1602 - Triple Threat: A Unique Presentation of Dual Nerve Compression Syndromes with Associated Parsonage Turner Syndrome

Case Diagnosis: C6-C7 cervical radiculopathy, Parsonage-Turner syndrome affecting the posterior interosseous nerve, and ulnar neuropathy

Case Description: A 70-year-old male presented with burning left neck pain, upper extremity discomfort, and hand weakness. Examination revealed weakness in hand and forearm muscles. Initial cervical MRI showed C6-C7 spinal stenosis suggestive of possible cervical radiculopathy. A C7-T1 interlaminar corticosteroid injection was performed, relieving pain, but weakness persisted. Due to the complex nature and persistence of the patient’s weakness, a brachial plexus MRI was ordered, revealing lower plexus edema suggesting a diagnosis of Parsonage-Turner syndrome. EMG was then ordered and performed by a separate provider. The EMG conclusion suggested a C8-T1 radiculopathy, implying possible cervical spine surgery; however, the ordering physician’s review of EMG results and MRI data confirmed a C6-C7 radiculopathy, cubital tunnel syndrome, and Parsonage-Turner syndrome affecting the posterior interosseous nerve. Cubital tunnel release was performed and significantly improved strength, reasserting no need for cervical spine surgery.

Discussions:

Double crush syndrome, proposed by Upton and McComas in 1973, suggests proximal nerve lesions disrupt axoplasmic flow, predisposing distal nerves to injury, potentially due to inflammation or microvascular changes. This case illustrates a rare “triple threat” of concurrent nerve injuries, complicating diagnosis. Initial EMG misinterpretation as C8-T1 radiculopathy, despite no MRI abnormalities at that level, underscores the need for independent review of diagnostic findings.

Conclusions:

This rare combination of cervical radiculopathy, Parsonage-Turner syndrome, and cubital tunnel syndrome highlights the diagnostic complexity of multiple nerve injuries. This case is a strong example of why extensive neuroanatomical understanding is critical for accurate diagnosis in complex scenarios. Independent review of EMG and imaging is essential to prevent unnecessary procedures and expedient therapeutic interventions, as evidenced by the patient’s improvement post-cubital tunnel release.