Focus on Transient Ischemic Attack: A Sign that More Serious Stroke Risk is Increased
About 80 percent of all strokes are called “ischemic” strokes. “Ischemic” means a lack of oxygen and nutrients. The brain gets its oxygen and nutrients from blood, which travels through a network of arteries. When the passageways for blood are blocked or narrowed, blood supply is diminished, and ischemic stroke can be the result.
Blood clots that block the flow of blood are the cause of most ischemic strokes. Underlying causes can include
- Buildup of plaque, or fatty deposits, in the arteries
- Hypertension (high blood pressure)
- Atrial fibrillation (heart rhythm disorder)
- Cardiomyopathy (heart muscle disease)
- Mitral valve disease
- Inflammation of the blood vessels
- Blood abnormalities and diseases (such as sickle-cell disease)
Although ischemic strokes vary in terms of how long symptoms last and how severe they are, the initial symptoms are basically the same:
- Numbness or weakness in the face, arm or leg, especially on one side of the body
- Confusion or difficulty talking or understanding speech
- Trouble seeing in one or both eyes
- Dizziness, loss of balance or difficulty walking
Ischemic strokes can be categorized according to severity. There are what’s called reversible ischemic neurologic deficits, or RINDS, in which symptoms can last from 24 hours to three weeks. There are minor ischemic strokes, which have milder symptoms that usually don’t go away, and there are major ischemic strokes, with severe symptoms that last for life.
And then there are transient ischemic strokes, or TIAs. A TIA lasts less than 24 hours and the numbness, confusion or dizziness are reversible.
Transient ischemic stroke: “mini-strokes” of great importance
First of all, even though a TIA doesn’t have lasting effects, it is considered an emergency. Since the symptoms of stroke are the same, you don’t know what kind of stroke you’re having. Immediate treatment is essential, so calling 911 and getting to the hospital right away is a must.
The second most important thing to know about TIAs is that they are telltale signs that your risk of having a more serious stroke is greatly
- Between 30 and 40 percent of people who have had a TIA go on to have a more serious stroke later.
- The risk remains high within the first year after the TIA.
- The risk is highest in the first few months after the TIA, especially if you have other stroke risk factors.
If TIA is your diagnosis…
To determine whether you have had a TIA or other type of stroke, your doctor will conduct a physical exam. Part of this exam will have a neurological component. Your doctor will test your reflexes, speech and movement and perform other tests to figure out how seriously your brain has been affected. You may also have some imaging tests, such as CT or MRI scans to see what’s going on in your brain. Blood tests may also be a part of the exam.
If you’ve had a TIA, the cause of it will determine what the treatment should be. Blood thinning medications may be prescribed. Surgery could be necessary in some cases. Daily aspirin may be recommended. Statins may be prescribed to lower your cholesterol levels. If your blood pressure is high, you may get medication for that.
Your doctor will probably also discuss lifestyle changes you’ll need to make to lower your risk of more serious stroke in the future. Smoking, drinking that’s not in moderation, lack of exercise and an unhealthy diet are all factors that contribute to stroke risk. (A recent study in the Journal of the American Medical Association showed that eating fish once a month or more can reduce the risk of ischemic stroke in men. See this issue’s recipe for a heart-healthy fish recipe.)
Even though a TIA is a serious, emergency event, it does have a positive side. It puts you on warning that your risk of stroke is greatly increased. And while that’s probably not something you like hearing, you’re in a good position to make the changes you’ll need to make to lower your risk.
Don’t forget, strokes are the third leading cause of death in the U.S, according to the Centers for Disease Control and Prevention. There’s a lot you can do to live a lifestyle that lowers your risk.
D. Wiebers, Stroke-Free for Life, Cliff Street Books, New York, 2001; National Institute of Neurological Disorders and Stroke.