A transient ischemic attack (TIA) is like a stroke, producing similar symptoms, but usually lasting only a few minutes and causing no permanent damage.
Often called a ministroke, a transient ischemic attack may be a warning. About 1 in 3 people who have a transient ischemic attack will eventually have a stroke, with about half occurring within a year after the transient ischemic attack.
A transient ischemic attack can serve as both a warning and an opportunity — a warning of an impending stroke and an opportunity to take steps to prevent it.
Transient ischemic attacks usually last a few minutes. Most signs and symptoms disappear within an hour. The signs and symptoms of a TIA resemble those found early in a stroke and may include sudden onset of:
- Weakness, numbness or paralysis in your face, arm or leg, typically on one side of your body
- Slurred or garbled speech or difficulty understanding others
- Blindness in one or both eyes or double vision
- Dizziness or loss of balance or coordination
- Sudden, severe headache with no known cause
You may have more than one TIA, and the recurrent signs and symptoms may be similar or different depending on which area of the brain is involved.
When to see a doctor
Since TIAs most often occur hours or days before a stroke, seeking medical attention immediately following a possible TIA is essential. Seek immediate medical attention if you suspect you've had a transient ischemic attack. Prompt evaluation and identification of potentially treatable conditions may help you prevent a stroke.
A transient ischemic attack has the same origins as that of an ischemic stroke, the most common type of stroke. In an ischemic stroke, a clot blocks the blood supply to part of your brain. In a transient ischemic attack, unlike a stroke, the blockage is brief, and there is usually no permanent damage.
The underlying cause of a TIA often 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 the development of a clot. A blood clot moving to an artery that supplies your brain from another part of your body, most commonly from your heart, also may cause a TIA.
Some risk factors for a transient ischemic attack and stroke can't be changed. Others you can control.
Risk factors you can't change
You can't change the following risk factors for a transient ischemic attack and stroke. But knowing you're at risk can motivate you to change your lifestyle to reduce other risks.
- Family history. Your risk may be greater if one of your family members has had a TIA or a stroke.
- Age. Your risk increases as you get older, especially after age 55.
- Sex. Men have a slightly higher likelihood of a TIA and a stroke, but more than half of deaths from strokes occur in women.
- Prior transient ischemic attack. If you've had one or more TIAs, you're 10 times more likely to have a stroke.
- Sickle cell disease. Also called sickle cell anemia, a stroke is a frequent complication of this inherited disorder. Sickle-shaped blood cells carry less oxygen and also tend to get stuck in artery walls, hampering blood flow to the brain. However, with proper treatment for sickle cell disease, you can lower your risk of a stroke.
- Race. Black people are at greater risk of dying of a stroke, partly because of the higher prevalence of high blood pressure and diabetes among blacks.
Risk factors you can take steps to control
You can control or treat a number of factors — including certain health conditions and lifestyle choices — that increase your risk of a stroke. Having one or more of these risk factors doesn't mean you'll have a stroke, but your risk particularly increases if you have two or more of them.
- High blood pressure. The risk of a stroke begins to increase at blood pressure readings higher than 140/90 millimeters of mercury (mm Hg). Your doctor will help you decide on a target blood pressure based on your age, whether you have diabetes and other factors.
- High cholesterol. Eating less cholesterol and fat, especially saturated fat and trans fat, may reduce the plaques in your arteries. If you can't control your cholesterol through dietary changes alone, your doctor may prescribe a statin or another type of cholesterol-lowering medication.
- Cardiovascular disease. This includes heart failure, a heart defect, a heart infection or an abnormal heart rhythm.
- Carotid artery disease. The blood vessels in your neck that lead to your brain become clogged.
- Peripheral artery disease (PAD). The blood vessels that carry blood to your arms and legs become clogged.
- Diabetes. Diabetes increases the severity of atherosclerosis — narrowing of the arteries due to accumulation of fatty deposits — and the speed with which it develops.
- High levels of homocysteine. Elevated levels of this amino acid in your blood can cause your arteries to thicken and scar, which makes them more susceptible to clots.
- Excess weight. A body mass index of 25 or higher and a waist circumference greater than 35 inches (89 centimeters) in women or 40 inches (102 centimeters) in men increase risk.
- Cigarette smoking. Smoking increases your risk of blood clots, raises your blood pressure and contributes to the development of cholesterol-containing fatty deposits in your arteries (atherosclerosis).
- Physical inactivity. Engaging in 30 minutes of moderate-intensity exercise most days helps reduce risk.
- Poor nutrition. Eating too much fat and salt, in particular, increases your risk of a TIA and a stroke.
- Heavy drinking. If you drink alcohol, limit yourself to no more than two drinks daily if you're a man and one drink daily if you're a woman.
- Use of illicit drugs. Avoid cocaine and other illicit drugs.
- Use of birth control pills. All oral contraceptives increase your risk of a stroke but taking certain ones may be more risky than others. If you're using birth control pills, talk to your doctor about how the hormones may affect your risk of a TIA and a stroke.
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.
- Limit cholesterol and fat. Cutting back on cholesterol and fat, especially saturated fat and trans fat, in your diet may reduce buildup of plaques in your arteries.
- Eat plenty of fruits and vegetables. These foods contain nutrients such as potassium, folate and antioxidants, which 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 excess sodium may increase blood pressure in people who are sensitive to sodium.
- Exercise regularly. If you have high blood pressure, regular exercise is one of the few ways you can lower your blood pressure without drugs.
- Limit alcohol intake. Drink alcohol in moderation, if at all. The recommended limit is no more than one drink daily for women and two a day for men.
- Maintain a healthy weight. Being overweight contributes to other risk factors, such as high blood pressure, cardiovascular disease and diabetes. Losing weight with diet and exercise may lower your blood pressure and improve your cholesterol levels.
- Don't use illicit drugs. Drugs such as cocaine are associated with an increased risk of a TIA or a stroke.
- Control diabetes. You can manage diabetes and high blood pressure with diet, exercise, weight control and, when necessary, medication.