Postprocedural Brachial Neuritis: Clinical, Electrodiagnostic, and Neuroimaging Features

BACKGROUND AND PURPOSE: Brachial neuritis is a monophasic condition affecting the brachial plexus and its branches, manifesting as acute shoulder and upper arm pain, followed by weakness and paresthesias. It can be triggered by antecedent events, including procedures such as surgery. Misdiagnosis and delay in diagnosis are common. Imaging is important to confirm the diagnosis of postprocedural brachial neuritis and exclude other etiologies.

MATERIALS AND METHODS: Clinical, electrodiagnostic, and neuroimaging features of patients with postprocedural brachial neuritis from a single quaternary care institution were identified and analyzed.

RESULTS: Six patients (2 women) were identified with a median age of 62 (range 49–70) years. Antecedent procedures included 4 cervical spine surgeries, 1 rotator cuff repair, and 1 central venous catheter placement. Time to symptom onset ranged from 1 day to 2 weeks. The initial symptom for 5 of the 6 patients was severe upper extremity pain followed by weakness. All patients had electrodiagnostic tests and MR neurography consistent with brachial neuritis. MR neurogram showed plexus and/or terminal branch abnormalities with associated muscular denervation edema. The C5 or C6 root and/or upper trunk were always involved. The most common branches affected were the suprascapular, long thoracic, and axillary nerves. Hourglass constrictions (HGCs) of these nerves were seen in 3 of 6 patients. The average time to diagnosis was 3.4 (range 1.5–5) months.

CONCLUSIONS: Postprocedural brachial neuritis is an under-recognized cause of acute upper extremity pain and weakness. MR neurography can exclude iatrogenic causes and document the presence of HGCs in affected nerves. Diagnostic neuroradiologists should be aware of this clinical entity and associated neuroimaging findings.