A Case of Neuromyelitis Optica Spectrum Disorder

Introduction: We present a case of neuromyelitis optica spectrum disorder (NMOSD), previously known as neuromyelitis optica (NMO) or Devic Disease. NMO was classically described as a triad of optic neuritis, longitudinal myelitis, and a positive anti-AQP4 antibody, however a far wider range of presentations are now recognized and so the term NMOSD is now used. NMOSD is a severe demyelinating disease caused by an autoantibody to the aquaporin-4 water channel. It is a relatively rare disorder with a prevalence ranging from 0.5-10 per 100,000. This case highlights presenting signs/symptoms, imaging findings, and management for NMOSD. Case presentation: A 71-year-old female presented with an episode of right arm weakness and ataxia. The initial stroke workup was negative. Subsequent imaging demonstrated classic findings of NMOSD: a longitudinally extensive spinal cord lesion, optic neuritis, and nonspecific T2/FLAIR white matter hyperintensities in the brain. Furthermore, the patient tested positive for the aquaporin-4 antibody and CSF analysis was negative for oligoclonal bands. The patient was started on a 5-day course of methylprednisolone and transitioned to rituximab for chronic treatment of NMOSD. Discussion and Conclusion: This case report demonstrates a relatively rare disorder that can present under the guise of more common pathologies such as stroke or multiple sclerosis. It also highlights key lab and imaging findings to distinguish it from similar disorders. Despite this being a relatively rare disorder, this case shows a classic presentation, lab values, and imaging findings to help guide the diagnosis and treatment of NMOSD to improve patient outcomes