Validity of carpal tunnel syndrome diagnostic tests in diabetic patients

  Background: Carpal tunnel syndrome (CTS) is the most common compressive neuropathy. Although unprincipled and incorrect use of hands and non compliance with safety issues are underlying factors of CTS, but studies have shown that diabetes can predispose patients to CTS .   Objective: The aim of this study was to determine the sensitivity and specificity of diagnostic maneuvers of carpal tunnel syndrome in diabetic patients and to compare with non diabetic patients.   Methods: This cross-sectional study was conducted on 115 hands that were selected by census method in Milad hospital, Tehran during 2012. Demographic data were collected by a questionnaire and physical examination was performed for patients. The patients were divided into six groups based on electrodiagnosis response: normal, paresthesia without CTS , CTS, symptomatic diabetes without CTS, diabetes & CTS, diabetes & CTS & peripheral neuropathy. The sensitivity and specificity of Tinel's Sign, Phalen's Test, reverse Phalen's Test , Tourniquet Test, difference between two sharp points, Compression Test, and Flick Signal were determined in diabetic and nondiabetic patients. Data were analyzed by Chi-square test.   Findings: The mean age of the patients was 55 ± 13.25 and the mean duration of symptoms was 19 months. The prevalence of moderate CTS was higher than mild and severe CTS. Of 115 studied hands, there were 25 hands with CTS, 20 hands with diabetes & CTS hands, 23 hands with diabetes & CTS & peripheral neuropathy hands, 14 hands with paresthesia without CTS, 19 hands with symptomatic diabetes without CTS and 14 normal hands. In non-diabetic with CTS group, the Flick Signal and the reverse Phalen's test were the most sensitive tests , respectively while the Tinel's sign and the Phalen's test were the most specific tests (95%) . In diabetic group with CTS, reverse Phalen's test was the most sensitive test (56%) and the Tinel's sign was the most specific test (77%). In diabetic group with peripheral neuropathy & CTS , the Phalen's test and Compression test were the most sensitive tests (59%), and the Tinel's sign was the most specific test (77%). Overall the Compression test was the most sensitive test (51%) and the Tinel's sign was the most specific test (77%) in the diabetic group .   Conclusion: With regards to the results, using the Phalen's test , the reverse Phalen's test and the compression test in diabetic patients with CTS is suggested.