Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica (NMO) is an autoimmune disease that is characterized by antibody-mediated inflammation, demyelination, neuronal loss, and necrosis of the central nervous system (CNS) – most commonly of optic nerves, spinal cord, and brainstem. In 2006, Wingerchuk et al. proposed that the diagnosis of NMO requires a clinical episode of either optic neuritis (ON) or acute myelitis and at least two out of the three following supportive criteria for the diagnosis of NMO: continuous spinal cord lesion encompassing more than three vertebral segments on magnetic resonance imaging (MRI), brain MRI not fulfilling diagnostic criteria for multiple sclerosis (MS), and aquaporin-4 (AQP4) immunoglobulin G seropositivity. In 2015, the diagnostic criteria were once again revised to incorporate other characteristic findings of the disorder including an area postrema syndrome, tumefactive presentations, as well as brainstem, thalamic, and hypothalamic manifestations.