Chronic migraine with medication overuse pre-post withdrawal of symptomatic Medication: Clinical results and fMRI correlations

Background. - Chronic migraine with symptomatic medication overuse (CMwMO) is a common and often debilitating clinical condition. Withdrawal of the offending drug(s) is considered the first step in management. Functional magnetic resonance imaging (fMRI) may be a useful technique for obtaining information on particular neuronal changes in the pain network involved in this condition. Objective. - To identify specific fMRI patterns in patients suffering from CMwMO before and after withdrawal intervention. Methods. - We collected fMRI data from a group of patients suffering from CMwMO, evaluating those patients prior to and 6 months following withdrawal. We applied stimuli at sites far removed from where the headaches were experienced. Moreover, pre-intervention fMRI data from the headache patients were compared with those obtained from headache-free and otherwise healthy controls. Results. - Before withdrawal, the right supramarginal gyrus, the right inferior and superior parietal cortex were hypoactive. Activity recovered to almost normal 6 months after withdrawal of the offending medications. Conclusions. - The hypoactivation we detected in the lateral pain system indicate that there exists a modification of the pain network in CMwMO and that these changes are reversible with therapy.