Transient ischemic attack
Transient ischemic attacks are commonly referred to as TIA’s or mini-strokes, and are similar in symptoms to strokes. TIA’s are generally short-lived, lasting no more than a few minutes and usually producing no permanent damage. Since approximately one in three people who have a TIA will suffer a full-blown stroke, with nearly half of them occurring in the year following the TIA, it is wise to consider a TIA a warning and take steps to improve any risk factors contributing to the possibility.
Definition & Facts
A TIA has the same origins as that of an ischemic stroke (the most common type of stroke), but while both involve a blood clot blocking the blood supply to part of your brain, in a TIA, the blockage only occurs for a short time and causes little or no permanent damage. A TIA is considered a mini-stroke caused by the temporary lack of an adequate supply of oxygen and blood to the brain, which can be caused by the narrowing of the carotid arteries. TIA's usually last from two minutes to a half-hour, and can create dizziness, vision problems, speech problems, and a feeling of weakness.
Symptoms & Complaints
The main cause of TIA’s is atherosclerosis (the buildup of plaques that contain fatty deposits) in either an artery or a branch of an artery; this build-up can cut off the supply of oxygen and nutrients to the brain. Plaques can also lead to the development of a clot that moves to an artery supplying blood and oxygen from another part of the body, usually from the heart.
There are a number of risk factors associated with TIA. They include: family history of TIA’s or strokes, being older than 55 or having a prior history of TIA’s. While more than half of all stroke deaths occur in women, men are at a slightly greater risk of having either a TIA or a stroke. African Americans have a greater risk of TIA’s and strokes. Strokes can also be complications of Sickle-cell disease.
Additional risk factors include:
- High blood pressure and high cholesterol, both of which can contribute to the development of narrowing or blockages in the arteries.
- Cardiovascular disease such as a congenital heart defect, heart failure, or (more rarely) a heart infection
- Untreated diabetes which helps build up the fatty deposits that narrow the arteries
- PAD (peripheral artery disease) that occurs when the blood vessels carrying blood to your limbs become clogged
- Being overweight, meaning a BMI of 25 or over and a waist that is more than 35 inches for females and 40 inches for males.
- Another contributor can be high levels of the amino acid, homocysteine, which can be the cause of arteries thickening and scarring, making them more susceptible to clotting.
Diagnosis & Tests
A doctor may diagnose a TIA by the patient's description of the event, since the attacks are short in time and usually gone by the time a physician is involved. The doctor will administer a physical examination including blood tests for high cholesterol, blood pressure, and diabetes. There may be platelet or cholesterol fragments in the retina's blood vessels that are visible to the doctor during an exam. Other diagnostic tools may include:
- A CT scan, which uses X-rays to create a 3-D look at the brain
- A CTA scan or CT angiogram, another noninvasive technique that can help the doctor evaluate the arteries in the brain and neck
- An MRI that creates a view of the brain using a strong magnetic field
- A carotid ultrasound that uses a transducer (wand) to produce images that show clotting or narrowing in the carotid arteries
- An echocardiogram that also uses a wand-like instrument to create an image of the heart
- The less common use of arteriography which uses injected dye and a catheter inserted through a small incision in the groin area to provide images of arteries in the brain
Treatment & Therapy
In the case of TIA’s, medications are used to help prevent strokes that might otherwise occur later. Two types of medications are used. One is anti-platelet drugs that make blood platelets less likely to become sticky and form clots; this class of drugs includes aspirin as well as prescription medications.
The other class of drugs is anti-coagulants (often called blood-thinners) which help prevent blood from clotting. Surgery called carotid endarterectomy clears the carotid arteries of plaques. Angioplasty involves using a balloon type device to open the clogged artery, after which a stent (small wire tube) may be placed into the artery to keep it open.
Prevention & Prophylaxis
Other changes include getting 30 minutes of exercise at a moderate level each day; reducing fat and salt intake; reducing alcohol consumption to two drinks a day for a man and one drink a day for a woman. Illegal drugs like cocaine can increase the risk of having a TIA or stroke, and thus should be avoided. Birth control and other hormone therapies may increase the risk of stroke, and thus need to be discussed with one's doctor.