The brachial plexus neuropathy is a well-defined clinical entity that starts with sudden severe pain in the shoulder girdle followed in a few days or weeks by paralysis of the muscles over the affected shoulder. The prognosis is excellent for the return to a good function.

A case of brachial plexus neuropathy considered to be due to viral infection is described. The diagnosis was based on history of previous upper respiratory infection; symptoms and signs with fever, lymphocytosis without leukocytosis and electrodiangnostic findings.