[Anti-myelin oligodendrocyte glycoprotein antibody-positive unilateral cerebral cortical encephalitis occurring first as general convulsion after meningitis symptoms and second after headache].

The case was a 30-year-old man. He had generalized convulsion after preceding meningitis symptoms and transferred to our emergency department. He was tentatively diagnosed with meningoencephalitis and Todd paralysis based on elevation of cell counts in cerebrospinal fluid and abnormal high signals in the right cerebral cortex on brain FLAIR-MRI, and admitted on the same day. After admission, treatment with antibiotics, dexamethasone, antiviral drug and anticonvulsants was started. Both his clinical symptoms and findings on MRI improved steadily, and then he was discharged on day 19. Subsequently, headache exacerbated again and an additional examination for his serum sample taken on first admission day revealed presence of anti myelin oligodendrocyte glycoprotein (MOG)-antibody, resulting in his diagnosis of anti-MOG antibody unilateral cerebral cortical encephalitis (MOG-UCCE) on day 42. Rehospitalization was planned for introduction of steroid therapy, but generalized convulsion recurred on day 44 and he was hospitalized again. MRI image revealed no FLAIR high signal and cerebrospinal fluid was almost normal, but his headache and mild hemiparesis and numbness on the left side deteriorated again. Therefore, he was treated with intravenous high dose methylprednisolone followed by oral steroids. His clinical symptoms gradually improved, and he was discharged with slight headache on day 71. After discharge, there has been no recurrence under continuation of low dose oral steroids for two years. This case shows the need to measure anti-MOG antibody and introduce steroid therapy in the early phase in a case of suspected MOG-UCCE in a young patient with meningoencephalitis accompanied by generalized convulsion and characteristic abnormal findings on FLAIR-MRI.