Maxy sez : Small Strokes Can Cause Big Damage

Under-detected "mini-strokes" cause brain damage, result in cognitive impairment, and dementia, says a new study.
By Jessica Firger
 Chances are if you're a senior managing your health, you've already had a conversation with your doctor about stroke risk. While many patients know the warning signs of stroke — slurred speech, weakness on one side of the body, coordination problems, double vision, and headaches — health care providers often fail to educate patients about their risk for silent or "mini-strokes," which can cause progressive, permanent damage and lead to dementia.

A new study published in the Journal of Neuroscience, examined the effects of these so-called mini-strokes. They frequently are not diagnosed or detected by a doctor because a patient does not immediately present with stroke signs. Mini-strokes may lead to permanent neurological damage and increase risk for full blown stroke.

Maiken Nedergaard, MD, lead author of the study and professor of neurosurgery at the University of Rochester Medical Center, says at least half of individuals over the age of 60 will experience one mini-stroke in their lifetime. She calls the prevalence of mini-strokes "an epidemic."

"Often you don't have symptoms. That's the scary thing about them, you don't know they're occurring," says Dr. Nedergaard. "If you are elderly and something doesn't work quite right, you think, I should take a nap. You don't go to the hospital unless you have big stroke."

Mini-strokes often are detected well after the damage has been done, she says, and quite possibly by the time a patient has had several of them. A typical scenario, says Nedergaard, may be a patient who visits her doctor for chronic migraines. The doctor may order an MRI to rule out brain tumors, only to discover the patient has had several mini-strokes, which appear on a scan as "little dots where the tissue has grown," she says.

"When you have a stroke, there's an area of the brain that dies rapidly almost at the epicenter of the injury, but there are neurons around it that die slowly," says Larry Goldstein, MD, professor of medicine, director of the Stroke Center at Duke University and a spokesperson for the American Heart Association.

The study authors say mini-strokes are similar in nature to ischemic strokes, which are full blown episodes provoked by a loss of blood supply, depriving an area of the brain from oxygen. Ischemic stroke effects, including blurry vision, numbness, and slurred speech, are usually present immediately after the event. "A big stroke is caused by a clot in the artery. We assume that's the same that happens in the mini-stroke, but it's not clear," says Nedergaard. "What we do know is they cause this very delayed loss of cells in the brain."

Nedergaard and her colleagues used rodents to examine the impact of small strokes. Strokes were provoked by injecting mice with cholesterol crystals, she says. The researchers put the mice who had mini-stroke through a series of tasks, such as recalling objects and responding to audio cues. They found the mice who suffered strokes were more likely to fail these tasks.

"Silent strokes are really common but their effects are not silent," says Philip B. Gorelick, MD, MPH, medical director of the Hauenstein Neuroscience Center of Saint Mary's Health Care in Grand Rapids, Mich. He says one in three patients who have a mini-stroke will sustain permanent damage.

According to the Centers for Disease Control, stroke is the third leading cause of death in the United States. They typically occur in people over the age of 65, and cause more than 140,000 deaths each year. Around 795,000 people suffer a stroke annually. About 600,000 of these are first attacks and 185,000 are recurrent attacks. Strokes are common among people with atrial fibrillation, high blood pressure, and smokers.

Nedergaard says currently there's no treatment available to reverse brain damage caused by a stroke or to lower a patient's chances for having recurring episodes or developing dementia. This is why preventative medicine is crucial.

To lower one's risk for having a stroke, doctors advocate for preventive medicine and a healthy lifestyle, which includes a low sodium and low cholesterol diet, a regular exercise program, only moderate amounts of alcohol, and not smoking cigarettes. Some doctors may recommend cholesterol-busting medications such as Plavix and anticoagulants such as aspirin.