Neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorders, abbreviated NMOSD, are a spectrum of autoimmune diseases characterized by acute inflammation of the optic nerve, called optic neuritis, and of the spinal cord, called myelitis. Episodes of optic nerve and spinal cord inflammation may occur together or in succession, and the condition commonly follows a pattern of recurring attacks, particularly when untreated. Within the spectrum, neuromyelitis optica itself is a specific disease form marked by optic neuritis and extensive longitudinal spinal cord inflammation; more than eighty percent of neuromyelitis optica cases stem from immunoglobulin G autoantibodies targeting aquaporin 4, the predominant water channel protein in the central nervous system. The wider NMOSD spectrum also includes related conditions with presentations that vary from the standard form.