Transient Ischemic Attack

(TIA) Information

from Harvard Health Publishing, Harvard Medical SChool

How to recognize and respond to a "warning" stroke

Many people who suffer a first-time stroke had a prior warning from a transient ischemic attack (TIA), also known as a ministroke.

"TIAs usually produce typical stroke symptoms, but because they are mild and brief they tend to be missed or ignored," says Dr. Erica Camargo Faye, a stroke neurologist at Harvard-affiliated Massachusetts General Hospital. "But a TIA is your body warning that you're at high risk for a full stroke, and you need to listen."

How to recognize and respond to a "warning" stroke

graphic showing how to recognize the signs of a stroke, using the acronym BE FAST as described in the article
Many people who suffer a first-time stroke had a prior warning from a transient ischemic attack (TIA), also known as a ministroke.

"TIAs usually produce typical stroke symptoms, but because they are mild and brief they tend to be missed or ignored," says Dr. Erica Camargo Faye, a stroke neurologist at Harvard-affiliated Massachusetts General Hospital. "But a TIA is your body warning that you're at high risk for a full stroke, and you need to listen."

Why TIAs happen

A TIA occurs when too little oxygen-rich blood reaches part of the brain. Often, the underlying cause is fatty plaque buildup inside an artery in the neck, such as the carotid artery, or an artery in the brain. The plaque narrows the artery and invites blood clots to form on top of the plaque, impeding healthy blood flow.

Another cause is when a blood clot in the heart or carotid artery breaks away and travels to the brain, temporarily blocking a blood vessel there. Similarly, a sudden drop in blood pressure can decrease blood flow through a narrowed artery and trigger a TIA.

TIAs can last anywhere from 30 seconds to 20 minutes, although most usually last at least five minutes. "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. A TIA does not guarantee you will have a future stroke, but it does suggest you are at high risk.

Nearly one in five people who have a suspected TIA will experience a full-blown stroke within three months, according to a scientific statement from the American Heart Association in the March 2023 issue of the journal Stroke. The risk of a stroke is highest during the 48 hours following the initial TIA.

Early recognition of the likely cause of a TIA is the best way to prevent a stroke. Because most TIAs are related to a temporary clot forming in a narrowed brain artery, the usual treatment begins with two antiplatelet drugs, such as aspirin and clopidogrel (Plavix), or an anticoagulant medication to prevent additional blood clots from forming.

Less often, a major blockage in one of the two carotid arteries is the culprit and needs to be opened by surgery or a procedure called endarterectomy.

Know the warning signs

TIAs can recur with the same symptoms or different ones. The acronym BE-FAST can help people recognize signs and symptoms. Most people experience one or more of these during a TIA:

B: Balance. Balance problems caused by a TIA often make it difficult to stand up, or you may fall to one side.

E: Eyes. The most common vision problem is being unable to see from one or both eyes. Often, people see a dark gray shade that blocks half or all of their vision. Blurred or double vision can also occur.

F: Face. The face may droop on one or both sides. Usually, the corner of the mouth appears pulled down, and the person can't smile normally.

A: Arm weakness. This is the most common symptom and usually occurs on only one side and may also include numbness or tingling.

S: Speech difficulty. Slurred or garbled speech is the most common type of speech problem, but some people struggle to find words or understand what others say. This deficit also extends to writing and texting.

T: Time. This is not a symptom, but a command: it's time to call 911 or go straight to an emergency room, even if the symptoms lasted only one or two minutes.