Myelin Oligodendrocyte Glycoprotein Encephalomyelitis

Abstract

Background: Myelin oligodendrocyte glycoprotein encephalomyelitis (MOG-EM) includes patients with (i) monophasic or relapsing acute optic neuritis, myelitis, brainstem encephalitis, or encephalitis; (ii) magnetic resonance imaging (MRI) or electrophysiological evidence of central nervous system (CNS) demyelination; and (iii) MOG-immunoglobulin G (IgG) seropositivity. Clinical Description: A 4-year-old girl presented with fever and excruciating headache for 10 days. Her vitals were stable and systemic examination was normal. Cerebrospinal fluid (CSF) analysis revealed 10 lymphocytes and normal biochemistry. After 5 days, she developed a fever and a seizure. Repeat CSF showed increased cells (60% lymphocytes), normal protein, and sugar. MRI brain was normal. She was managed symptomatically. CSF meningoencephalitis panel was negative. The child improved and was discharged. After 2 weeks, the headache recurred with associated blurring of vision. Bilateral papillitis, MRI brain abnormalities suggestive of acute disseminated encephalomyelitis (EM), and bilateral prolonged latency on visual evoked potential (VEP) were found. Anti-MOG antibodies were positive. The final diagnosis was MOG-EM. Management: The child was started on methylprednisolone therapy as per standard protocol. The vision improved and headache disappeared. She is on regular follow-up and is asymptomatic. Conclusion: MOG-IgG testing should be done in patients with (i) monophasic or relapsing acute optic neuritis, myelitis, brainstem encephalitis, or encephalitis; (ii) radiological or VEP findings compatible with CNS demyelination; and (iii) at least 1 of 25 delineated findings on MRI, fundoscopy, CSF, histopathology, clinical phenotype, or treatment response.