PHILADELPHIA – Migraine patients have an increased risk for subclinical brain lesions that sometimes resemble lesions found in patients with multiple sclerosis or cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, according to a population-based MRI study conducted in the Netherlands.
The presence of these lesions in migraine patients also raises controversial issues regarding the development of chronic migraine and potential prophylactic treatment, said Michel Ferrari, M.D., who discussed these issues in a presentation at the annual meeting of the American Headache Society.
In the CAMERA study, Dr. Ferrari, a neurologist at Leiden University Medical Center (LUMC) in the Netherlands, and his colleagues there and at the National Institutes of Health used MRI to identify brain infarcts and white matter lesions in 435 Dutch adults aged 34–63. The investigators compared the MRI images in three groups: 161 patients who had migraine with aura, 134 patients who had migraine without aura, and 140 controls without migraine.
They found a significant increase in subclinical deep white matter lesions in patients with migraine, compared with controls–most significantly, in women who had migraine with aura.
Questions raised by this study, according to Dr. Ferrari, include: Do the lesions cause any functional changes in migraineurs' brains? Are the lesions related to severity or chronification of migraines? How might this affect migraine treatment (if it is assumed there are progressive changes in the brain)? Can earlier, more aggressive migraine treatment lower the risk for lesions, thus lowering risk of the migraines becoming chronic?
As for the causes of the lesions, Dr. Ferrari mentioned multiple possibilities, including ischemia, cortical spreading depression, genetic factors, apoptosis, and, although unlikely, patent foramen ovale. Any of these could be contributing factors in causing lesions, he said, and they could also be comorbid conditions with migraines.
There is not enough evidence yet to indicate whether the migraines are causally related to the lesions or not.
Dr. Ferrari emphasized that a great deal of additional research is needed to address these issues and that no clinical recommendations can be made based on the results of the CAMERA MRI study. These need confirmation first.
“We worried that publishing this study would lead physicians to make a shortcut from lesions to treatment,” Dr. Ferrari said in an interview with this newspaper. “We should not treat a picture; we should treat a patient,” he cautioned.
Still, he said, clinicians should be aware of the issues and especially of the frequent confusion, on the part of physicians who are viewing MRIs, between migraine and other conditions–mainly multiple sclerosis.
If lesions are found, clinicians need to take a very careful history to figure out the cause of the lesions before making a diagnosis, he said.
In a related study, no difference in white matter lesions and infarcts was found between stroke patients with a history of migraines and those without migraine. (See sidebar.)
MRIs show (left to right) coexisting MS and migraine; migraine alone; and coexisting cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and migraine. Photos courtesy Dr. Michel Ferrari
Migraines: No Link to Lesions, Infarcts
There was no difference in the number and volume of white matter lesions or the number, location, and size of cerebral infarcts in stroke patients with a history of migraine compared to stroke patients without migraine, in an MRI study of 83 patients.
These results were reported by Hans Katzberg, M.D., of the University of Toronto, at the AHS meeting.
“We wanted to look at whether brain lesions in patients with migraine and stroke might be different, indicating a possible link between brain changes associated with migraine and an increased risk for stroke,” Dr. Katzberg said in an interview.
The results of the study did not indicate a general association. Still, he said, “our cohort did include a subgroup of migraine patients with stroke with no other obvious etiology, and these patients will be important to study further.”