Very late-onset neuromyelitis optica spectrum disorder: differences and difficulties at 96 years-old

• This case report describes a rare instance of Neuromyelitis Optica Spectrum Disorder (NMOSD) in a 96-year-old woman, emphasizing the challenges and distinct clinical features associated with managing NMOSD in an extremely elderly patient population. • The patient's advanced age, coupled with comorbidities, complicated the diagnosis and treatment, requiring cautious use of immunosuppressive therapies, balancing efficacy and safety in very late-onset NMOSD (VLO-NMOSD). • VLO-NMOSD seems to exhibit prolonged intervals between relapses but an overall poorer outcome. • There is a growing need for deeper understanding of the neuroimmunology of aging, especially its impact on disorders that are well-characterized in younger populations. Neuromyelitis Optica Spectrum Disorder (NMOSD) is an immune-mediated inflammatory condition affecting the central nervous system, predominantly impacting the optic nerve and spinal cord. Though typically occurring between 30-40 years, the rising incidence of late-onset cases, especially beyond age 70 (VLO-NMOSD), necessitates attention. Limited literature exists on VLO-NMOSD, contrasting with onset between 50-70 years (LO-NMOSD). As the elderly population expands, understanding VLO-NMOSD becomes crucial due to increased comorbidities, complex medication regimens, altered immune responses, and management challenges. A 96-year-old woman presented with hiccups, vomiting, constipation, urinary incontinence, paresthesia, and weakness progressing subacutely. Diagnostic delay occurred despite an MRI revealing longitudinally extensive central cord myelopathy, involvement of the anterior medulla, area postrema, left cerebellum, and lesions in periventricular cerebral white matter. Positive anti-aquaporin-4 antibodies were found in serum and cerebrospinal fluid. Treatment with intravenous methylprednisolone and immunoglobulin yielded minor improvement, maintaining flaccid quadriparesis and low left visual acuity. Prednisone was tapered, and azathioprine initiated due to safety concerns. No relapses occurred post-treatment. This case highlights management challenges in VLO-NMOSD, emphasizing the importance of understanding this age-specific population for improved clinical care. Despite age-related complications, VLO-NMOSD exhibits fewer relapses with longer intervals and subacute presentations. A nuanced approach involving comprehensive investigation, age-specific trials, and personalized treatment strategies focused on symptomatic management is vital for advancing NMOSD management across all age groups.