[Devic's optic neuromyelitis. 4 cases].
We report 4 cases of neuromyelitis optic (Devic's disease), with 3 to 7 year-follow-up for 3 of them. Most of the data agreed with the previously reported cases: subacute onset, association of optic neuritis and myelitis within several weeks or months, absence of relapse, good prognosis for paraplegia but poor prognosis for visual loss, and effectiveness of corticosteroids on spinal cord involvement in 4 cases. Moreover these 4 cases have revealed the following rare features: unilateral visual disturbance (1 case), total recovery of visual signs (1 case) with only a short period of follow-up, onset during childhood (1 case), onset following an acute lymphocytic meningitis (1 case), and dependency from corticosteroid therapy (2 cases). None of the patients had obvious immunological disturbance. N.M.R. imaging revealed in 2 cases, disseminated demyelinated areas which confirmed neuropathological data from the literature, showing that anatomical lesions could be wider than expected on clinical signs. The poor visual prognosis, the serum inflammatory signs, the epidemiologic data, the high cell and protein levels in C.S.F., and the absence of relapse suggested, in our cases and in most of the previously reported ones, that neuromyelitis optic must be differentiated from multiple sclerosis.