ABSTRACT
Case Diagnosis: A 78-year-old man with Parsonage- Turner Syndrome (PTS). Case Description or Program Description: The patient developed acute left-sided neck and shoulder pain upon awakening five days after receiving a Moderna COVID-19 vaccine booster shot. Clinical examination, electrodiagnostic studies, and magnetic resonance imaging were consistent with a diagnosis of PTS. Setting(s): Tertiary referral center. Assessment/Results: His physical exam revealed severe weakness in left shoulder abduction and external rotation without sensory deficits. An urgent MRI of his cervical spine demonstrated multilevel degenerative changes including severe bilateral C5-6 neural foraminal narrowing, and an MRI of the left shoulder showed mild degenerative changes. He was treated with a sixday course of an oral methylprednisolone dose pack and his pain and weakness significantly improved. He was referred for electrodiagnostic testing 24 days after the onset of his symptoms, and by the time of the study, his pain and weakness had improved by 50%. The test revealed no significant abnormalities in the sensory and motor nerve conduction studies. Needle electromyography showed abnormal spontaneous activity in both the left infraspinatus and left deltoid with decreased recruitment of polyphasic motor unit action potentials in the left deltoid. Notably, the left mid/low cervical paraspinals, and other left C5/C6 innervated muscles including the biceps, and brachioradialis were all normal, making a diagnosis of cervical radiculopathy unlikely. Discussion (relevance): There have been eight published reports of PTS related to COVID-19 vaccinations at the time of this publication, which are also reviewed. Reports have occurred in three separate vaccines with variable onset of symptoms and recovery patterns as detailed in the table provided. Conclusion(s): Our case report and review of the literature highlights the importance of recognizing PTS as a potential cause of severe shoulder/arm pain and weakness after administration of a COVID-19 vaccine.