Our patient first developed symptoms in 2017 at age 83, after 10 days of sudden left flank numbness with left leg weakness and numbness. Thoracic spine MRI showed contiguous cord enhancement from T2-T6. No enhancing lesions were seen within the brain or cervical spine. Lumbar puncture was negative for oligoclonal bands and IgG. Further workup was negative for other demyelinating, infectious, and inflammatory etiologies. The patient received plasma exchange and high-dose steroids before being transferred to acute rehab where she regained ambulation with assistance but had persistent urinary retention. The patient presented again in 2021 with new onset right flank numbness, right leg weakness and numbness for 3 weeks. Repeat MRI of the thoracic spine showed new cord enhancement from T3-T6. AQP4 antibody was positive at 1:10,000. The patient underwent similar treatment with plasma exchange, high-dose steroids and was transferred to acute rehab.

Advanced age and delayed diagnosis are independent risk factors for worse prognosis for NMOSD. “Late-onset” NMOSD patients have increased risk of disability, poor response to treatment, and an increased risk of mortality. Therefore, it is imperative to consider NMOSD regardless of age as delayed diagnosis can lead to subsequent relapses and fatal outcomes.