1637 - Post-Gunshot Paresthesias Mimicking Median Nerve Mononeuropathy

Case Diagnosis: Paresthesias of the Left Upper Extremity After Gunshot Wound

Case Description: A 32-year-old male with a history of a gunshot wound to the left hand 2.5 years prior presented with forearm pain, paresthesias, and numbness radiating into the first three digits. Previous treatments included a carpal tunnel steroid injection with dexamethasone and xylocaine, as well as nighttime wrist bracing, without symptom relief. Musculoskeletal examination revealed weakness in forearm pronation (with the elbow flexed and extended), wrist extension, wrist flexion, finger abduction, finger flexion at distal and proximal interphalangeal joints, and thumb abduction, with preserved elbow flexion and extension. Additional findings included thenar eminence atrophy, a positive OK sign, and a positive Tinel’s sign at the left carpal tunnel. Electromyography and nerve conduction studies of the left upper limb were normal, with no evidence of median mononeuropathy at the left wrist or elbow, radiculopathy at the left C6-T1 root levels, other focal nerve entrapments, or polyneuropathy in the left upper limb.

Discussions: Reference values for this study were adjusted for age, gender, and BMI in accordance with AANEM Practice Guidelines (Chen et al., 2016). All nerve conduction studies were within normal limits. Prior studies have described patients with “carpal tunnel syndrome-like” symptoms having normal median and ulnar EMG/NCS. Such discordance between clinical presentation and objective electrodiagnostics highlights the potential for false negatives in standard testing. Adjunctive modalities, such as targeted ultrasound, may help identify small lesions responsible for these symptoms that are otherwise missed with routine electrodiagnostics. Our case extends these observations to post-gunshot paresthesias, for which no similar reports were identified.

Conclusions: Existing literature suggests that patients with gunshot injuries and median nerve symptoms typically demonstrate abnormal EMG/NCS findings. To our knowledge, this is the first reported case of post-gunshot paresthesias with normal electrodiagnostic studies.