Upper Limb Weakness in a Triathlete

Abstract

HISTORY: A 36-year-old Ironman triathlete presented with 3 weeks of moderate burning neck pain and right upper limb weakness. He appreciated increasing weakness of right elbow extension, finger flexion, and shoulder motion. He described difficulty opening jars and performing a push up. He also described right upper limb tingling sensations into his hand. About 5 weeks prior to the onset of weakness he was treated with antibiotics for an upper respiratory infection and subsequently developed C. difficile colitis. He denied antecedent trauma. PHYSICAL EXAMINATION: The patient demonstrated winging of the right scapula, slight weakness of right shoulder external rotation, and weakness of the thumb and finger flexors. Strength and tone were normal in the left upper limb and bilateral lower limbs. Reflexes were present and symmetric. Sensation was diminished in the medial aspect of the right forearm. DIFFERENTIAL DIAGNOSIS: 1. Cervical Radiculopathy 2. Brachial Plexopathy 3. Peripheral Nerve Injury TEST AND RESULTS: Cervical spine MRI: No significant abnormalities Right upper limb EMG: No motor unit recruitment in the right serratus anterior and pronator quadratus. Decreased recruitment in the right infraspinatus. Decreased right median compound motor amplitude potential compared to the left side. Decreased right median, radial, and lateral antebrachial cutaneous sensory amplitude potential compared to the left side. FINAL/WORKING DIAGNOSIS: Acute Brachial Neuritis (Parsonage-Turner Syndrome) TREATMENT AND OUTCOMES: 1. Physical and occupational therapy for rotator cuff strengthening, scapular stabilization, and hand function. 2. Splinting of the right thumb for functional positioning. 3. Repeat EMG to assess degree of reinnervation is pending.