ELECTROPHYSIOLOGICAL FINDINGS IN DIABETIC PATIENTS WITH CLINICAL DIAGNOSIS OF CARPAL TUNNEL SYNDROME

Objective: The aim of this study was to evaluate the frequencies of carpal tunnel syndrome (CTS) and polyneuropathy (PNP) in type 2 diabetic patients referred to the electrophysiology section with the clinical diagnosis of CTS. Materials and Methods: Patients with type 2 diabetes, referred to our electrophysiology section with clinical CTS with a minimum of three of the four complaints of numbness, burning paresthesias, pain, and clumsiness in one or both hands, were included in this study. Patients with subjective complaints and/or objective findings of other involvement than median nerve in neurological examination were excluded. Conventional nerve conduction studies and needle electromyography were performed. Patients were diagnosed as having CTS or polyneuropathy (PNP) according to the electrophysiological examinations. Median nerve involvement was classified as mild or severe. Fisher exact test and student's t-test was used for statistical evaluation. Results: Of the total 56 patients, 2 had normal electrophysiological examinations and 3 had normal median nerve conduction studies. Electrophysiological examinations revealed CTS in 33 and PNP in 18 patients. CTS were detected bilaterally in 21 and unilaterally in 12 patients. Bilateral involvement, the severity of the median nerve involvement and the latencies and sensory action potential amplitudes of median nerve sensory conduction studies and 3the distal latencies, motor conduction velocities and compound muscle action potential amplitudes in median nerve motor conduction studies did not differ significantly. Conclusion: Diabetic polyneuropathy can present with clinical signs of CTS, because peripheral nerves become vulnerable due to the metabolic alterations during diabetes and can initially be affected at the entrapment sides due to the mechanical effects. Median nerve conduction studies did not significantly differ in CTS and PNP in this study. The clinical diagnosis of both CTS and PNP should be mentioned when requesting electrophysiological examination, even if the clinical signs indicate CTS.