Clinical And Electrophysiological Study Of Peripheral Nerve Function In Different Glycometabolism States

Research purposes and contents:According to the glucose metabolic function,human glycometabolism status are defined as diabetes mellitus(DM),pre-diabetes mellitus(Pre DM)and normal level.Peripheral neuropathy(PN)is one of the three most common complications of diabetes mellitus(DM).It seriously affects the quality of life of patients,increases the family and social economic burden.Finding the peripheral nerve damage in a early stage would help the glycometabolism disfunction people benefit from the early treatment.Studies have proved that there are 10% of patients with DM have already suffered the problem of PN when their DM diagnosed.This drove a increasing attention,whether there is peripheral nerve damage in the pre-diabetes stage should be clearly.Prediabetes mellitus(Pre DM),including impaired fasting glucose(IFG)and impaired glucose tolerance(IGT),is an intermediate condition in which blood glucose is higher than normal and below the threshold for diabetes.Annual convertion rate from Pre DM to diabetes is 5-10%.In China there will have148.2 million people with pre-diabetes in the year 2010.The peripheral nerve damage in the people with Pre-DM demand to be more concerned,and the degree of Peripheral neuropathy existed in the people with IGT have been identified in some studies,even the condition is not much severe as that in the patients with diabetic.By now,the clinical nerve score was mainly used to evaluate the function of the peripheral nerves in the people with the problem of glycometabolism in many researches,rather than the neuroelectrophysiological method,which is the gold standard for the diagnosis of PN.In the present study,the electrophysiological examination combined the clinical scoring were performed to evaluate the peripheral nerves function of the patients with diabetes mellitus and pre-diabetes mellitus,to explore the prevalence and clinical features of peripheral neuropathy in the people with the different glycometabolism status.To provide the evidence for the preventing PN in the patients with DM.Motor nerve conduction test(MCS)and motor unit number estimation(MUNE)were used to evaluate the function of motor fibers.Sensory conduction test(SCS),Skin sympathetic response(SSR)and contact heat pain evoked potential(CHEP)were performed to assess the function of sensory fibers.To investigate the prevalence and damage characteristics of peripheral neuropathy in patients with diabetes mellitus and pre-diabetes mellitus,to detect and prevent the peripheral neuropathy in patients with pre-diabetes mellitus and diabetes mellitus.Research Methods:(1)Participants: 240 patients with DM and 120 people with Pre-DM were enrolled,thesubject were fulfilled with the diagnostic criteria of diabetes mellitus or the classification criteria of glycometabolism established by the World Health Organization in 2006.According wether they have the symptoms of peripheral neuropathy,the DM patients were further divided into two groups: DM asymptomatic group(n:120),DM symptomatic group(n:120);The Pre-DM group was further divided into IFG(n: 37)and IGT group(n: 83).There were 120 healthy volunteers recruited in as the control group.The subjects in the different groups were matched by sex and age.(2)The fasting blood glucose and OGTT of all subjects were recorded,and the disease course of diabetes,blood pressure,blood lipids(triglycerides,cholesterol,LDL-C,HDL-C),BMI were measured and recorded.(3)the Michigan Neuropathy Screening Scale(MNSI)and the Toronto Clinical Scoring System(TCSS)performed to all the subjects by the same neurologist.(4)The NCS of the median nerve,ulnar nerve,posterior tibial nerve,common peroneal nerve andsural nerve,MUNE of thenar muscle and abductor digitorum brevis were used to evaluate the large fibers,and the SSR of limbs,the CHEP of leg and dorsum of hand were used to explore the small fibers.Research Findings:(1)Compared with the control group,the MNSI score and TCSS score of the Pre-DM group increased significantly(P < 0.05);compared with the Pre-DM group and the control group,the MNSI and TCSS of the DM group increased further(P < 0.05).The abnormal rates of MNSI score(MNSI > 2)in DM group,Pre-DM group and control group were 33.3%,18.3% and 6.7%,respectively;the abnormal rates of TCSS score(TCSS > 6)were 40.0%,25.0% and 10.0%;the abnormal rates of NCS were 48.3%,22.5% and 0%,respectively;and the abnormal rates of SSR were 75.0%,39.2% and20.0%.(2)The incidence of impaired or disappeared ankle reflex was 33.3%(40/120),the incidence of clinical symptoms(pain,numbness,burning sensation)was 16.7%(20/120),the incidence of impaired or absent vibration of big toe was 20.8%(25/120),and the incidence of impaired or absent monofilament pressure was 19.2%(23/120).The incidence of impaired or disappeared ankle reflex was 66.7%(180/240),clinical symptoms(pain,numbness,burning sensation)was 33.3%(80/240),the incidence of impaired or absent vibration of big toe was 41.2%(100/240),and the incidence of impaired or absent monofilament pressure was39.6%(95/240).Compared with Pre-DM,the incidence of clinical symptoms in group DM rised,and the difference was statistically significan.(3)NCS as the gold standard,the sensitivity and specificity of MNSI were 75% and97% in patients with Pre-DM,52% and 84% in patients with DM.The sensitivity and specificity of TCSS were 89% and 95% in patients with Pre-DM,69% and 87% in patients with DM.(4)When compared the age,sex,BMI,waist circumference,blood pressure,blood glucose,blood lipids and course of disease in the subjects with or without NCS abnormal,It was found that in Pre DM group,the age and the 2-hour postprandial blood glucose were higher in the subjects with abnormal NCS,but in DM group,only the course of disease was prolonged.