Evaluation of the neurological involvement and prevalence of the carpal tunnel syndrome in patients with type-2 diabetes mellitus

Objective: to determine the frequency of the carpal tunnel syndrome (CTS) in patients with type 2 diabetes mellitus, verify whether it is associated with diabetic neuropathy (DN) and identify ways to recognize both by examining the upper limbs. Methods: The patients were submitted to anamnesis; the complaints were verified, tactile and vibratory sensitivity was evaluated, sensitive and motor nerve conduction (SMNC) was studied and Phalen’s test (PHT) was performed. The criteria for isolated CTS diagnosis were: alterations in the SMNC, complaints of paresthesia in the median nerve area and absence of either sensitive or motor alterations in the area of the ulnar nerve and lower extremities. Results: Of the 94 patients studied, 60 presented paresthesia. The SMNC study detected alterations in 88 patients (93.6%) and it was the most sensitive test. At the test to discriminate the two most static points (D2SP) we observed alterations in 47 patients and with the Semmes-Weinstein test detected alterations in 11 patients. Alterations were detected in 72 patients (76.6%) using the bioesthesiometer and in 04 patients using the diapason. PHT was positive in 33 patients. The correlation of the results showed that neural alterations were present in 92/94 patients; 11 patients presented alterations only in the median nerve and 81 patients presented combined alterations in the ulnar and median nerves. Only 4 patients presented CTS without subjacent neuropathy. Conclusions: The most sensitive tools were the bioesthesiometer and the D2SP. The neurophysiological examination demonstrated the presence of neuropathy subjacent to CTS. Clinical and neurophysiological criteria for CTS were presented by 31.91% of the patients; 27.66% with signs of subjacent neuropathy and 4.25% without diabetic neuropathy. Clinical criteria should be preponderant over the remaining tests and the neurophysiological test in order to characterize the carpal tunnel syndrome in the diabetic patient.