Brachial neuritis following infection with Epstein-Barr virus.

A 54-year-old woman developed stiffness across the shoulders and a mild headache during a motorcycle tour of the U.S.A. On return to the U.K. she complained of persisting exhaustion and painful muscles. Hospital admission was precipitated by her developing weakness in the right arm and paraesthesiae in the fingers. She was found to be suffering from infectious mononucleosis.