Microbleeds and Strokes
Microbleeds, pinpoint drops of blood that are leaked from blood vessels in the brain, cause some concern for doctors – especially in patients who have suffered from a stroke. After a stroke, doctors frequently prescribe anticlotting drugs, however if a patient also has microbleeds, it could cause a whole new problem – turning a “microbleed into a life-threatening, incapacitating hemorrhagic stroke” reports Gina Kolata in the New York Times.
Until recently, microbleeds were all but unknown. Now, with improved scans, they are turning up constantly; one recent study found them in the brains of 1 out of 5 people age 60 and older. And they are leading to a classic conundrum of modern medicine: Just because something turns up on an M.R.I. scan, is it significant? And if it may or may not be significant, what to do about it?
According to Dr. Greenberg microbleeds located on the outer surface of the brain appear to be linked with a condition in which blood vessels are damaged by the protein amyloid, where as microbleeds deep in the brain may be linked to high blood pressure. “But it is not clear whether microbleeds, especially those deep in the brain, are of any real consequence” (Kolata, 2008).
Recently Dr. Monique M.B. Breteler, a nueorepidemiologist at Erasmus University in Rotterdam, the Netherlands, has been researching the frequency of microbleeds in health people. According to Dr. Breteler the results were surprising. “Previous estimates were that 5 to 7 percent of healthy older people had microbleeds. The Rotterdam study found them in more than 20 percent. And the older the person, the more likely the microbleeds. They were present in 18 percent of 60-year-olds and nearly 40 percent of those over 80” (Kolata). Kolata reports:
Dr. Greenberg has found that if the microbleed is near the brain’s surface, where it might be associated with amyloid, then anticlotting drugs are more likely to precipitate a brain hemorrhage. But sometimes a patient is at such grave risk of a stroke that the balance tips in favor of an anticlotting drug anyway, he says.
If the microbleed is deep in the brain, it is not clear whether anticlotting drugs are dangerous.