The Study Of Diabetic Thermal Sensory Neuropathy

Objective To study the diabetic thermal sensory neuropathy and investigate the significance of quantitative thermal testing (QTT) in diagnosis of the early diabetic peripheral neuropathy.Methods The 169 diabetic patients (83 males, 86 females) with neurological deficit and the 53 age-matched healthy controls (24 males, 29 females) were determined cold threshold (CT),warm threshold (WT), cold pain threshold (CPT), warm pain threshold (WPT) in both dorsum of the hands and dorsum of the feet. The 169 diabetic patients were determined nerve conduction study (NCS). These results were analyzed in statistic method.Results The cold and warm threshold in both the dorsum of the hand and dorsum of the feet of the patients(course of disease≤5 years) were higher than that of the healthy controls. The difference was significan(t P< 0.05). The thermal thresholds of the patients(course of disease> 5 years)were higher than that of the patients(course of disease≤5 years). There was a significant difference ( P< 0.05). The thermal thresholds of the patients with normal NCS were higher than that of the healthy controls. The difference was significant(P<0.05). The frequency of abnormality of the NCS in all patients was 73.37%, and that of QTT was 89.94%. The frequency of abnormality of the QTT was higher than that of the NCS(P< 0.05) . There was a significant difference(P< 0.05) . The frequency of abnormality of QTT and NCS of the patients with course of disease more than 5 years course were higher than that of the patients with course of disease no more than 5 years( P< 0.05) . There was no significant difference in the abnormality frequency of QTT in patients with normal NCS and in patients with abnormal NCS. The abnormality frequency of WT( 86.39%)was higher than that of CT( 68.05%)( P< 0.05). The abnormality frequency of QTT in dorsum of the feet( 86.39%) was higher than that in the hand(s 53.85%)( P< 0.05). The pain thresholds of diabetic patients were higher than that of the healthy controls and the difference was significant( P< 0.05). 95% range of values of diabetic patients overlap 95% range of values of healthy controls widely.Conclusion( 1) The diabetic thermal sensory neuropathy relates to the course of disease. The longer the course of disease is, the more severe the thermal sensory neuropathy is. ( 2) The small diameter fibers of diabetic patients are more vulnerable to damage than the large diameter fibers. ( 3)The thermal sensory neuropathy is length dependent. ( 4) Unmyelinated C small fibers are more vulnerable than myelinated Aδsmall fibers. ( 5) QTT is an useful test in the diagnosis of diabetic neuropathy. ( 6) WT is a sensitive test parameter in the diagnosis of diabetic neuropathy. ( 7) Pain threshold testing is not sensitive and specific in diagnosis of diabetic neuropathy. The value of the pain threshold needs follow-up in the advanced study.