Acute brachial plexus neuropathy with involvement of cranial nerves IX, X, XI and XII

Acute brachial plexus neuropathy is characterized by acute onset of shoulder girdle and arm pain, followed by weakness of the shoulder and arm muscles. It affects primarily nerves of the upper trunk of the brachial plexus and the long thoracic nerve. Cranial nerve involvement is an infrequent association and implies a diagnostic challenge. We report a unique case of acute brachial plexus neuropathy with involvement of the cranial nerves IX, X, XI and XII.

Fifty six year-old woman who developed acute dysphonia, dysphagia and left shoulder pain, followed, six days later, by left arm weakness. Needle examination showed only fibrillation potentials and positive sharp waves in the left deltoid muscle. MRI of the brachial plexus shows enlargement of the trunks, cords and terminal branches, with mild gadolinium enhancement.

This case illustrates the unique presentation of neuralgic amyotrophy with involvement of nerves outside the brachial plexus, and the importance of MRI for diagnosis, in the absence of electrophysiologic involvement.