MOGAD headache or migraine: when, what and how to recognise?

<h3>Background</h3> Anti-myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a central nervous system inflammatory autoimmune condition often affecting the optic nerves, spine and brainstem. Headache as the primary presenting feature of MOGAD is not commonly recognised, potentially causing delay/misdiagnosis. We present a case of ‘MOGAD headache’ as the primary presentation, identifying clinical features to help make the MOGAD diagnosis for Headache doctors. An 18-year-old male presented with 6-days bifrontal stabbing headache, photophobia and morning vomiting without infective-prodrome. Neurological-neuroophthalmological examination was normal. Acute migraine was initially diagnosed. He represented with similar persistent headache and binocular visual blurring. Re-examination revealed bilateral reduced visual acuity, dyschromatopsia and bilateral optic nerve dysfunction. Contrast MRI showed leptomeningeal enhancement and bilateral optic neuritis. CSF was lymphocytic with negative meningitis/encephalitis array and negative oligoclonal-bands. MOG-antibody serology was positive. Visual-Evoked-Potentials confirmed bilateral optic nerve dysfunction. Symptoms improved following 5-days intravenous methylprednisolone. <h3>Discussion</h3> Binocular visual disturbance is common in migraine and misattribution to aura is not uncommon. Appropriate clinical assessment of anterior visual pathway function is essential to avoid missing rare secondary headache disorders, e.g. MOGAD meningitis with visual disturbance mimicking status migrainosus. Headache at onset of MOGAD is not well-defined but may mimic migraine as the common initial misdiagnosis.