366 - Unusual Manifestation of Parsonage Turner Syndrome: A Case Report

Friday, February 23, 2024

5:00 PM – 6:30 PM EDT

Presenting Author(s)

LW

Lili Wang, DO

Resident
Burke Rehabilitation Hospital
White Plains, New York, United States
Rohini Singh, DO

Resident Physician
Burke Rehabilitation Hospital
White Plains, New York, United States

Co-Author(s)

MO

Mooyeon Oh-Park, MD

Chief Medical Officer
Burke Rehabilitation
White Plains, New York, United States

Case Diagnosis: 58-year-old right handed male with a past medical history of type 2 diabetes mellitus, hypertension, and hyperlipidemia presented with a seven month duration of progressively worsening left shoulder and arm weakness.

Case Description: The classical form of Parsonage Turner Syndrome (PTS) presents with excruciating pain following an inciting event, with subsequent weakness or sensory changes in areas innervated by affected nerves. We present a patient that developed acute proximal left shoulder weakness after lifting heavy objects without any pain, sensation changes, numbness or tingling. The patient was noted to have atrophy involving the left posterior deltoid, periscapular muscles and biceps. He was unable to abduct shoulder past 30 degrees, initiate elbow flexion along with weak supination. MRI of the cervical spine showed degenerative changes and bilateral foraminal narrowing. MRI of the left shoulder was remarkable for chronic subdeltoid bursitis, small partial tear of bicep and supraspinatus tendons. Patient was evaluated by orthopedic and spine surgery and referred to PM&R to rule out PTS.

Discussions: In this case, electrodiagnostic testing revealed denervation of the C5 and C6 nerve roots, specifically involving the axillary and musculocutaneous nerves. This denervation affected the supraspinatus, infraspinatus, deltoid, and biceps muscles, which align with the upper trunk of the brachial plexus. Additionally, there was patchy involvement of the muscles in the left upper limb, characterized by denervation potentials. Some muscles were spared, while others were significantly impacted, all within the same nerve root innervation. These observations were inconsistent with cervical radiculopathy, leading to the consideration of Parsonage Turner Syndrome.

Conclusions: Parsonage Turner Syndrome presents with a wide spectrum of clinical symptoms, making it challenging to diagnose. Although it is considered a diagnosis of exclusion, a thorough physical examination, nerve conduction studies (NCS), and electromyography (EMG) can be helpful in confirming diagnosis.