Two patients with neuromyelitis optica but contrasting clinical courses

Neuromyelitis optica (NMO) is an idiopathic, relapsing, demyelinating disease of the central nervous system that preferentially affects the optic nerve and spinal cord. Diagnostic criteria for definite NMO require optic neuritis, myelitis, and at least two of three supportive criteria: onset brain MRI non-diagnostic of MS; spinal cord lesion extending over 3 or more vertebral segments; or seropositive for NMO-IgG. We report two Sri Lankan patients who fulfil the above diagnostic criteria but have contrasting clinical courses over a 4-year follow-up period. The NMOIgG seropositive patient demonstrated a more severe, relapsing disease course whilst the seronegative patient did not relapse despite not being on long-term immunosuppressive therapy. Given that para-infectious NMO is often monophasic and seronegative, discerning guidelines in recommending maintenance immunosuppression in NMO is required particularly in settings where incriminatory infections are prevalent.