Transient Ischemic Attack (TIA)
A transient ischemic attack (TIA) is a transient stroke that lasts only a few minutes. It occurs when the blood supply to part of the brain is briefly interrupted. TIA symptoms, which usually occur suddenly, are similar to those of stroke but do not last as long. Most symptoms of a TIA disappear within minutes to an hour, although they may persist for up to 24 hours.
- Numbness or Weakness in the face, arm, or leg, especially on one side of the body;
- Confusion or difficulty in talking or understanding speech;
- Trouble seeing in one or both eyes; and
- Difficulty with walking, dizziness, or loss of balance and coordination.
Even though a TIA doesn’t last very long and leaves no permanent effects, it’s far from an insignificant event. A TIA can serve as both a warning and an opportunity — a warning of an impending stroke and an opportunity to take steps to prevent it.
TIAs are often warning signs that a person is at risk for a more serious and debilitating stroke. About one-third of those who have a TIA will have an acute stroke some time in the future. Many strokes can be prevented by heeding the warning signs of TIAs and treating underlying risk factors.
Factors Linked to TIA
The most important treatable factors linked to TIAs and stroke are:
- High blood pressure,
- Cigarette smoking,
- Heart disease,
- Carotid artery disease,
- Heavy use of alcohol.
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.
Because there is no way to tell whether symptoms are from a TIA or an acute stroke, patients should assume that all stroke-like symptoms signal an emergency and should not wait to see if they go away. A prompt evaluation (within an hour) is necessary to identify the cause of the TIA and determine appropriate therapy. Depending on the 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 TIA.
The use of antiplatelet agents, particularly aspirin, is a standard treatment for patients at risk for stroke. People with atrial fibrillation (irregular beating of the heart) may be prescribed anticoagulants.
A physical examination may reveal evidence that suggests presence of arterial plaques. Doctor may hear a sound (bruit) over the carotid artery in the patients neck during an examination with a stethoscope. He may observe cholesterol fragments (emboli) in the tiny blood vessels of the patient’s retina during an eye examination with an ophthalmoscope.
These tests also may help diagnose TIA:
1) Carotid ultrasonography. A transducer sends high-frequency sound waves into the neck. After the sound waves pass through tissue and back, doctor can analyze images on a screen to look for narrowing or clotting in the carotid arteries.
2) Computed tomography (CT) scanning. CT scanning of the head uses X-ray beams to assemble a composite, three-dimensional look at the brain.
3) Magnetic resonance imaging (MRI). This procedure, using a strong magnetic field, can generate a composite, three-dimensional view of the brain.
4) Magnetic resonance angiography (MRA). This procedure is a noninvasive method of evaluating the arteries in the neck and brain. It uses a strong magnetic field, similar to MRI.
5) Transesophageal echocardiogram (TEE). During this procedure, a flexible probe with a transducer built into it is placed in your esophagus — the tube that connects the back of your mouth to your stomach. Because the esophagus is directly behind the heart, very clear, detailed ultrasound images can be created, allowing doctors to get a better view of some things such as blood clots that they might not see clearly in a traditional echocardiography exam.
6) Arteriography. This procedure gives a view of arteries in the brain not normally seen in X-ray imaging. A radiologist inserts a thin, flexible tube (catheter) through a small incision, usually in the groin. The catheter is manipulated through the major arteries and into the carotid or vertebral artery. Then, the radiologist injects a dye through the catheter to provide X-ray images of the arteries in the brain.
Several medications may be used to decrease the likelihood of a stroke following a TIA. The medication selected depends on the location, cause, severity and type of TIA. Two frequently prescribed types of drugs are:
These medications make the platelets, one of the circulating blood cell types, less likely to stick together. Clot formation is started by sticky platelets when there’s an injury to blood vessels. The process is then completed by clotting proteins in blood plasma. The most frequently used antiplatelet medication is aspirin. Aspirin is also the least expensive treatment with the fewest potential side effects. Studies have shown that aspirin may reduce the risk of stroke by about 30 percent if you’ve had a TIA.
Your doctor may also consider prescribing Aggrenox, a combination of low-dose aspirin and the antiplatelet drug dipyridamole, to reduce blood clotting. Dipyridamole works in a slightly different way than aspirin. If aspirin doesn’t stop you from having further TIAs or if you can’t take aspirin, your doctor may instead prescribe the antiplatelet drug clopidogrel (Plavix) or ticlopidine (Ticlid). Both require monitoring by your doctor.
These drugs include heparin and warfarin (Coumadin). They affect clotting system proteins instead of platelet function. Heparin is used short term and warfarin over a longer term. These drugs have a profound anticoagulation effect and therefore require careful monitoring.
If you have a moderately or severely narrowed — 60 percent or more — neck (carotid) artery, your doctor may suggest carotid endarterectomy . This preventive surgery clears carotid arteries of atherosclerotic plaques before another TIA or stroke can occur. An incision is made to open the artery, the plaques are removed, and the artery is closed.
In selective cases, a procedure called carotid angioplasty may be used instead. This procedure involves using a balloon-like device to open a clogged artery and placement of a small wire tube (stent) into the artery to keep it open.