How to recognize a ministroke or stroke — and what to do

If you suddenly experience a strange but fleeting symptom — your arm or face suddenly feels weak or numb — you might be tempted to brush it off, especially if it’s short-lived.

But if those odd, unexplained symptoms last more than a few seconds, they could signal a transient ischemic attack, or TIA. Commonly referred to as a ministroke, a TIA is caused by a temporary lack of blood in part of the brain. Most of the time a blood clot is to blame, and the symptoms resolve quickly because your body’s natural clot-dissolving action restores blood flow. But according to the American Stroke Association (ASA), these events should be called warning strokes rather than ministrokes.

“A TIA can be a harbinger of a much more serious stroke,” says Dr. Christopher Anderson, director of acute stroke services at Harvard-affiliated Massachusetts General Hospital. If a blood clot blocking a brain artery doesn’t dissolve and remains in place for more than a few minutes, it can destroy brain cells by depriving them of oxygen and nutrients. Known as an ischemic stroke, these account for 87% of all strokes. As many as 17% of people who have a TIA will suffer a full-blown ischemic stroke within the next 90 days, with the greatest risk in the first week.

What should you understand about TIAs?

A recent study found that women with short-lived sensory or visual symptoms were less likely to be diagnosed with TIA compared with men. One reason could be that migraines are more common in women. As a result, both women and doctors may be less likely to suspect a TIA in women with sensory or vision changes, which may occur with or without a migraine headache. “But it’s important to consider a TIA in all people with those symptoms, regardless of their gender,” says Dr. Anderson.

Other short-lived TIA symptoms may be easy to dismiss, says Dr. Anderson. “Sometimes, people will say, ‘That’s funny, I can’t feel one side of my face,’ and garble their words for a short time,” he says. People may repeatedly drop objects (a cooking utensil, for example) but then be able to function normally after a few minutes. Another classic TIA symptom is seeing what’s often described as a dark curtain dropping over one eye from top to bottom. This symptom is called amaurosis fugax (from the Greek amaurosis, meaning dark, and the Latin fugax, meaning fleeting).

BE-FAST when recognizing a stroke or TIA

The ASA coined the mnemonic FAST to help people recognize stroke symptoms. The first three letters, which stand for Face drooping, Arm weakness, and Speech difficulties) account for about 75% of the symptoms people experience during a stroke. (The T stands for Time to call 911.)

But some neurologists suggest adding two additional letters: B for balance and E for eyes. Balance is a tricky one, because balance problems can occur due to a range of problems other than a stroke, especially in older people, says Dr. Anderson. With a stroke, balance problems rarely appear in isolation; they usually occur in tandem with other symptoms such as leg weakness or vision problems, he explains. Vision problems during a TIA or stroke can include reduced, blurry, or double vision.

The simpler FAST makes sense for a public health campaign. But if you’re at risk, knowing BE-FAST may be the most helpful, as it may help you recognize even more potential TIAs and strokes. High blood pressure is the leading cause of stroke. Other risk factors to be aware of include smoking, diabetes, physical activity, and obesity. People with heart disease (such as coronary artery disease, atrial fibrillation, and heart failure) face a higher-than-normal risk of stroke. Talk to your doctor about your risks for stroke or TIA, and healthy steps you can take to lessen your chance of having either one.