Nerve conduction studies in patients with type 2 diabetes mellitus in Basrah

Abstract

Background: Diabetes mellitus has an effect on the peripheral nerves. Such effect may start as asymptomatic peripheral neuropathy. Objectives: To assess the role of electrodiagnostic study in the diagnosis of patients with different types of diabetic peripheral neuropathy (DPN) and evaluate the usefulness of it in early detecting diabetic peripheral neuropathy in asymptomatic patients and to correlate the findings of nerve conduction study in patients with asymptomatic diabetic peripheral neuropathy with various risk factors. Subjects and Methods: subjects were allocated into three groups: 50 normal (non-diabetics apparently healthy subjects without peripheral neuropathy), 50 asymptomatic DPN patients and 50 symptomatic DPN patients. Clinical questionnaire, blood sugar, neurological examination and nerve conduction studies were performed for each subject. Results: This study showed that the prevalence of positive nerve conduction studies was 58% in asymptomatic diabetic patients, 100% for symptomatic diabetic patients and negative for control. The positive nerve conduction study findings in asymptomatic diabetic patients involved sensory more than motor fibers and the lower limbs nerves were affected more than that of the upper limbs. The most commonly involved nerve is the sural nerve sensory fiber which was more prevalent in old age patients (87.5%), patients with longer duration of diabetes (81.8%), over weight (71.4%), patient taking only oral antihyperglycemic drugs (76.9%) and in diabetic patients with poor glycemic control (84.2%) (86.3%) in fasting blood glucose (FBG) and HbA1c respectively. Using the logistic regression, only oral antihyperglycemic drugs (without insulin) and poor control HbA1c were significant predictors of abnormal nerve conduction. Conclusion: Even in asymptomatic patients, nerve conduction studies show diffuse changes, in a predictable pattern. Electrophysiological finding correlate with age, duration of disease, glycosylated hemoglobin levels, fasting blood glucose, type of the treatment if only oral antidiabetic and body mass index.