Abstract
Background Neuromyelitis optica spectrum disorder (NMOSD) is an astrocytic disorder of the central nervous system. Onset of NMOSD beyond the age of 60 accounts for 20–28% of all incident NMOSD and is associated with a poor prognosis. Approximately 15–40% are seronegative for NMO and MOG antibodies.
Case Presentation An 80 year old male of Cantonese ethnicity initially presented to hospital with three weeks of progressive lower limb weakness which eluded diagnosis at an overseas tertiary hospital. Previously independent in mobility, he presented with a flaccid paraparesis, incontinent, with a largely preserved sensory examination. Past medical history included a thyroidectomy and metallic aortic valve replacement. MRI demonstrated longitudinally extensive transverse myelitis from C3 to conus medullaris predominantly affecting ventral cord. Aquaporin-4 and MOG antibodies were negative, along with an extensive CSF, serum and imaging work up for potential inflammatory, autoimmune, malignant and infective causes.
T2 MRI Sagittal Cervical Spine:
He was treated with five days 2g/kg intravenous immunoglobulin, three days IV pulse methylprednisolone, tocilizumab (anti IL-6R) 400mg IV and then rituximab 1g IV repeated at eight weeks. He was continued on high dose oral prednisone, with a slow taper. He demonstrated first signs of return of lower limb power two week after induction immunosuppression, with return of 4/5 power in bilateral lower limbs at eight weeks with gradual return of assisted mobility at six months.
Conclusion Aggressive treatment of NMOSD should be considered in patients of advanced age even with delayed presentation, given the potential for a favourable clinical response.
