Transient Ischemic Attack (TIA)
A transient ischemic attack (TIA) is a brief episode during which parts of the brain do not receive enough blood. Because the blood supply is restored quickly, brain tissue does not die as it does in a stroke. These attacks are often early warning signs of a stroke, however.
Stroke is the fifth-leading cause of death in the United States and the leading cause of adult disability.
A TIA starts suddenly, like ischemic strokes. The difference is that TIAs last only 2 to 30 minutes.
Symptoms may include:
- Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
- Sudden confusion
- Sudden trouble speaking
- Sudden trouble seeing in one or both eyes
- Sudden trouble walking
- Sudden dizziness, loss of balance or coordination
- Sudden, severe headache with no known cause
TIAs are sometimes called “warning strokes” and tend to happen multiple times. In many cases, TIAs are followed by strokes, usually within a year of the first attack.
Causes and Risk Factors
TIAs may be caused by a variety of factors, including:
- Narrowing of the arteries, usually caused by atherosclerosis. This is when fatty material builds up and hardens on an artery wall. This material can break off and get lodged in smaller blood vessels in the brain.
- Cerebral artery stenosis
- Spasms in the walls of the arteries
- High blood pressure
- A lack of oxygen in the blood flowing to the brain, which can occur when a person is severely anemic, has carbon monoxide poisoning or has leukemia or polycythemia, a condition that produces abnormal blood cells and clotting
Many disorders such as seizures, tumors, migraines or abnormal blood sugar levels, may provoke symptoms similar to those of TIA. While the suddenness of symptoms suggest clues about which area of the brain is affected, careful evaluation is necessary.
Imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MRI), are useful in diagnosing stroke and seeing which parts of the brain are damage. However, they are not useful for diagnosing TIA, because TIAs do not typically cause permanent damage that can be seen once the attack is over.
Several techniques can be used to confirm TIA if the blockage occurs in one or both carotid arteries. Diagnostic techniques include:
Carotid duplex imaging to assess the health of the main arteries carrying blood from the heart to the brain
Treatment of TIAs is aimed at preventing stroke. The major risk factors for stroke are:
Eliminating or reducing these risk factors is the first step in preventing strokes.
Other approaches to treating or preventing TIA may be used depending on the cause of the attack. If the cause is carotid artery stenosis, treatment may include a procedure to open the artery known as carotid artery stenting or another procedure known as carotid endarterectomy
If the attack was caused by a blood clot, medications can help break up the blood clot and prevent future clots. This may be as simple as an aspirin a day, or it may mean taking anticoagulants, such as heparin or warfarin.
A neurosurgical procedure known as endarterectomy may be considered if more than 70 percent of the blood vessel is blocked and the patient has had stroke-like symptoms in the past six months.
The goals of treatment are to prevent life-threatening complications that may occur soon after stroke symptoms develop, prevent future strokes, reduce disability, prevent long-term complications and help the patient get back as much normal functioning as possible through rehabilitation.