Pathogenesis, diagnosis and treatment of neuromyelitis optica: Changing concept of an old disease

Abstract

The concept of neuromyelitis optica (NMO) has changed considerably during the past few years. The identification of autoantibodies in the sera generated against the water channel aquaporin 4 (AQP4) has increased the specificity of diagnosis and modified guidelines. A pathogenic role of anti-AQP4 antibodies has recently been indicated; they evoke the pathological and clinical hallmarks of the disease on transfer and cause necrosis of astrocytes expressing AQP4. The diagnosis of NMO is based on clinical, neuroimaging and serological criteria. Early therapy preventing relapses is mandatory, because neurological impairment accumulated during relapses is the main cause of permanent disability. In a number of cases defined as NMO spectrum diseases, the clinical manifestation is spatially limited. Such events of separate myelitis or relapsing/bilateral optic neuritis challenge diagnosis and might delay proper therapy. Here, current concepts of diagnosis and treatment of NMO and NMO spectrum diseases are summarized. Diagnostic and treatment decisions in different clinical situations are shown by discussion of cases. © 2010 Japanese Society for Neuroimmunology.