The clinical course of neuromyelitis optica (Devic's syndrome)

Objectives: To evaluate the spectrum of neuromyelitis optica (NMO), includi ng characteristics of the index events (optic neuritis [ON]) and myelitis), neuroimaging, CSF, and serologic studies, and to evaluate the long-term co urse. Methods: Review of 71 patients with NMO evaluated at the Mayo Clinic between 1950 and 1997. Results. NMO was either monophasic or relapsing. Pat ients with a monophasic course (n = 23) usually presented with rapidly sequ ential index events (median 5 days) with moderate recovery. Most with a rel apsing course (n = 48) had an extended interval between index events (media n 166 days) followed within 3 years by clusters of severe relapses isolated to the optic nerves and spinal cord. Most relapsing patients developed sev ere disability in a stepwise manner, and one-third died because of respirat ory failure. Features of NMO distinct from "typical" MS included >50 cells/ mm(3) in CSF (often polymorphonuclear), normal initial brain MRI, and lesio ns extending over three or more vertebral segments on spinal cord MRI. Conc lusions: Clinical, laboratory, and imaging features generally distinguish n euromyelitis optica from MS. Patients with relapsing optic neuritis and mye litis may have neuromyelitis optica rather than MS. Patients with a relapsi ng course of neuromyelitis optica have a poor prognosis and frequently deve lop respiratory failure during attacks of cervical myelitis.