Painless Neuralgic Amyotrophy (Parsonage-Turner Syndrome) – A Case Report

Abstract

Background: Neuralgic amyotrophy (NA) is a rare disorder typically characterized by an abrupt onset of upper extremity pain followed by progressive muscle weakness, atrophy and occasional sensory loss. Although NA has been hypothesized to be an autoimmune-mediated disorder. It is considered a primarily clinical diagnosis, electrodiagnostic evaluation is essential for the diagnosis confirmation and can exclude other etiologies. Electrodiagnostic findings can reveal patchy damage to any nerve within the brachial plexus. Case Description: In the current case report, we are presenting a 43-years-old man admitted to the Neurology Department of “UMHAT Dr. Georgi Stranski” in Pleven, Bulgaria, with decreased muscle strength and limited active movements in the left upper shoulder for approximately 3 weeks. The patient denied feeling any pain during the onset and afterwards. He had no previous infections, vaccinations and history of other diseases. The detailed neurological examination showed the left upper extremity decreased antigravity strength in the deltoid and infraspinatus muscles with marked atrophy of the same. Hyporeflexia of the left biceps and brachioradialis deep‐tendon reflexes was present. Electromyography findings showed denervation of the deltoid and infraspinatus muscles. Initial reinnervation of supraspinatus and cervical paraspinal muscles was present. The diagnosis of NA was confirmed by both the neurological examination and the electrophysiological findings. Conclusion: We are presenting a clinical case of idiopathic neuralgic amyotrophy with atypical painless presentation and discussing the most significant aspects of the disorder with regards to the difficulties in approaching the correct diagnosis. A better understanding of the NA clinical symptoms and signs variability improves the diagnostic and therapeutic approach.