Clinical Findings of Asymptomatic Carpal Tunnel Syndrome in Patients With Diabetes Mellitus

OBJECTIVE: To evaluate the clinical differences between patients with diabetes mellitus (DM) who have asymptomatic carpal tunnel syndrome (CTS) and those who have symptomatic CTS. METHODS: Sixty-three patients with DM were assessed using the Boston Carpal Tunnel Questionnaire (BCTQ), nerve conduction studies (NCS), and ultrasonographic evaluation of the cross-sectional area (CSA) of the median nerve. According to the BCTQ responses and NCS results, the patients were divided into the following three groups: group 1 (n=16), in which NCS results did not reveal CTS; group 2 (n=19), in which NCS results revealed CTS but the group scored 0 points on the BCTQ (asymptomatic); and group 3 (n=28), in which NCS results revealed CTS and the group scored >1 point on the BCTQ (symptomatic). The clinical findings, NCS results, and CSA of the median nerve were compared among the three groups. RESULTS: There were no significant differences in age, DM duration, glycated hemoglobin levels, and presence of diabetic polyneuropathy among the three groups. The peak latency of the median sensory nerve action potential was significantly shorter in group 1 than in groups 2 and 3 (p<0.001); however, no difference was observed between groups 2 and 3. CSA of the median nerve at the carpal tunnel in group 2 was significantly larger than that in group 1 and smaller than that in group 3 (p<0.05). CONCLUSION: The results of our study suggest that the symptoms of CTS in patients with diabetes are related to CSA of the median nerve, which is consistent with swelling of the nerve.