Brachial neuritis: an uncommon cause of shoulder pain.

Shoulder pain is one of the leading complaints of athletes seeking care from sports medicine physicians. Differential diagnosis includes a spectrum of orthopedic and nonorthopedic problems. In individuals who report acute atraumatic onset of shoulder pain followed by weakness, brachial neuritis should be considered. Brachial neuritis is an uncommon, idiopathic syndrome that typically affects the lower motor neurons of the brachial plexus. Involvement of a single nerve or nerve branches can also occur. Although symptomatology and physical examination findings may vary, the clinical course is generally characterized by acute onset of severe pain followed by weakness and gradual recovery.