(NEW YORK) -- A transient ischemic attack, or TIA, occurs when symptoms of a stroke come and then go away within 24 hours. The cause is often a clot in a vessel in the brain that temporarily blocks blood flow.
What makes TIAs and minor strokes so dangerous is that many who experience symptoms ignore them after they go away -- even though they may have experienced some degree of brain damage and are also at a higher risk for a full-blown stroke.
Now, new research suggests that in roughly one out of eight cases in which people experience major disability from TIA and minor stroke, the first occurrence of symptoms was their only warning sign that something was wrong.
A team of Canadian researchers monitored 510 people who experienced "mini strokes" -- a label doctors use to describe TIAs and minor strokes that involve mild and/or transient symptoms. These patients' initial symptoms were recorded and rechecked at 90 days with repeat brain imaging and measured level of disability.
What the researchers found was that 12 percent of patients who had the initial "mini stroke" had worsened disability in the next 90 days -- even if they had experienced no repeat events after their initial one.
The research was published Thursday in the American Heart Association's journal Stroke.
"Patients need to get in quickly even if symptoms have resolved or are resolving," said lead study author Dr. Shelagh B. Coutts, assistant professor at Hotchkiss Brain Institute Calgary in Canada. "We like to identify those at highest risk of disability."
Symtoms of a TIA are exactly the same as for a stroke, according the the American Heart Association, and include:
- Numbness -- Sudden numbness or weakness of the face, arm or leg, especially on one side of the body.
- Confusion -- Sudden confusion, trouble speaking or understanding.
- Trouble Seeing -- Sudden trouble seeing in one or both eyes.
- Dizziness -- Sudden trouble walking, dizziness, loss of balance or coordination.
- Headache -- Sudden, severe headache with no known cause.
Stroke experts not involved with the study said the findings are an important reminder that stroke symptoms, even if they don't linger, must be taken seriously.
"TIA is to stroke what chest pain is to heart attack," said Dr. Fadi B. Nahab, medical director for the stroke program at Emory University Hospital in Atlanta. "People have a better understanding of chest pain and go the emergency room, whereas [they believe] symptoms for TIA must be something else."
"[People who have a TIA] have won the stroke lottery," said Dr. Steven Cramer, clinical director of the stem cell research center at the University of California, Irvine. "They found out there is something wrong without having to pay the big stroke price."
The findings, in fact, were so alarming that the study authors suggested that doctors should consider administering the clot-busting medicine known as tissue plasminogen activator, or tPA, for patients who show up at the hospital after a TIA or minor stroke.
"If patients have symptoms that are mild, we are even currently doing a study to use thrombolysis, in those cases," she said.
Currently, tPA is only indicated for use in patients experiencing full-blown stroke. But as for whether the benefits of this medicine outweigh its risks in patients experiencing mini strokes, most doctors say more research is needed.
"There is no evidence at all that treating TIA acutely with tPA would make any difference," said Dr. Jeffrey M. Katz, director of the stroke center and stroke unit at North Shore University Hospital in Long Island, N.Y. "I think that many times we decide not to treat patients with minor symptoms from stroke because of the risk for bleeding with tPA and the thought that these patients will do well anyway."
But, Katz adds, "this is probably one of the largest studies to say that these patients may not do well ... Of course it says nothing about whether they would do well with tPA, but I think it certainly suggests that they aren't doing better if left untreated."
Copyright 2012 ABC News Radio