Shock Wave Injury to the Brachial Plexus: The Critical Role of Early EMG in Diagnosis and Recovery

Case Diagnosis: Upper trunk brachial plexopathy secondary to shockwave injury from a gunshot wound.

Case Description or Program Description: A 38-year-old male sustained a gunshot wound to the left jaw with a retained bullet in the right deltoid, resulting in a right scapular fracture, hyoid bone fracture, and left mandibular fracture. He developed severe right upper extremity (RUE) weakness, numbness, hyperesthesia, and muscle atrophy. Given his scapular fracture, initial weakness was attributed to pain-related disuse. EMG at three months post-injury revealed upper trunk brachial plexopathy, likely due to shock wave injury. He saw pain management for severe neuropathic pain but had not started physical or occupational therapy (PT/OT). At ten months post-injury, repeat EMG showed active reinnervation. PT/OT and neuromuscular electrical stimulation (NMES) were initiated, leading to mild strength gains and improved range of motion (ROM).

Setting: Acute hospital followed by outpatient clinics and rehabilitation.

Assessment/Results: At three months post-injury, RUE strength was 1/5 for shoulder abduction, external rotation, and elbow flexion/extension, with 0º ROM in all planes. By ten months, after PT/OT and NMES, strength improved to 2/5 shoulder abduction and 3/5 elbow flexion/extension. ROM increased to 70º flexion, 60º abduction, and 30º external rotation.

Discussion (relevance): This case highlights the importance of early EMG in distinguishing true neurological injury from weakness due to pain and disuse, preventing misdiagnosis and unnecessary rehabilitation delays. Delayed intervention contributed to muscle atrophy and prolonged impairment. The likely mechanism of injury—a shock wave effect from the bullet—emphasizes recognizing indirect nerve trauma. Physiatrists play a critical role in recognizing brachial plexopathy, ensuring early diagnosis, initiating rehabilitation, and optimizing recovery to prevent long-term disability.

Conclusions: Physiatrists are essential in early recognition and management of brachial plexopathy. Timely EMG evaluation differentiates neurological injury from pain-related weakness, preventing rehabilitation delays. Early intervention with NMES, PT/OT, and comprehensive pain management maximizes recovery, minimizes long-term disability, and restores patient independence.