An estimated 795,000 people get a first-time stroke every year, and there is a good chance they were warned. Transient ischemic attacks (TIAs), also known as ministrokes, share many of the typical stroke symptoms. Yet they often are mild and brief, which is why they routinely get missed or ignored.
"A TIA is your body sounding a loud alarm that you're at high risk for a full stroke, and you need to listen," says Dr. Erica Camargo Faye, a stroke neurologist at Harvard-affiliated Massachusetts General Hospital.
Different kinds of blockage
A TIA occurs when not enough oxygen-rich blood reaches part of the brain. Often, the underlying cause is fatty plaque buildup inside arteries in the neck, such as the carotid artery, or in the brain itself. The plaque narrows the arteries and also invites a blood clot (called a thrombus) to form on top of the plaque, making it hard for blood to flow past it.
Another cause is a blood clot in the heart or the carotid artery that breaks off, travels to the brain, and temporarily blocks a blood vessel there. Similarly, a drop in blood pressure can slow blood flow through a narrowed part of an artery.
The signs of TIA are the same as a regular stroke and include one or more of the following, according to the CDC:
- Numbness or weakness of the face, arm, or leg, especially on one side of the body.
- Confusion, problems speaking or understanding speech, slurred speech.
- Vision problems, including double vision, loss of vision in one eye, or loss of vision on one side of the visual field.
- Trouble walking, dizziness, loss of balance or coordination.
TIAs typically last anywhere from approximately 30 seconds to 10 to 20 minutes, although they can go on for up to an hour or longer. "TIAs also can happen when you are asleep, and you may never know it happened," says Dr. Camargo Faye.
TIAs often recur with no pattern. "The same symptoms can appear, or there can be new ones," she says. "Less commonly, attacks may become progressively worse."
These attacks can be tough to recognize because people often blame normal aging for symptoms such as taking a sudden stumble while walking, trouble getting out the right words, or feeling dizzy. "And because TIAs don't last long and don't always have an immediate lasting effect, it's easy for people to shrug them off," says Dr. Camargo Faye.
Know the risks
A TIA does not guarantee you will have a future stroke; it only tells you that you are at high risk. According to the American Heart Association, about 9% to 17% of people who experience a TIA have a stroke within 90 days.
"If you notice any symptoms, even if they only last for several seconds, you should react as if it's a major stroke and seek immediate medical care," says Dr. Camargo Faye.
This applies even if you have known conditions that can mimic a TIA, such as vertigo or dizziness from low blood pressure. "It's always best to err on the side of caution, and at least discuss the symptoms with your doctor," she adds.
Preventing a TIA
TIAs and regular strokes also share many risk factors, such as smoking, high blood pressure, alcohol misuse, diabetes, a high cholesterol level, and excessive weight gain.
Another condition linked to TIA is atrial fibrillation, a quivering or irregular heartbeat. The uncoordinated movement of the atria (the upper chambers of the heart) can lead to the formation of a blood clot that can then travel to the brain and cause a TIA.
Some research suggests that excessive amounts of testosterone replacement therapy could increase a man's risk of cardiovascular disease, raising his TIA and stroke risk.
"It is essential men get regular check-ups to identify these problems so they can make appropriate diet and lifestyle changes," says Dr. Camargo Faye.