CHICAGO – Ignoring mini-strokes has become a deadly game of denial, according to a new study that comes amid mounting evidence that transient ischemic attacks often forewarn of a full-blown stroke that might be prevented.

British researchers found that of 241 patients who had a documented mini-stroke, only 10 percent had gone to a hospital emergency room and less than half of the total group sought prompt medical care of any kind.

Although the study was conducted in England, stroke experts here said the findings should hold true for the United States, because most people and many doctors still do not realize that a transient ischemic attack is a strong warning sign that a disabling stroke is likely to follow.

Of the estimated 500,000 Americans who suffer first-time strokes each year, studies indicate that at least one out of five had a TIA beforehand. The new study, led by Dr. Matthew F. Giles of Oxford University, was reported Thursday in Stroke: the Journal of the American Heart Association.

People tend to ignore TIAs, experts say, because the symptoms disappear within a matter of minutes to hours, leading people to feel nothing is really wrong.

The attack occurs when blood flow to a particular part of the brain is temporarily cut off. The condition can cause sudden numbness or weakness of the face, arm or leg, especially on one side of the body; sudden trouble seeing in one or both eyes; sudden trouble walking, dizziness, loss of balance or coordination; or sudden, severe headache with no known cause.

“This basically quantifies how poorly educated the public is and probably quantifies the behavior we all know exists, which is that people tend to ignore stroke symptoms with this fantasy idea that it’ll go away and they’ll feel better in the morning,” said Dr. Jeffrey Frank, director of the University of Chicago’s neurointensive care unit.

The same mechanism that underlies a TIA – such as cholesterol-clogged arteries or a tendency to form clots – also can cause subsequent serious strokes, he said.

“A TIA isn’t something different than a stroke. It’s a stroke where people get fully better,” Frank said. “Getting better does not make it any less of an emergency than someone who’s had a stroke that isn’t getting better. In fact, the person who gets better from a TIA is the person in whom you can prevent disability the most by understanding what caused that TIA and figuring out the best strategy to prevent a recurrence.”

About 10 percent of people who have a TIA will have a stroke sometime in the next three months and approximately 20 percent will have a stroke within a year, said Dr. Michael Hill, a stroke neurologist at the University of Calgary in Canada.

The true percentage is probably higher, he said, because many people who suffer a major stroke are unable to remember if they had a prior incident.

“Of the patients who recover, at least a third will tell you, “Oh yeah, last week I had this spell and it got better so I ignored it,”‘ Hill said. “Then, of course, they come in with a big stroke a few days or week later. You just shake your head and wish you could have seen them when they had their first TIA because more often than not you can do something to prevent the stroke.”

Preliminary findings from an ongoing study at the University of Calgary indicate that when people arrive at the emergency room with a TIA and are fully evaluated and treated during a 24-hour workup, their risk of suffering a subsequent stroke is reduced by 50 percent, Hill said.

The main cause of stroke is blockages in the carotid arteries located on either side of the neck, which supply blood to the brain. Debris from the blockages can break off and plug smaller arteries downstream, or clots that form from the blockage can cut off blood flow.

“If you can identify a carotid artery blockage after a TIA and get that patient operated on and clean out that artery quickly, you effectively reduce their stroke risk to near zero,” Hill said.

The second biggest cause of stroke is clot formation in the heart because of irregular heartbeats, a condition known as atrial fibrillation. Clots circulate to the brain and plug arteries, depriving brain cells of oxygen. These patients are usually given blood-thinning medications to prevent clot formation.

For someone like Stroger, whose stroke was caused by a complete blockage of a narrowed artery deep in the right side of his brain, TIAs might allow physicians to discover the blockage and open it up with angioplasty, the same procedure used to open clogged heart arteries, Frank said.

Stroger, who is in Rush University Medical Center, has been treated with drugs to lower his cholesterol level and control his high blood pressure and diabetes. He already had bypass surgery for heart disease.

“A lot of times what keeps patients from seeking medical attention after a TIA is this notion that they want to see if it’ll get better,” Frank said. “Now, if someone gets a crushing chest pain they tend not to think that way. They know that if they get to a hospital it can be the difference between surviving and not surviving. People need to think the same way about a TIA.”