increasing your physical activity
- Medications used to help blood from clotting or control TIA risk factors, such as high blood pressure or atrial fibrillation
- A surgery or procedure to help decrease the chances of another transient ischemic attack.
(Click TIA Treatment for more information on these treatment options for a TIA.)
A person can lower his or her chances of having a TIA by understanding the risk factors for it, and then using that knowledge to make good decisions to control any TIA risk factors he or she has.
Why is TIA prevention important? Because one-third of people who have a TIA will go onto have a
stroke within five years. Through effective treatment of TIA risk factors, this risk can be significantly decreased.
The steps for effective TIA prevention involve:
- Knowing your TIA risk factors
- Monitoring your health and making lifestyle changes
- Possibly taking medication or having a procedure
- Knowing signs of a TIA or stroke (see Stroke Symptoms).
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