When someone suffers a stroke, neurons begin to die just minutes after a blocked artery cuts off oxygen to a part of the brain. But in some patients, damage continues to spread to nearby brain areas for as long as a day after the stroke. Now researchers have identified one risk factor for a "progressing" stroke: high blood levels of iron.
Earlier clues suggested that iron exacerbates stroke damage. Patients with copious amounts of ferritin, a protein that binds and stores iron, in their blood had more brain damage, such as paralysis and speech defects, 1 month after a stroke. And animal studies linked iron to excess fluid buildup after brain injury, which can damage more neurons, as well as to the production of destructive compounds called free radicals.
To investigate iron's role more closely, neurologist Antoni Davalos of the Hospital Universitari in Girona, Spain, and colleagues examined samples of blood and cerebrospinal fluid from 100 stroke patients admitted to the hospital in 1992 through 1996. Compared to patients with low ferritin levels, those with high levels were 33 times more likely to have their condition deteriorate in the 24 hours following a stroke, the researchers report in the 25 April issue of Neurology.
Dennis Choi, a neurologist at Washington University in St. Louis, says it's premature to treat stroke patients with compounds that remove iron from the bloodstream, but he says the results are intriguing and that "high ferritin levels in stroke patients might be an important clinical warning sign" that the patients' condition could continue to worsen after a stroke.