Impact of impaired glucose regulation on the functions of large and small fibers of peripheral nerves

Authors: NA LIU, JING ZHANG, ZHECHENG ZHANG, JU ZHU, LI TIAN, QIAN LI, XIANZHU ZENG

Abstract: Background/aim: This article analyzes the incidence and characteristics of peripheral neuropathy in patients with impaired glucose regulation (IGR). Materials and methods: A total of 120 IGR patients and 60 healthy controls were enrolled. All subjects underwent nerve conduction study (NCS) of large fibers and skin sympathetic response (SSR) and contact heat pain evoked potential (CHEP) testing of small fibers with a Medtronic Keypoint machine (Medoc Ltd., Israel). IGR patients were evaluated using the Michigan Neuropathy Screening Instrument (MNSI). Results: The abnormal rates (MNSI >2) in IGR patients and NCS and SSR evaluations were 18.3%, 22.5%, and 39.2%, respectively. All abnormal NCS findings were accompanied with abnormal SSR findings. Compared with the control group, the sensory nerve action potential wave of the posterior tibial and sural nerve was decreased in the IGR group (P = 0.01, P = 0.00), the SSR wave was reduced in the upper and lower limbs (P = 0.002, P = 0.00), and the CHEP wave was decreased in opisthenar and shank (P = 0.00). Compared with the control group, the CHEP wave was decreased in the shank in the normal SSR group (P < 0.05) and in the opisthenar and shank in the normal NCS group (P < 0.05). Conclusion: : IGR patients have peripheral neuropathy characterized by impaired functions of large and small fibers focused on small fiber and lower limb sensory nerves. CHEP can detect small fiber damage earlier than SSR and NCS.

Keywords: Impaired glucose regulation, peripheral neuropathy, nerve conduction, skin sympathetic response, contact heat evoked potential

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