Neuromyelitis optica: a distinct demyelinating disease of the central nervous system

Abstract

We review and discuss the pathogenesis, epidemiology, diagnosis as well as recent advances in the treatment of NMO. We also highlight areas of future research. A review was carried out on reports drawn from MEDLINE until 2007. Neuromyelitis optica (NMO) is a relative uncommon demyelinating disease of the central nervous system (CNS) that preferentially affects the optic nerves and spinal cord. NMO follows an unpredictable course, being either monophasic or relapsing. The relapsing form of NMO primarily affects women with onset varying from childhood to adults in their 40s or elderly. Until recently, NMO was considered to be a variant of multiple sclerosis. However, in contrast to multiple sclerosis, NMO attacks are not mediated by T cells but rather by B cells and NMO-immunoglobulin G antibodies that target aquaporin-4. Humoral immune mechanisms, including complement activation plays an important role in the pathogenesis of NMO. At present, parenteral corticosteroids are widely employed as first-line treatment of optic neuritis and myelitis attacks, whereas therapeutic plasmapheresis is applied in the case of corticosteroids failure. Various strategies for the prevention of NMO relapses have been employed in small case series with modest activity. Recent advances in the clinical, neuroimaging, laboratory and pathological hallmarks have established that NMO is a distinct demyelinating disease of the CNS.