Mini-Strokes: Major Risks
Tuesday, August 30, 2005
Coretta Scott King, 78, is in an Atlanta hospital, facing speech, occupational and physical therapy after a stroke and minor heart attack on Aug. 16. Those events were preceded by two transient ischemic attacks (TIAs), or mini-strokes, during which she had trouble speaking, according to published reports.
Senate Democratic leader Harry Reid, 65, of Nevada had a mini-stroke the same week but has suffered no complications, according to wire service reports.
These two cases have raised the profile of TIAs and sparked questions, including how any stroke can be properly described as "mini."
Mini-strokes are "essentially the same thing as a stroke, except that it gets better [and the] symptoms go away," said Chelsea Kidwell, medical director of the Stroke Center at Washington Hospital Center.
King's experience is not unique -- those who have had mini-strokes are at increased risk for a major stroke. Patients should view TIAs as "an opportunity to prevent a subsequent stroke," Kidwell said. "The only difference [between someone who has had a TIA and someone who has had a stroke] is the person with the TIA got very lucky [but] next time they may not get so lucky," she said. Strokes are the third leading cause of death in the U.S., according to the Centers for Disease Control and Prevention.
Some symptoms of TIA are subtle but ignoring them can be deadly, so those known to be at higher risk for stroke should be aware of the signs and contact a doctor immediately if they experience them. Symptoms depend on "which blood vessel is involved . . . [but] for the most part consciousness is not affected," said Larry B. Goldstein, director of the stroke center at Duke University School of Medicine and chair of the stroke council for the American Stroke Association (ASA).
"Because there is no way to tell [in the short term] whether symptoms are from a TIA or an acute stroke, patients should assume that all stroke-like symptoms signal an emergency and should not wait to see if they go away," according to the National Institute of Neurological Disorders and Stroke (NINDS).
More questions and answers:
How would I know if I'm having a mini-stroke?
It may start suddenly and last only a few minutes. You may be confused or have sudden difficulty seeing, walking, talking or understanding conversation. According to the Mayo Clinic, common signs include: slurred or garbled speech or trouble understanding others; double vision or sudden blindness in one or both eyes; dizziness, loss of coordination or balance; numbness, weakness or paralysis in the face, leg or arm -- often on one side of the body.
But the symptoms disappear, usually quickly-- at most, in 24 hours. You may not even realize what's happening.
In fact, the mildness of the symptoms can make TIAs difficult for a person to recognize. In an ASA-sponsored study of more than 10,000 people published in 2003, about 200 said they had been told by a doctor that they'd had a TIA. Of those, only 64 percent had seen a doctor within 24 hours of the mini-stroke. Another 300 "recalled symptoms consistent with TIA but did not seek medical attention."
How often do TIAs lead to strokes?
About a third of those who have had a TIA will go on to have a stroke, according to MedlinePlus, a service run by the National Library of Medicine and the National Institutes of Health. And about a third of people who have a TIA will have another mini-stroke. "It's generally understood that the more [TIA] events you have, the greater your risk" of stroke, Kidwell said.
Do some people with TIAs know they're having a stroke?
Yes, but they don't always dial 911. In some cases, the part of the brain used to make quick-reaction decisions may be affected, said Goldstein. If you're at risk, it's important that your loved ones know what to do, too. Talk with them about the symptoms today, Goldstein and Kidwell suggest.
Is there really a difference between a "mini" and a "major" stroke?
Yes. The effects of a TIA are temporary, while the effects of a major stroke can be permanent. Any type of stroke is caused by interruption of blood supply to parts of the brain, which causes decreased brain function. If symptoms resolve themselves within 24 hours, the episode is deemed a TIA; if they continue beyond that, it is called a stroke.
A variety of factors can cause loss of blood flow to the brain, including blood clotting in an artery; narrowing, injury or inflammation of a blood vessel; cancer, a blood disorder (such as sickle cell anemia), or other condition; and a blood clot moving to the brain from another place in the body.
TIAs are "ischemic" strokes -- where the blood vessel clogs from within. This type accounts for about 83 percent of all strokes, according to the ASA.
A second type -- which is not involved in TIAs -- are "hemorrhagic" strokes, where a weakened blood vessel ruptures, causing blood to accumulate in the brain and compress brain tissue. These account for about 17 percent of all strokes.
How do I know if I'm at risk for a TIA or stroke?
Risks for having TIAs are similar to those for heart disease. They include "things you can do things about" and "things you can't do anything about," said Goldstein.
Factors you can't control include family history, age, sex and race. You're at greater risk if a family member has had a TIA or stroke. Men have strokes more often than women. African Americans face greater risks of death from stroke than other groups, according to the Mayo Clinic's Web site.
As for those things you can control, they include high blood pressure, diabetes and cholesterol. Proper weight, diet and exercise decreases your risk for stroke, according to the ASA. Heart disease and cigarette smoking put you at higher risk for stroke, too.
Does my risk of TIA or stroke increase as I get older?
Yes. After age 55, the risk doubles every decade through at least the eighties, Goldstein said. Two-thirds of strokes and TIAs happen in those 65 and older.
Is there any way to predict risk of a major stroke after a TIA?
A group of British researchers found that likelihood of stroke within seven days of a TIA is "highly predictable," based on blood pressure readings, clinical features and duration of symptoms, according to a study in The Lancet in July.
In a 2000 study of more than 1,700 TIA patients, published in the Journal of the American Medical Association, 91 people had a stroke within two days of their mini-strokes. Another 89 patients had strokes within 90 days.
Are there treatments for TIA or stroke?
Examination within 60 minutes of the start of symptoms provides the best opportunity for successful treatment, according to NINDS. Your doctor may prescribe or administer medication to dissolve blood clots and reduce the chances of future blockages, but some drugs are only effective within three hours of symptom onset. Your doctor might also recommend surgery or an angioplasty to unblock arteries.
National Institute of Neurological Disorders and Stroke, http:/
American Stroke Association, http:/
Mayo Clinic, http:/