| Signs and symptoms |
Transient ischemic attacks usually last from 2 to 30 minutes, and all effects disappear within 24 hours. TIA signs and symptoms resemble those found early in a stroke and may include:
- Sudden weakness, an abnormal feeling, or paralysis in your face, arm or leg, typically on one side
of your body
- Slurred or garbled speech or difficulty understanding others
- Sudden blindness in part of your visual field, sometimes as if a gray or black curtain is falling
over or crossing your visual field
- Dizziness, loss of balance or loss of coordination
| Causes |
The cause of a TIA is a temporary decrease in blood supply to part of your brain. The attack can last from just a few minutes to a half-hour.
A TIA has the same origins as that of an ischemic stroke. In this most common type of stroke, a clot blocks the blood supply to part of your brain. But in contrast to a stroke, which involves a more prolonged lack of blood supply and may result in permanent damage, a TIA leaves no lasting effects.
The underlying cause of a TIA usually is a buildup of cholesterol-containing fatty deposits called plaques (atherosclerosis) in an artery or one of its branches that supplies oxygen and nutrients to your brain. Plaques can decrease the blood flow through an artery or lead to development of a clot.
| Risk factors |
You can't change the following risk factors for TIA and stroke. But knowing you're at risk can motivate you to change your lifestyle to reduce other risks.
- Family history. Your risk is greater if one of your parents or siblings has had a TIA or a
stroke.
- Age. Generally, your risk increases as you get older, especially if you're older than age 65.
- Sex. If you're a man, your risk is higher than a woman's until age 55. After age 55, when
estrogen levels fall, a woman's risk equals a man's.
- Race. Blacks are at greater risk than other ethnic groups. The reason is partly because of their higher prevalence of high blood pressure and diabetes.
- High blood pressure. Having high blood pressure increases your risk of TIA or stroke. Poor
diet, lack of exercise and being overweight contribute to this risk factor.
- Cardiovascular disease. Conditions including congestive heart failure, a previous heart
attack, acute heart valve disease or valve replacement, and atrial fibrillation — an irregular and,
often, rapid heartbeat — increase your risk. Your heart doesn't pump blood efficiently or it beats
irregularly. This can lead to blood clots.
- Cigarette smoking. Smoking contributes to development of cholesterol-containing fatty
deposits in your arteries. Nicotine increases your heart rate and blood pressure. The carbon monoxide in
cigarette smoke replaces oxygen in your blood, decreasing the amount of oxygen delivered to your
tissues, including your brain.
- Diabetes. Diabetes increases the severity of atherosclerosis — narrowing of the arteries due
to accumulation of fatty deposits — and the speed with which it develops, and interferes with normal
breakdown of fibrin, a protein in your blood that holds clots together.
- Undesirable levels of blood cholesterol. High blood levels of low-density lipoprotein (LDL)
cholesterol and low levels of high-density lipoprotein (HDL) cholesterol increase your risk of narrowed
or blocked arteries. If there is evidence of narrowing in the artery supplying blood to the front part
of your brain (carotid), your doctor may recommend studies evaluating your arteries, even if you haven't
had symptoms.
- Elevated homocysteine level. This amino acid — a building block of protein — naturally occurs in your blood. Elevated levels of homocysteine can cause arteries to thicken and scar, making it more likely that cholesterol will clog arteries. Taking a combination of B complex vitamins — B-6, B-12 and folic acid — has been shown to reduce blood levels of homocysteine.
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| When to seek medical advice |
If you suspect you may have had symptoms of a transient ischemic attack but the symptoms have passed, see your doctor. You'll need an immediate medical evaluation to determine what caused the problem. It's important to identify the cause so that you can take steps to prevent a stroke.
| Screening and diagnosis |
A TIA is characterized by its rapid onset, short duration and your body's return to its normal state. Your doctor may diagnose a TIA based just on the medical history of the event rather than on anything found during a physical and neurologic examination.
In some people who've experienced a TIA, a physical examination may reveal evidence that suggests presence of arterial plaques. Your doctor may hear a sound (bruit) over the carotid artery in your neck during an examination with a stethoscope. Or your doctor may observe cholesterol fragments (emboli) in the tiny blood vessels of your retina, at the back of your eye, during an eye examination with an ophthalmoscope.
These tests also may help diagnose TIA:
- Carotid ultrasonography. A wandlike device (transducer) sends high-frequency sound waves into
your neck. After the sound waves pass through tissue and back, your doctor can analyze images on a
screen to look for narrowing or clotting in the carotid arteries.
- Computed tomography (CT) scanning. CT scanning of the head uses X-ray beams to assemble a
composite, three-dimensional look at your brain.
- Magnetic resonance imaging (MRI).This procedure, using a strong magnetic field, can generate
a composite, three-dimensional view of your brain.
- 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.
- 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 your 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.
- Arteriography. This procedure gives a view of arteries in your brain not normally seen in X-ray imaging. A radiologist inserts a thin, flexible tube (catheter) through a small incision, usually in your groin. The catheter is manipulated through your major arteries and into your carotid or vertebral artery. Then, the radiologist injects a dye through the catheter to provide X-ray images of the arteries in your brain.
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| Treatment |
Once your doctor has determined the cause of a TIA, the goal of treatment is to correct the abnormality and prevent a stroke. Depending on the cause of the TIA, your doctor may prescribe medication to reduce the tendency for blood to clot, and may recommend surgery.
Medications
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:
- Antiplatelet drugs. These medications make your 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.
- Anticoagulants. 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 (end-ahr-tur-EK-tuh-me). 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 balloonlike device to open a clogged artery and placement of a small wire tube (stent) into the artery to keep it open.
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| Prevention |
Knowing your risk factors and living healthfully are the best things you can do to prevent a TIA. Included in a healthy lifestyle are regular medical checkups. Also:
- Don't smoke. Stopping smoking reduces your risk of a TIA or a stroke. Ten years after
quitting, your risk is the same as that of a nonsmoker.
- Limit cholesterol and fat. Cutting back on cholesterol and fat, especially saturated fat, in
your diet may reduce buildup of plaques in your arteries.
- Eat plenty of fruits and vegetables. These foods contain such nutrients as potassium, folic
acid and antioxidants that may protect against a TIA or a stroke.
- Limit sodium. If you have high blood pressure, avoiding salty foods and not adding salt to
food may reduce your blood pressure. Avoiding salt may not prevent hypertension. But in about 10 percent
of healthy Americans who are sensitive to sodium, excess sodium may increase blood pressure.
- Exercise regularly. If you have high blood pressure, regular exercise is one of the few ways
you can lower your pressure without drugs.
- Avoid alcohol. Drink alcohol in moderation, if at all.
- Maintain a healthy weight. Being overweight contributes to other risk factors, such as high
blood pressure, cardiovascular disease and diabetes. Losing as little as 10 pounds with diet and
exercise may lower your blood pressure and improve your cholesterol levels.
- Don't use illicit drugs. Many drugs such as cocaine are associated with a significant risk of a TIA or a stroke.
- Control diabetes. You can manage both diabetes and high blood presure with diet, exercise, weight control and, when necessary, medication.
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— June 26, 2001 —