A case series of adults with MOGAD encephalitis

<h3>Background</h3> MOGAD encephalitis is a recently described, rare manifestation of MOG-antibody associated disease. Risk of relapse and optimal treatment strategies remain unproven. <h3>Aim</h3> We set out to describe the largest cohort of adult patients presenting with MOGAD encephalitis to date. Relapses, treatments and ongoing immunomodulatory strategies were captured. <h3>Methods</h3> Data on consenting patients, aged 16 to 40, with clinically and radiologically diagnosed MOGAD encephalitis were collected using national NMOSD clinical networks. <h3>Results</h3> Seven patients were included. All had generalised seizures; four had focal seizures. One patient was encephalopathic and four displayed focal neurologic deficits at presentation. All patients had MRI FLAIR hyperintensities; four had cerebral swelling and one had leptomeningeal enhancement. CSF pleocytosis was seen in 4/5 patients (8 – 25) with raised protein in 2/5. Interictal EEG was normal where performed. Five patients received methylprednisolone and all patients received anti-epileptic drugs. All had symptom resolution; time to seizure control was 0.25 to 7 months. Three patients had clinical relapse. Two experienced optic neuritis: one soon after treatment for seizures and one 24 years after seizure onset. Another patient experienced seizures and area postrema syndrome in a 3 year period after symptom onset. <h3>Conclusions</h3> This case series describes seven patients with MOGAD encephalitis. Three patients experienced subsequent clinical relapse, highlighting the need for ongoing clinical monitoring and potential use of immunomodulatory treatment in this cohort.