Migraine attacks may add to risk of strokes
Doctors warn some migraine attacks may prompt permanent changes in the brain, although the implications remain uncertain
That head-splitting migraine attack that knocks you off your feet may also put you at risk of permanent changes in the brain, an analysis of 19 medical studies found.
The potential for increased abnormalities in the signalcarrying white matter of the brain appears strongest among those who suffer headache warning symptoms, such as flashes of light, blind spots and tingling, according to the analysis published online on Wednesday in the journal Neurology. Those "migraine with aura" sufferers were about 1.7 times as likely to have such anomalies than were the non-migraine population, the analysis found.
But the significance of these white-matter blips and other tissue changes remains elusive, and there is some question about whether the neurological variances from the norm mark a migraine-prone brain or the ravages of the attacks, researchers said.
At best, doctors have concluded that what they see on patients' magnetic resonance imagery amounts to a "benign imaging correlate" of migraine. They're there, they are associated with migraine, and that's where the hard evidence stops.
"Part of the message I hope to communicate here is: If you have migraine with aura and you have white-matter lesions, they're probably not a cause of concern," said study coauthor Dr Richard B. Lipton, a neurologist who heads the Montefiore Headache Centre in the Bronx, New York.
Migraine headaches affect 10 to 15 per cent of the population, and about a third of those experience aura symptoms, according to the study. The symptoms can cause substantial impairment and hardship, including lost work hours and high medical costs.
Although research centres have sprung up at medical centres such as Montefiore, methods of studying the malady have varied enough that a comprehensive analysis of data proved difficult.
Still, enough data has accrued to recommend therapies that reduce the incidence of migraine, particularly among those with aura symptoms who may also have additional risk factors for stroke, Lipton said. Other studies have suggested that those who suffer from migraine with aura have twice the risk of a stroke, Lipton noted.
"If you have migraine with aura, certainly you shouldn't smoke," Lipton said. "Certainly, if you are going to use oral contraceptives, you should use the lowest possible hormonal dose. If you have other stroke risk factors such as hypertension or diabetes or high cholesterol, it becomes particularly important to manage those risk factors."
But the inconclusive nature of the analysis leaves big questions unanswered, said Peter Goadsby, a neurologist who heads headache lab at the University of California, San Francisco, and who was not involved in the analysis. "A meta-problem with the area," he said, "is people with migraine don't die. That's good, because people not dying is very good. However, it does limit what you say if you can't see what the pathology is. And therein lies the problem."
Studies of the tiny lesions that have the appearance of a stroke scar proved mostly inconclusive. And the analysis turned up no significant evidence of cognitive decline or other neurological symptoms from such lesions or other whitematter anomalies. Whether these lesions are evidence of undiagnosed mini-strokes remained unclear as well.