(5)Compared with the control group,the SNAP amplitude of the sensory nerve action potential of the posterior tibial and sural nerves in the Pre-DM group was significantly lower(P < 0.05),and there was no significant difference in the indexes of motor conduction and MUNE between the two groups(P > 0.05).The amplitude of P wave decreased,the amplitude of CMAP of posterior tibial nerve and common peroneal nerve decreased,and the number of MUNE of abductor digitorum brevis muscle of small finger reduced.(6)According to the results of motor nerve conduction,186 patients with DM were divided into normal motor conduction group(MCS-N)and abnormal motor conduction group(MCS-A).Compared with the control group,the number of MUNEin the abductor digitorum minimi and abductor digitorum brevis muscles in the MCS-N group was decreased(P < 0.05),and the number of small fingers in the MCS-A group was significantly lower(P < 0.05).The number of MUNE of abductor and abductor digitorum brevis was further reduced.(7)The SSR amplitude of upper and lower limbs decreased in the Pre-DM group,compared with the control group;the amplitude of CHEP stimulated by hand back and calf decreased significantly(P < 0.05);compared with the control group and the P re-DM group,the SSR latency of lower limbs prolonged,the amplitude of SSR of upper and lower limbs further decreased;the amplitude of CHEP stimulated by hand back and calf decreased significantly(P < 0.05).Academic meaning(P<0.05).(8)According to the results of electrophysiological examination,the nerve function were graded as follows: first grade: NCS,SSR were normal;second grade: NCS normal,SSR abnormal;third grade: NCS abnormal,SSR normal / abnormal.MNSI and TCSS scores increased with the with the impairment grade in pre-diabetic and diabetic patients.(9)DM group was divided into DM symptomatic group and DM-asymptomatic group.Compared with the control group,the SNAP amplitude of median nerve,ulnar nerve,posterior tibial nerve and sural nerve decreased,and the MUNE number of abductor digitorum brevis and abductor digitorum minimi decreased in DM asymptomatic group(P < 0.05).The amplitude of CMAP,motor conduction velocity of common peroneal nerve and the number of MUNE in abductor digitorum brevis and abductor digitorum minimi decreased significantly(P < 0.05).(10)The SSR amplitude of upper and lower limbs in DM asymptomatic group was lower compared with the control group;the amplitude of CHEP stimulated by hand back and leg was lower(P < 0.05);Compared with the control group and DM asymptomatic group,the amplitude of SSR of upper and lower limbs in DM asymptomatic group was further reduced;the amplitude of CHEP stimulated by hand back and leg was even lower..(11)Pre-DM was further divided into IFG group and IGT group.MNSI score,TCSS score,NCS abnormality rate and SSR abnormality rate were 8.1%,18.9%,13.5% and29.7% respectively in IFG group and 22.9%,27.7%,26.5% and 43.4% in IGT group.(12)Compared with the control group,SNAP amplitude of sensory nerve action potential of tibial posterior nerve and sural nerve decreased in IGT group,and MUNE of abductor digitorum brevis muscle and abductor digitorum minimi muscle had no statistical difference;there was no statistical difference in nerve conduction parameters and MUNE of abductor digitorum brevis muscle and abductor digitorum minimi muscle between IFG group and control group.(13)Compared with the control group,the amplitude of lower extremity SSR decreased in IFG group,the amplitude of CHEP stimulated by hand back and leg decreased,the amplitude of upper and lower extremity SSR stimulated by IGT group decreased,and the amplitude of CHEP stimulated by hand back and leg decreased.(14)According to the results of NCS and SSR,IGR patients were divided into normal SSRN group(73 cases),abnormal SSR group(47 cases),normal NCS group(93 cases)and abnormal NCS group(27 cases),and the results of CHEP were compared.Compared with the control group,the amplitude of CHEP was decreased in the SSRN group,and the amplitude of CHEP was decreased in the SSRA group compared with the control group and the SSSRN group.Compared with the control group,the amplitude of CHEP was decreased in the NCSN group,and the amplitude and latency of CHEP were prolonged in the NCSA group.Research Conclusions:(1)Pre-DM patients with peripheral neuropathy,the prevalence of MNSI,TCSS,NCS,SSR were 18.3%,25.0%,22.5%,39.2%,that in the DM patients,were 33.3%,40.0%,48.3%,75.0% respectively,MNSI,TCSS scores and electrophysiological methods were better consistent;Compared with MNSI,TCSS showed a better sensitivity and specificity when tevaluate peripheral neuropathy in people with Pre DM or DM.(2)the higher 2-hour postprandial blood glucose was the risk factor of the neuropathy in Pre DM,and the course of disease was associated with neuropathy in patients with DM.(3)Neuroelectrophysiological method is helpful to early detect of peripheral neuropathy;composed axonal damage of small fibers and sensory nerve fibers of lower extremities made the mainly problem of the peripheral neuropathy in Pre DM.In DM peripheral neuropathy,axon and myelin were spared difficult,whatever in thesmall fibers,sensory fibers of upper extremities and motor fibers of lower extremities.Neuroelectrophysiology were sensitive to the neuropathy at the sub-clinical stage,and is helpful for patients to get early treatment.(4)The incidence of nerve damage in patients with IGT was higher than that in patients with IFG;electrophysiological methods could detect peripheral nerve damage earlier than clinical scores assesee.In IFG patients,only small fibers were damaged,whereas in IGT patients,large and small fibers were damaged,mainly small fibers and sensory nerve fibers of lower extremities,showing axonal damage and length dependence.(5)MUNE can detect peripheral nerve motor fiber damage earlier than nerve conduction test,and CHEP can detect peripheral nerve small fiber damage earlier than SSR.