Optic neuritis: studies on the cerebrospinal fluid in relation to clinical course in 61 patients.

A prospective study on 61 previously healthy patients with acute mono-symptomatic optic neuritis is reported. Interest was focused on changes in the cerebrospinal fluid and the clinical course with possible development of multiple sclerosis. At the beginning of the disease, a mononuclear pleocytosis was noted in 51 per cent of the patients, an elevated IgG level in 18 per cent, and an oligoclonal IgG distribution in 41 per cent. These results are in sharp contrast to those in multiple sclerosis. Eleven patients have so far developed definite multiple sclerosis. At onset only five of these had cerebrospinal fluid findings indistinguishable from those in multiple sclerosis, with pleocytosis and bands on electrophoresis. In five more patients, who subsequently developed multiple sclerosis, the cerebrospinal fluid IgG was normal at onset, but an oligoclonal IgG appeared during the follow-up; there was no correlation in time between the appearance of new symptoms and cerebrospinal fluid changes. In six patients with normal cerebrospinal fluid and four patients with only mononuclear pleocytosis at the onset of disease, the IgG pattern became oligoclonal on electrophoresis during the follow-up period, although the patients had no further symptoms or signs of disease. It was concluded, therefore, that the cerebrospinal fluid was often normal in the first attack of what later proved to be multiple sclerosis, and that a normal fluid did not preclude a development into definite multiple sclerosis. Sometimes IgG bands appeared in previously normal cerebrospinal fluid, although the patients had not experienced new symptoms.