Clinical, Electrophysiological Findings in Adult Patients with Non-traumatic Plexopathies

Abstract

Objective: To ascertain the etiology of non-traumatic plexopathy and clarify the clinical, electrophysiological characteristics according to its etiology.

Method: We performed a retrospective analysis of 63 non-traumatic plexopathy patients that had been diagnosed by nerve conduction studies (NCS) and needle electromyography (EMG). Clinical, electrophysiological, imaging findings were obtained from medical records.

Results: We identified 36 cases with brachial plexopathy (BP) and 27 cases with lumbosacral plexopathy (LSP). The causes of plexopathy were neoplastic (36.1%), thoracic outlet syndrome (TOS) (25.0%), radiation induced (16.7%), neuralgic amyotrophy (8.3%), perioperative (5.6%), unknown (8.3%) in BP, while neoplastic (59.3%), radiation induced (22.2%), neuralgic amyotrophy (7.4%), psoas muscle abscess (3.7%), and unknown (7.4%) in LSP. In neoplastic plexopathy, pain presented as the first symptom in most patients (82.8%), with the lower trunk of the brachial plexus predominantly involved. In radiation induced plexopathy (RIP), pain was a common initial symptom, but the proportion was smaller (50%), and predominant involvements of bilateral lumbosacral plexus and whole trunk of brachial or lumbosacral plexus were characteristic. Myokymic discharges were noted in 41.7% patients with RIP. Abnormal NCS finding in the medial antebrachial cutaneous nerve was the most sensitive to diagnose TOS. Neuralgic amyotrophy of the brachial plexus showed upper trunk involvement in all cases.

Conclusion: By integrating anatomic, pathophysiologic knowledge with detailed clinical assessment and the results of ancillary studies, physicians can make an accurate diagnosis and prognosis.

Keywords: Brachial plexus neuropathies; Electrophysiology; Lumbosacral plexus neuropathies; Neoplasm; Radiation.

Fig. 1

(A) PET-CT in a patient with malignant peripheral nerve sheath tumor (arrow) in right brachial plexus. Histopathologic confirmation was malignant transformation originating from neurofibroma. (B, C) Brachial plexus MRI and PETCT in a patient with chloroma. Brachial plexus MRI shows diffuse enhancement and swelling (arrow) in brachial plexus from trunk to cord level which suggests peri-plexus infiltration of chloroma.

Fig. 2

Brachial plexus MRI in a patient with radiation induced brachial plexopathy (A, B). Images show signal change and enhancement in brachial plexus [arrow, A], and fibrosis in subscapularis, teres minor, pectoralis, and infraclavicular soft tissue [arrow, B] which suggest radiation induced fibrosis. (C) Pelvis CT demonstrates osteosclerotic cystic lesions (arrow) in right ilium which suggest association with radiation. (D) Pelvis X ray shows dense radiopacity lesions (arrow) in both ilia which suggest osteonecrosis.