Shoulder Weakness in a Sousaphone Player

Abstract

0404 HISTORY: A previously healthy 14-year-old sousaphone player presented with a 2-week history of progressive left arm weakness. He denied any preceding trauma. Review of systems was negative for pain, fever, weight loss, rash, or recent illness. He was right-hand dominant but supported the sousaphone on his left shoulder. He denied medications and his past medical history was negative. PHYSICAL EXAMINATION: Examination revealed a nondysmorphic male. His cervical spine showed full range of motion and was nontender. Spurling's test was negative. He showed increased scapular glide and winging on the left. Passive range of motion was full throughout. Active forward flexion and abduction of the left shoulder was limited to 90 degrees secondary to weakness. Strength in the left arm was 3+-4/5 including shoulder abduction, shoulder internal and external rotation, scapular plane elevation, elbow extension, wrist extension, forearm supination, thumb extension, and finger adduction and abduction. Elbow flexion, wrist flexion, thumb opposition and was 5/5 on the left. Sensation was decreased at the left lateral shoulder. Range of motion was full, strength was 5/5, and sensation was grossly intact in the right upper extremity. Deep tendon reflexes were 2+ and symmetric throughout. Strength, range of motion, and sensation was normal in the lower extremities. DIFFERENTIAL DIAGNOSIS: Brachial plexus traction/pressure injury Spinoglenoid cyst Posterior spinal column lesion Viral radiculitis-plexitis Infarction due to vasculopathy (Diabetes mellitus Parsonage-Turner Syndrome TEST AND RESULTS: C-spine AP, lateral, and lateral flexion/extension radiographs Normal, no bony abnormality, fracture, or subluxation Left shoulder radiographs Normal, no bony abnormality, dislocation, or fracture Left shoulder MRI Normal, no soft tissue mass or cyst Upper extremity EMG and nerve conduction study Denervation along the radial and axillary nerves; involving the deltoid, triceps, and extensor carpi radialis No evidence of radiculopathy, central process, or peripheral neuropathy Cervical spine MRI Normal, no evidence of a posterior cord lesion Left brachial plexus MRI Normal, no evidence of atrophy or lesion FINAL WORKING DIAGNOSIS: Parsonage-Turner Syndrome vs. Marching Band Compression Neuropathy TREATMENT AND OUTCOMES: The patient was asked to stop playing the sousaphone to avoid further compression of the brachial plexus and shoulder. He was placed in physical therapy to maintain strength and range of motion. The natural history and expected outcomes of possibe Parsonage-Turner Syndrome were discussed with the patient. He continues to be followed.