1426 - Multifocal median neuropathy due to carpal tunnel syndrome and fascial band nerve compression in the forearm: a case study

Case Diagnosis: 71 year-old man with multifocal median neuropathy due to nerve compression within the carpal tunnel and also in the forearm due to entrapment from a fascial band

Case Description: The patient presented with right hand paresthesias and pain for one month. Physical exam showed mid-forearm tenderness, positive Tinel’s sign at the right wrist, positive carpal compression test, and decreased light touch sensation in a median nerve distribution. One month later, symptoms had worsened and were originating from halfway along the volar forearm and radiating into the fingers. The point of maximum positive Tinel’s was now 8 centimeters proximal to the transverse wrist crease. Electrodiagnostics suggested a demyelinating sensorimotor median neuropathy across the wrist and sensorimotor axonal loss and conduction block 7-8 centimeters proximally from the wrist base. At this forearm location, diagnostic ultrasound showed a fibrous band coursing radial to ulnar superficially over the median nerve terminating at the flexor digitorum superficialis tendon.

Discussions: Given persistent symptoms, the patient underwent surgery, during which the median nerve was confirmed to be compressed in the carpal tunnel. 8 centimeters proximal to the wrist crease, a fascial band was confirmed to compress the median nerve at the area of maximum positive Tinel’s sign. Two weeks after carpal tunnel release and fascial band transection, the patient’s pain had resolved, and physical exam confirmed symmetric sensation in the median and ulnar distributions.

This case showcases a rare presentation of median neuropathy at both the forearm and the wrist. This case underscores the benefits of combining different diagnostic modalities when investigating less common compressive median neuropathies.

Conclusions: It is important to maintain a broad differential diagnosis when investigating multifocal median neuropathy. Diagnostic ultrasound can be used to scan structures both in the wrist and forearm to evaluate the neuropathy, especially given the speed and relative low cost of ultrasonography.