(707) Molecular Mimicry. It’s an Infection? No. It’s a Parainfectious Process? No. It’s MOGAD!

Introduction: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a CNS disorder involving immune-mediated demyelination targeting optic nerves, brain and spine

Description: 27yr old man with no medical history presents to the E.R. with headaches, fevers, malaise with urinary retention and was admitted for work up. Over the next few days, he developed worsening encephalopathy and was intubated. MRI spine showed diffuse increased T2 hyperintensity in C3-T11. MRI brain showed bilateral parietal, temporal, insular and occipital FLAIR hyperintensities and punctate diffusion restricted lesion in the frontoparietal lobes concerning for inflammation. He was started on empiric antimicrobials for meningoencephalitis. LP showed lymphocytic pleocytosis, low glucose, high protein, negative cultures. His neurologic exam worsened with progression to coma, bilateral vertical nystagmus, flaccid paralysis and quadriplegia. EEG showed generalized slowing, no seizures. CSF meningitis/encephalitis panel yielded positive EBV PCR. CSF/serum studies for autoimmune/paraneoplastic encephalomyelitis showed elevated CSF-MOG-IgG with an immunoglobulin-binding-index of 31.18 ( < 2.5) and titer 1:1024 ( < 1:2) concerning for MOGAD. EBV was the likely immune trigger. Treatment included steroids, plasmapheresis, IVIG and tocilizumab. After a complicated course over several weeks including tracheostomy, he showed some recovery. He was able to move his hands in bed, speak in short phrases, follow commands and was weaned off the ventilator. He was discharged to acute rehab

Discussion: When work-up of febrile encephalopathy is negative, differentials must expand to include autoimmune process like MOGAD. It can present with optic neuritis, disseminated encephalomyelitis, transverse myelitis, motor/sensory deficits or seizures. It is considered an autoimmune disorder of the CNS, triggered by an environmental stimulus in the genetically susceptible. Myelin autoantigens could share antigenic determinants with those of an infecting pathogen. The antibody response to the pathogen cross-reacts with the myelin autoantigens, resulting in disease. MRI with MOG serum/CSF antibody tests help to confirm diagnosis and rule out differentials. Treatment involves steroids, IVIG, PLEX with steroid-sparing agents in relapsing disease