Electrochemical skin conductance to detect sudomotor dysfunction, peripheral neuropathy and the risk of foot ulceration among Saudi patients with diabetes mellitus.

Eman Sheshah,Fahad Al-Greesheh,Mohammad Al-Harbi,Khaled Al-Madani,Reem Aman,Abdul Aziz Al-Ghamdi,Amal Madanat,Dalal Al-Qaisi

doi:10.1186/s40200-016-0252-8

Abstract

BackgroundSudomotor dysfunction is manifested clinically as abnormal sweating leading to dryness of feet skin and increased risk of foot ulceration. The aim of this study was to test the performance of foot electrochemical skin conductance (ESC) to detect diabetic peripheral neuropathy and the risk of foot ulceration against traditional methods in Saudi patients with diabetes mellitus.MethodsThis cross-sectional study was conducted on 296 Saudi patients with diabetes mellitus. Painful neuropathic symptoms were evaluated using the neuropathy symptom score (NSS). The risk of foot ulceration and diabetic peripheral neuropathy were determined using the neuropathy disability score (NDS). Vibration perception threshold (VPT) was assessed using neurothesiometer. Neurophysiological assessment of the right and left sural, peroneal and tibial nerves was performed in 222 participants. Diabetic peripheral neuropathy was defined according to the definition of the American Academy of Neurology. ESC was measured with Sudoscan.ResultsFeet-ESC decreased as the scores of sensory and motor function tests increased. Feet-ESC decreased as the NSS, NDS and severity of diabetic peripheral neuropathy increased. Sensitivity of feet-ESC < 50μS to detect diabetic peripheral neuropathy assessed by VPT ≥ 25 V, NDS ≥ 3, NDS ≥ 6 was 90.1, 61 and 63.8 % respectively and specificity 77, 85 and 81.9 % respectively. Sensitivity of feet-ESC < 70μS to detect diabetic peripheral neuropathy assessed by VPT ≥ 25 V, NDS ≥ 3, NDS ≥ 6 was 100, 80.6 and 80.9 % respectively. Sensitivity and specificity of feet-ESC < 70μS to detect confirmed-diabetic peripheral neuropathy were 67.5 and 58.9 % respectively.ConclusionSudoscan a simple and objective tool can be used to detect diabetic peripheral neuropathy and the risk of foot ulceration among patients with diabetes mellitus. Prospective studies to confirm our results are warranted.

Highlights

Sudomotor dysfunction is manifested clinically as abnormal sweating leading to dryness of feet skin and increased risk of foot ulceration
While peripheral artery disease accounts for an increased risk of foot ulceration (FU) in only 35 % of cases, diabetic peripheral neuropathy (DPN) contributes to 78 % of the risk of FU, and together with foot deformity and repetitive trauma forms the clinical triad that leads to FU [5, 6]
We demonstrated that in Saudi patients with diabetes mellitus (DM), severe sudomotor dysfunction (SMD) as defined by a feet-electrochemical skin conductance (ESC) threshold below 50 μS was sensitive and highly specific in detecting DPN assessed by Vibration perception threshold (VPT) and neuropathy disability score (NDS)

Summary

Introduction

Sudomotor dysfunction is manifested clinically as abnormal sweating leading to dryness of feet skin and increased risk of foot ulceration. The aim of this study was to test the performance of foot electrochemical skin conductance (ESC) to detect diabetic peripheral neuropathy and the risk of foot ulceration against traditional methods in Saudi patients with diabetes mellitus. In the context of diabetic peripheral neuropathy (DPN) sudomotor dysfunction (SMD) can occur in two phenotypes: either as one component of a generalized DPN, or concurrently in distal small fiber sensory polyneuropathy (SFSN) [2]. Sudomotor C-fibers are postganglionic, unmyelinated, cholinergic, sympathetic nerves that innervate sweat glands, and SMD is manifested clinically as abnormal sweating leading to skin dryness. Dryness of foot skin as a result of SMD is associated increased risk of foot ulceration (FU) [3]. While peripheral artery disease accounts for an increased risk of FU in only 35 % of cases, DPN contributes to 78 % of the risk of FU, and together with foot deformity and repetitive trauma forms the clinical triad that leads to FU [5, 6]

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