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TIA - TRANSIENT ISCHAEMIC ATTACK - MINISTROKE

What is TIA ?

A transient ischaemic attack (TIA) is a type of stroke where symptoms last less than 24 hours. It is due to a temporary deficiency of blood supply to part of the brain. It starts suddenly, and may cause weakness or numbness in any part of the body. Symptoms may involve the face, arm and leg on one side or just one part of the body. Vision may be affected, often in just one eye. The attack usually lasts between 1 and 6 hours.

How does TIA occur ?

Most TIA’s are caused by clots blocking small arteries which supply blood to the brain. These clots often do not form in the small artery itself, but are carried there by blood flowing from a diseased artery closer to the heart. They can even come from the heart itself. They may consist of a clump of red blood cells or other cells called platelets. These block an artery but then break up so that blood flow to the brain is soon restored. They are more likely to occur with an irregular heartbeat such as atrial fibrillation, which favours clot formation in one of the chambers of the heart. Some patients have TIAs as a result of spasm in an artery or a sudden fall in blood pressure.

Why does TIA occur ?

Blood vessels are damaged and become diseased as part of a process called atheroma. A combination of factors such as high blood pressure, too much dietary fat, a raised blood cholesterol and smoking contribute to atheroma. People with atheroma in their blood vessels often have heart disease as well. Diabetes is known to increase the risk of premature atheroma.

Treatment involved for TIA

Blood tests, a chest x-ray and a heart tracing (ECG) are usually done. A special ultrasound test of the heart (echocardiogram) is done to check whether blood clot is present within the heart. A similar test on the blood vessels in the neck (carotid Dopplers) is performed, and enables the doctor to see if there is any narrowing or roughening of the arteries, which might be acting as a source of blood clots. A CT (x-ray) or MRI (magnetic) brain scan may be done to detect areas where blood clots have caused damage. Treatment often consists of taking regular low dose aspirin (or alternative drugs) which reduce the stickiness of blood cells and have been shown to reduce the rate of repeat TIA’s by up to 25%. Other blood thinning treatment (anticoagulants) are often used in patients who are forming blood clots in the heart. If the arteries in the neck are very narrow as a result of atheroma, an operation is sometimes carried out to clean them out (endarterectomy). People with high cholesterol may be put on a diet or on a drug to lower cholesterol to more normal levels. However, there is as yet no proof that this will lessen TIA attacks. However, the risk of subsequent heart attacks may be reduced by this approach.

During treatment for TIA

Aspirin may sometimes cause indigestion. If further TIA’s or side-effects occur while taking aspirin other drugs with similar benefits may be needed. Patients on anticoagulants need regular blood tests: overdose can cause bleeding or bruising.

After Treatment

TIA’s may settle down but the risk of a more substantial stroke is high, particularly in the first few months after a TIA. Attention to the risk factors mentioned earlier and to life style is important to reduce the risk. You may be advised not to drive for a while.

If TIA is left untreated

TIAs may settle without any treatment However, in the absence of treatment, the likelihood of a major stroke is that much higher.

Effects on family of TIA

TIAs are not inherited. Family and friends should encourage a healthy life-style.