The Clinical Value Of Sympathetic Skin Response In Diabetic Peripheral Neuropathy

Diabetes mellitus is a very common general metabolic disease, which originated by insufficient of insulin secretion, absolutely or opposingly. Diabetic peripheral neuropathy is one of the most frequently complications, it can not be reversible if development, but the morning sings and symptoms of DPN are always fairly delitescence, it is difficult to be judgmented by clinical appearances, so the early diagnosis is very important. The etiopathogenesis of diabetic peripheral neuropathy is still not very clearly up to now, metabolism abnormality induced by hyperglycemia is considered as the most important factor in the pathogenesis of diabetic peripheral neuropathy. It is presumed that it is mainly metabolic neuropathy which associated with hyperglycemias at present, then pathological changes of blood vessel. So electrophysiological diagnosis is used in the clinical diagnosis. Diabetic peripheral neuropathy can involve sensory nerve, motor nerve and autonomic nerve. Sensory nerve fibril and autonomic nerve fibril which with or without medulla are always affected at the early time, in the damage of diabeticperipheral nervous system. The orthodox determination of nerve conduction velocity (NCV) is used to detect the function of the big fibers with medulla, can't reflect the functional status of fibril. Sympathetic skin response is an electrical potential of epidermis, which reflexes the functional status of sympathetic postganglionic fiber, can reflex the convery function of the fibril without medulla and autonomic nerve, can redeem the deficient of NCV. Sympathetic skin response can be procured through many different stimulated methods. The sympathetic nerve sudoriferous fiber of human body, could be actived reflectivitIily, and get records on the skin surface of the palm and planta. The record is the change of epidermis voltage, which concerned with the secretion of sweat glands. Sympathetic skin response is a perspiration movement that controlled by central nervous system, it can be caused by stimulus of endogenous or exogenous, the former such as cough, deep breath and so on, the latter includes electric stimulus, magnetic stimulus, acoustic stimulus and so on. The afferent fibers of reflex arc are differently because of the different stimulus. The different stimulus has different afferent pathway, for an example, the afferent of electric stimulus is skingross sensory fiber with medulla, the one of acoustic stimulus is acoustic nerve, but the efferent pathway is the same, it is constituted by spinal cord, sympathetic preganglionic fibers, postganglionic fiber and sweat glands, posterior hypothalamus and formatio reticularis mesencephali are the most important parts of the reflex center. When the reflex of SSR is damaged, the detection emerges abnormality, the abnormalitily manifestation of latency and amplitudes. The latency of SSR reflexes the transmission time course of the whole reflex arc which causes diaphoretic, and the amplitudes reflexes the density of the sweat glands which have secrete activity. Consequently, it is a reliable indicator to reflex the activity of periphery adrenergic nerve. Recently, the superiority of SSR in early diagnosis is being discovered, is a valuable method in the early diagnosis of Diabetic peripheral neuropathy. The patient of diabetic peripheral neuropathy will get diagnosis and treatment in time according to the determination, in order to improve the prognosis, the quality of life, and provide the proof to evaluate the clinical therapeutic effect. So in this text, the electro neurophysiological data of 60 patients with diabetes mellitus,including motor nerve conduction velocity (MCV) data, sensory nerve conduction velocity (SCV) data and sympathetic skin response (SSR) date, were analyzed retrospectively.[Objective] To observe the clinical value of sympathetic skin response in diagnosing diabetic peripheral neuropathy, especially identify the relationship between SSR,the course of disease and the patients without clinical symptoms of DPN. And research the superiority of SSR.[Methods] The electroneurograms data on 60 diabetes mellitus patients, and 30 healthy volunteers as a comparison, and divided the diabetes mellitus patients into 2 groups by the course of diabetes mellitus :one group≥5 years, the other<5 years. The detection that including motor nerve conduction velocity (MCV), sensory nerve conduction velocity (SCV) and sympathetic skin response (SSR), were analyzed retrospectively. Used the electromyologram equipment from Denmark, all the subjects lying in the bed peaceful and slacken, room temperature is higher than 25 degree. The skin temperature is higher than 32 degree.The routine determination of NCV: median nerve ,ulnarnerve ,common peroneal nerve of motor nerve conduction velocity, median nerve , ulnar nerve ,sural nerve and superficial peroneal nerve of sensory nerves conduction velocity. The detection method and abnormality standard quod vide literature.The routine determination of SSR: electrical stimulating method, stimulate position are peripheral nerve, median nerve is used frequently. Electrical stimulating method is used in the detection of SSR, recorded at the palm of the hand and the planter centre, dorsum manus and dorsum of foot as the reference. Stimulus the median nerve of wrist with the saddle shape stimulating electrode, grounding wire are put between them, the time course of electrical stimulus:0.2ms, band pass: 0.1~100Hz,sensitivity:0.1~2mV/s,sweep speed:1ms/D , quantity of stimulus:10~50mA , interval time>60s,in order to decrease the adaptability; The time course from beginning to the initiation point as the latency,and peak to peak wave amplitude of SSR as the amplitudes.[Results]①There was statistical difference in comparison of the DM group and the control group(all the P values were <0.05);②The latency and amplitudes was no difference between the group≥5years, and the group<5 years, all the P>0.05;③In the two groups, there was statistical difference in comparison of the total abnormity rate to the NCV and SSR abnormity rates (all the P values were <0. 05) . In the group≥5 years, there was statistical difference in comparison of SSR abnormity rate and NCV abnormity rates , all the P < 0. 05. In the group <5 years, there was no difference , all the P>0.05;④In the DM group, there were 11 patients without obviously clinical subjective symptom,6 patient(s55.5%)with the abnormality of SSR, and 2 patients(18.1%)with the abnormality of NCV;⑤In the DM group, there were 6 patients only with the abnormality of NCV, but without the abnormality of SSR.[Conclusion]①The sympathetic skin response are sensitive indices for the diagnosis of DPN.②The correlate between SSR and course is not obviously . Prompt the abnormality of SSR could emerge very early, it may mainly determined by the control condition of blood sugar.③SSR plays an important part in the diagnosis of DPN patients that without clinical symptom.④The detection rate of SSR is higher than that of NCV , especially in early course of diabetes mellitus.⑤SSR can not substitute NCV,the diagnostic sensitivitycan be improved if all the parameters are used together.