Arkink EB, Terwindt GM, de Craen AJM, Konishi J, van der Grond J, van Buchem MA, et al. Infratentorial Microbleeds: Another Sign of Microangiopathy in Migraine. Stroke. 2015
Migraine with aura is a proven risk factor for ischemic stroke. Migraine is also a phenotypic manifestation of several genetic vasculopathies like CADASIL which primarily affect small intracranial vasculature. The temporal cause-effect relationship between migraine and small vessel disease however is difficult to clearly elucidate. Migraine has been associated with small vessel endothelial damage and hypercoagulability which may lead to small vessel disease. On the other hand, microcirculatory vasoconstriction during cortical spreading depression leads to migraine headaches. Regardless of which came first, their is no denying their coexistence.
Migraine has been associated with white matter hyperintensities on MRI in several studies. Cerebral microbleeds(CMBs), especially in subcortical structures is also thought to be associated with small vessel disease leading to Charcot-Bouchard aneurysms and subsequent rupture.
In the current study by Arkink et al, the authors looked at data from the PROSPER MRI database and used a validated headache questionnaire to identify 63 migraineurs out of 506 patients. A couple of authors scored CMBs and classified them into lobar, basal ganglia and infratentorial.
They found no difference in the overall prevalence of CMBs between migraineurs and controls, but there was a borderline statistically significant difference in infratentorial CMBs in patients with migraine without aura vs controls (14% vs 4%, p 0.048). Also, migraineurs with CMBs were more likely to have infarcts and vice versa. Apart from the small sample size of migraineurs, the main drawback of the study is that hypertension was more common among migraineurs as compared to controls, which may have driven the findings as a confounder. One also has to remember that this cohort includes patient aged 73-85 years, and so any effect of migraine on CMBs may be lost in the noise generated from underlying high prevalence of cerebrovascular risk factors. Regardless, this study proves again that there seems to be an association between migraine and infratentorial microcirculation. Problem is, we still don’t know which came first.