Very late-onset neuromyelitis optica presenting with simultaneous bilateral optic neuritis and myelitis: A case report

New-onset Neuromyelitis Optica Spectrum Disorder (NMOSD) has rarely been reported in adults over age 70. We describe a severe presentation in a 77-year-old female. The patient presented with left arm numbness, followed by left leg numbness and bilateral optic neuritis. Neuroimaging showed a C2-T1 lesion with C4-C7 holocord enhancement, and bilateral optic nerve enhancement extending to the optic chiasm. Serum testing detected anti-aquaporin-4 antibodies. She was left with dyschromatopsia, myelopathy, and ambulatory dysfunction. She had a history notable for rheumatoid arthritis, treated with rituximab, which had been discontinued six years prior to presentation. Very-late-onset NMOSD encompasses a unique cohort of patients with significant immunogenicity despite immunosenescence. Limited data suggest diagnostic delays, severe morbidity, and decreased utilization of disease-modifying therapies.