Brachial neuritis caused by varicella-zoster diagnosed by changes in brachial plexus on MRI.

Brachial neuritis is a rare disorder affecting the brachial plexus. It is characterized by the acute onset of shoulder and arm pain followed by weakness, sensory loss and atrophy. Diagnosis is essentially clinical with electrophysiological investigations and imaging useful in excluding other differentials and supporting the diagnosis. Magnetic resonance imaging (MRI) usually does not show any pathology in the brachial plexus or spinal cord. We present a case of a patient who had brachial neuritis preceded by varicella zoster infection. This was supported by MRI which showed abnormal signal consistent with inflammatory changes in the brachial plexus.