Transient Ischemic Attack
Pronounced: trans-EE-ent isk-EE-mik uh-takEn Español (Spanish Version)
Transient ischemic attack (TIA) refers to temporary brain dysfunction lasting no longer than 24 hours due to a shortage of blood and oxygen. It sometimes is referred to as a "mini-stroke." TIA is a serious condition that serves as a warning for a stroke . About 30% of stroke patients have had a TIA at some point in the past.
Blood Supply to the Brain
© 2008 Nucleus Medical Art, Inc.
A TIA results from a temporary blockage of the blood supply to the brain. A build-up of plaque in the arteries leading to the brain (most importantly the carotid artery in the front of the neck) and hardening of the arteries usually are present.
Reasons for the blockage may include:
- A blood clot or a piece of plaque (called an embolus) from inside the wall of an artery breaks off and blocks blood flow to a portion of the brain.
- A blood clot dislodges from the heart and moves to the brain.
- Temporary low blood pressure in the brain may occur due to narrowed arteries in the neck.
Blood and blood-clotting disorders such as:
- Anemia (too few red blood cells)
- Polycythemia (too many red blood cells)
- Hyperviscosity (abnormal thickening of the blood)
- Vasculitis or blood vessel inflammation
- Endocarditis (infection of the lining of the heart)
A risk factor is something that increases your chance of getting a disease or condition.
Risk factors for TIA and stroke are similar:
- Family history of stroke
- Age: 45 or older (highest risk 60-80 years of age); more common in men than women in younger age groups
- Atrial fibrillation , a common irregular heart rhythm.
- High blood pressure
- Excessive alcohol use
- High cholesterol
- Certain medical conditions:
TIA symptoms occur abruptly and usually last less than 10 minutes, but they may persist for up to 24 hours. The effects differ depending on the location of the blockage. TIA symptoms are similar to those of a stroke and warrant immediate medical attention.
Symptoms may include:
- Blindness in one eye, often described as a window shade dropping, and/or other visual problems.
- Weakness, numbness, or tingling of the face, arm, leg, or one side of the body (usually affects one side of the body, but there are exceptions).
- Difficulty speaking or understanding words
- Dizziness, unsteadiness of gait, or falling
- Trouble with balance or coordination
- Loss of consciousness
- Sudden confusion or loss of memory
The doctor will ask about your symptoms and medial history, and perform a physical exam, paying particular attention to your blood pressure and nervous system. A primary goal will be to determine your stroke risk.
Tests may include:
- Blood tests—such as a complete blood count, blood sugar (glucose), cholesterol and other fat levels, clotting factors, and a check of other elements in the blood
- Electrocardiogram (EKG)—to measure heart rhythm (which would be irregular in, for example, atrial fibrillation) and check for other signs of heart disease
- Doppler ultrasound—a test that uses sound waves to help determine if there is compromised blood flow in the arteries supplying the brain
- Echocardiogram—another ultrasound test to look for blood clots and valve abnormalities within the heart
- CT scan of the head—a type of x-ray that uses a computer to create images of structures inside the head; in this case, to look for evidence of bleeding or other damage to the brain
- MRI scan of the head—a test that uses powerful magnetic radiowaves to create images of structures inside the head; in this case, to look for evidence of bleeding or other damage to the brain
- Magnetic resonance angiography (MRA)—generally performed prior to carotid artery surgery to determine how much the artery has narrowed. Gadolinium, a type of dye, may be injected into your vein for this test.
- Arteriogram—a test in which contrast dye is injected into selected arteries and x-ray images are produced to precisely locate the blockage and to determine its extent; like MRA, this test is usually done in preparation for surgery on the carotid arteries.
- Electroencephalogram (EEG)—a test that can detect the presence of seizures by measuring brain waves (used only if a seizure is suspected)
A TIA places you at greater risk for having a stroke, and the risk is actually highest in the first week after your TIA. Therefore, rapid treatment aims to decrease stroke risk through lifestyle changes, medication, and surgery. If the cause of the TIA is a treatable condition, such as atrial fibrillation, severe anemia, or vasculitis, it must be promptly treated.
Smokers must quit. Patient with diabetes, hypertension , and/or high cholesterol must make every effort to effectively address these conditions through regular exercise, appropriate dietary changes, and other lifestyle interventions.
In addition, doctors often prescribe blood sugar, blood pressure, and cholesterol-lowering medications to treat these risk factors. Most patients are also prescribed aspirin or other drugs to decrease the risk of clot formation, unless there is a reason not to prescribe them. There is still some uncertainty about whether the use of several drugs together offers benefit over aspirin alone.
If the carotid artery on the same side as the TIA is 70% blocked or more, doctors may recommend a carotid endarterectomy, or other less invasive procedures, to remove the plaque deposits. Since these procedures can sometimes cause strokes, it is not routinely performed if there are no symptoms and less than 70% blockage.
The following strategies may help reduce the chance of TIAs and stroke:
- Exercise regularly, with your doctor's approval.
- Eat a healthful diet, one that is low in saturated fat and rich in whole grains, fruits, and vegetables.
- Maintain a healthy weight.
- If you smoke, quit.
- Drink alcohol in moderation. Moderate alcohol intake is no more than two drinks per day for men and one drink per day for women.
- Control blood pressure, high cholesterol, and diabetes with medications as needed.
American Heart Association
National Stroke Association
Canadian Society for Vascular Surgery
Heart and Stroke Foundation of Canada
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Last reviewed December 2007 by J. Peter Oettgen, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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