Carpal tunnel syndrome in leprosy patients’ household contacts: How should we interpret this condition?

Objectives

This study aimed to describe the prevalence of carpal tunnel syndrome (CTS) in leprosy household contacts, as well as its morphological and electroneuromyographical patterns.

Materials and methods

A prospective, cross-sectional study in which 28 HHCs were recruited with symptoms of carpal tunnel syndrome (CTS), who underwent ultrasonography (US) and electroneuromyography (ENMG). In the US, the cross-sectional area (CSA) of the median nerve was measured at the carpal tunnel (Mt) and 4 centimetres proximally to it (Mpt). In the ENMG, motor and sensory conduction studies were performed, assessing conduction velocities (CV), distal motor latencies (DML), amplitudes of sensory nerve action potentials (SNAP), and compound muscle action potentials (CMAP).

Results and discussion

The HHCs with CTS had a mean age of 52.7 (35.4) years, with a predominance of females (78.6%; 22/28). Bilateral involvement was observed in 67.8% (19/28) and unilateral in 32.2% (9/28), totalling 47 nerves evaluated. In the sensory conduction study by ENMG, 100% (47/47) showed reduced conduction velocity (CV), and 19.1% (9/47) showed reduced SNAP amplitude, with no evidence of asymmetry between the different sensory branches evaluated. In the motor conduction study by ENMG, 34.0% (16/47) showed prolonged distal motor latency (DML), 6.1% (3/47) had reduced CV, and no HHC showed reduced CMAP amplitudes. On US, 36.2% (17/47) showed increased CSA at the carpal tunnel (Mt), and none at the proximal segment (Mpt). None of the 28 subjects had any skin signs suggesting leprosy; 12 of them did, however, show other evidence of pure neural leprosy and were treated as such. The evidence suggested that the carpal tunnel syndrome in these cases was unrelated to the underlying leprosy infection.

Conclusion

Even though CTS has been described as a possible presentation of leprosy neuropathy in an at-risk population, CTS alone does not by itself indicate the presence of leprosy neuropathy.