An Unusual Case Presentation of MOG-Positive Acute Disseminated Encephalomyelitis (ADEM) in a Preschool Child

ABSTRACT

Introduction: An unusual case presentation of MOG-positive Acute Disseminated Encephalomyelitis (ADEM) in a preschool child following meta-pneumo viral infection responded to the combination of immune modulatory treatment with a favourable outcome. Material: Three-year-old female child presented with acute encephalopathy, high fever, vomiting, starring episodes, floppiness, and left abducent nerve palsy with rapid deteriorating GCS necessitating intubation and ventilation. Two weeks earlier, she was treated for suspected CNS infection with 10 days of antibiotics in the PICU with a positive meta-pneumo-virus. On admission, she had a GCS score of 6 with left-sided increased tone, bilateral hyperreflexia, and bilateral extensor response and on Day 14 demonstrated hyperkinetic movements of the upper and lower limbs. Method(s) Serum MOG antibody positive, CSF MOG low positive, metabolic investigations, Mycoplasma, EBV, Influenza, corona PCR, SARS-COV-2 Antibody, viral CSF panel unremarkable. MRI brain demonstrated T2 hyperintense signal in bilateral medial thalami and brain stem with a normal spine. Progressive changes were shown on repeated MRI Brains on day 4 and day 14 suggestive of multifocal changes involving deep cortical and subcortical white matter bilaterally with a new short segment of the spinal lesion at the T8 level. Repeated EEG and ambulatory EEG showed a diffusely slow background with intermittent slow runs of slow waves suggestive of generalized cerebral dysfunction. Result(s) After receiving the combination of high pulse steroids with a taper over 10 weeks, IVIG and 10 cycles of plasmapheresis she demonstrated gradual and remarkable clinical improvement over 10-12 weeks with a minimal focal neurological deficit. Conclusion(s) Initial differentiating CNS infection, metabolic disease and ADEM may be clinically challenging. Her clinical presentation, investigations and imaging were in keeping with the diagnosis of MOG-positive ADEM. Previous CNS infection may be related. MOG-positive ADEM treated with the early combination of immunomodulation may lead to positive clinical outcomes.