Quantitative Epidermal Nerve Fiber Density Is More Sensitive Than Sudomotor Test To Detect Neuropathy in Type 2 Diabetes (P03.200)

Abstract

Objective: The aim of this study is to find sensitive method detecting early diabetic neuropathy and to evaluate relationship between somatic and sudomotor small nerve fiber function in diabetic neuropathy. Background It is known that small nerve fiber is involved first in diabetic neuropathy. Quantitative epidermal nerve fiber density and sudotmor function test are well known method to detect dysfunction of small nerve fiber. Design/Methods: Type 2 diabetic patients with putative neuropathy based on clinical symptoms or signs were included prospectively. Neurological examinations using neuropathy impairment score (NIS) and NCS were conducted. Quantification of intraepidermal nerve fiber (IENF) density and quantitative sudomotor axon reflex test using Q-sweat were done on the distal leg. Heart rate variability according to deep breathing (DB ratio) and Valsalva ratio were done to examine cardiovagal function. The results of the tests were compared between the patients with normal nerve conduction (small fiber neuropathy group, SFN) and abnormal nerve conduction (mixed fiber neuropathy group, MFN). Results: IENF density abnormality was most frequently detected, and Q-sweat, NCS, and cardiovagal function abnormalities were followed in order. Abnormality of the IENF density was found more frequently than that of Q-sweat and cardiovagal function in both SFN group and MFN group. Cardiovagal dysfunction, especially DB ratio, and NCS abnormality were significantly correlated with duration of the diabetes mellitus. There was no correlation between IENF density and Q-sweat performed on the same site. Conclusions: Quantitation of IENF density is more sensitive than Q-sweat to detect early diabetic neuropathy. Analyses of IENF density and Q-sweat are complementary for early detection of neuropathy in type 2 diabetes. Cardiovagal dysfunction and NCS abnormality are proportional to duration of the diabetes mellitus, so that regular follow-up of these tests are mandatory regardless of clinical symptoms. Disclosure: Dr. Sohn has nothing to disclose. Dr. Song has nothing to disclose. Dr. Lee has nothing to disclose.