Vestibular Migraine-Overlapping Syndrome Refractory to Several Treatments Eventually Responding to Calcitonin Gene-Related Peptide (CGRP)-Targeted Therapy : A Case Report

A 50-year-old woman visited a neighborhood hospital with a one-year history of paroxysmal dizziness and right-sided hearing loss recurring at least once a month and lasting for approximately 5 hours each time. Recently, the frequency of dizziness had increased to once a week, with the symptom lasting for approximately 7 hours each time. The patient experienced seizures, and had lost 5 kg of body weight. She was treated for right-sided Meniere's disease at another hospital, but as there was no improvement, she was referred to our department. At the first consultation, she had only mild hearing loss in the right ear. However, a pure-tone audiogram recorded during an episode of dizziness showed low-tone sensorineural hearing loss on the right side. Contrast-enhanced MRI of the inner ear revealed vestibular endolymphatic hydrops on the right side. No difference in the cVEMP was observed between the right and left ears. Based on the findings, the patient was diagnosed as having right-sided Meniere's disease with vestibular migraine (vestibular migraine-overlapping syndrome, VMOS). While two courses of intraventricular dexamethasone administration failed to have any therapeutic effect, intraventricular gentamycin administration clearly suppressed the dizziness. however, the patient continued to suffer from migraine and dizziness more than 10 times a month. Finally, subcutaneous administration of a human anti-CGRP receptor monoclonal antibody (erenumab) reduced the frequency of headache and dizziness. Patients with VMOS present with intractable dizziness. Anti-CGRP receptor monoclonal antibody could be effective for treating VMOS. Continuity of treatment and concomitant treatments should be further discussed with headache specialists.