AANEM Connect

Case Presentation:
I am presenting the case of a 44-year-old male who sustained an anterior shoulder luxation while playing football. After reduction by an orthopedist, he developed noticeable deficits in shoulder and arm strength, as well as paresthesias in the hand.

Clinical Findings:

• Motor Deficits: Weakness in arm flexion, shoulder abduction, wrist extension, abductor pollicis brevis (APB), and abductor digiti minimi (ADM).
• Sensory Deficits: Diminished sensation in the distribution of the radial, third digit, and fifth digit nerves.

NCS Findings:

• Slightly reduced amplitude in APB.
• Markedly reduced amplitude in ADM.
• Reduced sensory responses in digit 3, radial nerve, and digit 5—more pronounced in radial and digit 5.

EMG Findings (15 Days Post-Injury):
This is where I encountered a puzzling observation:

• Muscles Examined: Deltoid, biceps, wrist extensors, APB, first dorsal interosseous (FDI), long supinator, and ADM.
• Findings: No fibrillations or spontaneous activity were observed.
• Recruitment Activity: Absent in all muscles except the biceps, where limited activity was present.

Given the deficits and the NCS findings, I initially suspected a brachial plexopathy, likely affecting the upper trunk. However, the absence of fibrillations 15 days post-injury raises questions, as one would typically expect early signs of denervation by this time.     

My Questions:

1. Is the absence of fibrillations at this stage consistent with a plexopathy, or should I consider an alternative explanation?
2. Could the lack of EMG activity be attributed to technical factors or perhaps a central nervous system contribution?
3. Would you recommend any additional studies (e.g., imaging, repeat EMG at a later time) to clarify the diagnosis?

I appreciate any insights or similar experiences the community can share, as I aim to better understand the underlying mechanisms in this case.

Thank you