New therapeutic perspectives for demyelinating retrobulbar optic neuritis

In patients with demyelinating retrobulbar optic neuritis (RON), a spontaneous or corticosteroid-induced improvement is generally observed within the first month, but this is clinically insignificant in 5%-7% of patients. We report the case histories of four patients who were considered to be "non-responders" to corticosteroids because their visus remained unchanged or had improved by only 1/10 after one month from intravenous corticoid therapy begun 2-7 days after disease onset, and who were therefore subsequently administered high intravenous doses of immunoglobulin. Three of these patients completely recovered in a period of 3-9 months; the fourth showed only a partial improvement, but this was consolidated after long-term continuation of the same therapy. These cases suggest the possible efficacy of early administration of intravenous immunoglobulin in RON patients who fail to respond to cortisone therapy. As recently demonstrated in animal models, it can be hypothesised that the result is due to immuno-mediated mechanisms of action that reduce autoimmune responses in the short- and medium-term, and in the long-term favour remyelination.