A case of anti-myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin G (IgG) associated disorder (MOGAD) with clinical manifestations of acute disseminated encephalomyelitis: Secondary to mycoplasma pneumoniae infection.

Anti-myelin oligodendrocyte glycoprotein (MOG)-immunoglobulin G (IgG) associated disorder (MOGAD) is an immune-mediated central nervous system (CNS) inflammatory demyelinating disorder that has been widely recognized in recent years. It is distinct from multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), which are separate disease spectrums. Here we report the case of a 5-year-old boy who was admitted for 3 days with fever, headache, and vomiting. Magnetic resonance imaging revealed abnormal hyperintensity in the left thalamus and positive serum IgM for M. pneumoniae. After treatment with azithromycin, the headache gradually disappeared, but paralysis and urinary retention occurred on the 6th day after admission. MRI re-examination showed that the original abnormal signal in the left thalamus was significantly weakened, but new abnormal signals appeared in the brain and cerebrospinal cord, and the serum MOG-IgG was positive. After treatment, the child has fully recovered and is still receiving follow-up care. We believe that this is a case of MOGAD in a child with a biphasic ADEM phenotype secondary to M. pneumoniae infection, which has potential value in elucidating the pathophysiology of MOGAD.