What causes TIAs and is there any way to prevent them? Are they the same as strokes, but less severe, or are they completely different?

Q. What causes TIAs and is there any way to prevent them? Are they the same as strokes, but less severe, or are they completely different?

A. TIAs (transient ischemic attacks) are temporary interruption of circulation to part of the brain. They are manifested usually by a brief neurologic deficit such as weakness or numbness of part of an extremity, or blindness in one eye. The symptoms usually resolve within 20 minutes but may last up to 24 hours. If the symptoms last greater than 24 hours, then the patient has had a stroke. After a stroke, the symptoms may or may not get better.

The causes of TIA and stroke are the same; usually there is atherosclerosis (hardening of the arteries) that lead to a severe narrowing of an artery that supplies a given area of the brain. This embolus, which is the spread of a broken part of plaque from the wall of an artery, can break off and occlude an artery, or may be spread via the heart.

Risk factors for stroke include previous TIA or stroke, hypertension (high blood pressure), smoking, Diabetes, high cholesterol and family history of stroke and atrial fibrillation (a type of irregular heart rhythm).

Prevention is very important. Control of blood pressure, and cholesterol reduction are important. So is quitting smoking. For those with a history of TIA or stroke(which are strong risk factors for stroke), as well as those with other risk factors, antiplatelet therapy is very helpful to decrease risk of stroke.

Aspirin is the most commonly used, although there is a newer drug called Plavix which may be preferable in some patients. Also for patients with atrial fibrillation, Coumadin (a blood thinner) can be very effective in reducing risk. Bleeding is a potential complication of antiplatelet therapy and Coumadin, but in most cases the benefits of treatment outweigh the risks of bleeding. Surgery is also an option for patients who have severe narrowing of the carotid artery. This can be checked by ultrasound of the neck vessels.