330 - Overlapping symptomatology of radial wrist pain - Superficial Radial Sensory Neuropathy

Case Diagnosis: Superficial Radial Sensory Neuropathy

Case Description: A 28-year-old mother of four young children presented to an electrodiagnostic clinic with five months of left radial wrist pain and paresthesias extending into the thumb and index finger, felt to be due to de Quervain’s tenosynovitis or carpal tunnel syndrome (CTS). Physical exam showed decreased sensation to light touch in the thumb and index finger and positive Finkelstein test. Electrodiagnostic study (EDx) revealed a superficial radial sensory neuropathy with a prolonged peak latency of 3.1 ms and normal amplitude. There was no evidence of median neuropathy, generalized peripheral neuropathy, or cervical radiculopathy. Needle study including the radially innervated triceps and extensor indicis proprius was normal.

Discussions: Our patient was revealed to have superficial radial neuropathy (SRN) through EDx. SRN, also known as cheiralgia paresthetica, or Wartenberg’s syndrome, is an uncommon neuropathy caused by the entrapment of the superficial radial nerve. It is an underrecognized etiology given its overlapping clinical manifestations with more prevalent conditions such as de Quervain’s or CTS. The superficial radial nerve courses underneath the brachioradialis and runs over the anatomic snuffbox to supply sensation to the dorsoradial surface of the hand and the first three digits. Understanding its nerve distribution is important as SRN can be mistaken for CTS. Differentiating between SRN and de Quervain’s can be challenging as they share a similar anatomical entity; the stuff box includes the first extensor compartment which, with stenosing inflammation, results in de Quervain’s. This case shows the value of a thorough physical exam and use of appropriate diagnostic tools to identify the underlying condition.

Conclusions: Given the overlapping symptomatology of radial wrist pain diagnoses, it is important for clinicians to be aware of clinical manifestations of, and consider electrodiagnostic study for, superficial radial neuropathy to accurately diagnose and manage the condition appropriately.