Diagnosing neuromyelitis optica.

Neuromyelitis optica (NMO) is a severe inflammatory demyelinating disorder typically characterized by attacks of recurrent optic neuritis and transverse myelitis. Advances in magnetic resonance imaging techniques and the discovery of the relatively specific NMO IgG biomarker have led to improved diagnostic accuracy and greater recognition of the broad clinical spectrum of aquaporin 4-related autoimmunity. Brain lesions in NMO typically follow the distribution of aquaporin 4 expression and may be symptomatic. Prompt diagnosis of NMO and NMO spectrum disorders has important therapeutic implications given the high risk of recurrent attacks and consequent severe disability, especially in childhood-onset disease.