High fever in myelin oligodendrocyte glycoprotein-associated disorder (MOGAD): A diagnostic challenge.

The phenotypic spectrum of myelin oligodendrocyte glycoprotein (MOG)-IgG associated disorders (MOGAD) has broadened in the past few years, and atypical phenotypes are increasingly recognized. Febrile meningoencephalitis has rarely been reported as a feature of MOGAD and represents a diagnostic challenge. We report the case of 24-year-old women with high-grade fever, meningoencephalomyelitis, and persistently positive MOG-IgG, for whom an extensive infectious work-up was negative and who responded to high-dose intravenous methylprednisolone. The full clinical spectrum of MOGAD is yet to be completely elucidated. In patients presenting with febrile meningoencephalitis, MOG-IgG testing should be considered particularly if infectious work-up is negative.