Severe optic neuritis in infectious mononucleosis.

Because the presentation and clinical features of infectious mononucleosis can be misleading in the elderly, a significant number of infections may go unrecognized. We report an unusual case of infectious mononucleosis in a 61-year-old man in whom marked visual impairment was the presenting complaint and severe optic neuritis was the only prominent finding. Confirmation of the diagnosis was made by serologic testing for Epstein-Barr virus antibody. Recovery of visual function was near complete, but optic atrophy persisted. We reviewed the English literature and collected seven cases of well-documented optic neuritis associated with infectious mononucleosis. A clinical profile of parainfectious optic neuritis is discussed along with the likely pathogenesis for this complication.