- This article focuses on the diagnosis and management of neuromyelitis optica spectrum disorder (NMOSD). NMOSD is an autoimmune, demyelinating condition characterized by inflammation of the optic nerve and/or the spinal cord, with symptoms that can range from mild impairment of movement to paralysis. The newly approved diagnostic criteria have improved the accuracy of NMOSD diagnosis. The management of NMOSD is under major revolution due to the many new therapeutic options. The role of the antibodies directed at aquaporin-4 (AQP4) has materialized as a biomarker for NMOSD. Several new treatments that target variable aspects in immunopathology such as IL-6, complement, or depletion of B cells are emerging. The management of AQP4-negative patients remains challenging.