A case of anti-MOG antibody-positive unilaterally dominant meningoencephalitis followed by longitudinally extensive transverse myelitis

Background: There are few reports of anti-myelin oligodendrocyte glycoprotein (MOG) antibody-positive, unilaterally dominant cerebral cortical encephalitis onset with epilepsy. We present such a case in a young female patient with myelitis. Case presentation: A 19-year-old female developed generalized tonic seizures lasting several minutes. She had a low-grade fever and headache without other clinical neurological abnormalities while at our hospital. Cerebrospinal fluid (CSF) showed mononuclear pleocytosis. Other laboratory tests indicated no apparent abnormalities. Unilateral meningeal hyperintensity was seen on T2 fluid-attenuated inversion recovery MRI with associated cortical swelling and gadolinium enhancement of the cortical layer. One thousand mg/day of levetiracetam and a 3-day course of intravenous methylprednisolone at 1000 mg/day were administered. Dysuria appeared on the twentieth day of illness, and spinal MRI revealed a longitudinally extensive cord lesion from C5 to L1 consistent with myelitis. Two cycles of a 3-day course of intravenous methylprednisolone at 1000 mg/day were administered, and all symptoms disappeared. We found the patient to be anti-MOG antibody-positive using serum and CSF (titer: serum 1: 256; CSF 1: 128). Conclusion: Our report illustrates a unique case of anti-MOG presenting as new onset epilepsy secondary to unilaterally dominant meningoencephalitis preceding the onset of longitudinally extensive transverse myelitis.