White matter lesions in chronic migraine with medication overuse headache: a cross-sectional MRI study.

Analgesic overuse often happens to migraine patients, especially chronic migraineurs, and migraine has been demonstrated to be associated with white matter lesions (WMLs). The aim of this study was to investigate the relationship between medication overuse headache (MOH) and WMLs in chronic migraine (CM) patients. Subjects were enrolled and divided into three groups: healthy controls, CM without MOH (CMwoMOH), and CM with MOH (CM-MOH). Most of the CM patients used non-steroidal anti-inflammatory drugs (NSAIDs) as acute headache medications. All the participants underwent magnetic resonance imaging scans and images were obtained for WML evaluation with semiquantitative scales. One hundred and forty-one participants were included, 45 of them for controls, 38 for CMwoMOH, and 58 for CM-MOH. In women, CMwoMOH patients had a higher prevalence of high WML load compared with controls and CM-MOH patients. In men, however, all the study groups showed no differences in the prevalence of high WML load. CMwoMOH women had increased risks of high deep white matter lesion (DWML) load compared with controls, while they had no risks of high periventricular white matter lesion (PVWML) load. CM-MOH women had no risks of high DWML load, but they had reduced risks of high PVWML load. The association of CM-MOH with high WML load in women was not changed when compared with CMwoMOH. Age was independently associated with high WML load among women. These data suggest that MOH caused by NSAIDs is not a risk factor for WMLs. Rather, NSAID overuse probably protects MOH patients from WMLs through anti-inflammatory effects.