Electrophysiological and clinical study of type-2 diabetic patients with short duration of disease and normal generalized nerve conductions

Aim. To evaluate the presence of clinical and electrophysiological abnormalities in type-2 diabetic patients with short duration of diabetes and normal systemic nerve conduction. Methods. Twenty-three consecutive type-2 diabetes patients (age 59.1±8.1 years, range 43-75 years, duration of diabetes 6.6±2.6 years, range 3-11 years) in good metabolic balance, of whom 15 were hypertensive on antihypertensive therapy and 8 were normotensive. Patients were regularly followed in the outpatient clinics. Serum C-peptide, lipids, glycosylated haemoglobin, glucose, Body Mass Index (BMI), and blood pressure were regularly monitored. A detailed neurological examination including a questionnaire on symptoms was performed followed by a complete electrophysiological study including sensory and motor nerve conduction studies and electromyography (EMG). Results.the whole population motor conduction in both upper (median and ulnar) and lower (peroneal and posterior tibial) limbs and sensory conductions of the median, ulnar, and sural nerve were within normal range. Patients were classified in the following groups: I) no clinical symptoms and signs and no electrophysiologic abnormalities (N=3, age 50.0±5.7 years, diabetes duration 7.3±3.3 years); IB) no clinical symptoms and signs but abnormal EMG (N=5, age 66.4±6.5 years, duration of diabetes 9.0±1.1 years); II) presence of clinical symptoms and signs and abnormal electrophysiological investigation (N=12, age 59.2±5.7 yrs, diabetes duration 5.9±2.2 yrs with chronic neurogenic disorder without active denervation on the EMG; N=3 cases with chronic neurogenic pattern with active denervation, age 55.3±8.0 yrs, diabetes duration 3.5, 6.0, and 4.0 yrs respectively). We observed a higher frequency of hypertension in diabetics with axonal damage than in patients with normal systemic EMG and ENG and in patients with "mixed" pattern on EMG, x²=3.725, P=0.05. Conclusion. These results demonstrate a link between high sensitivity of the electrophysiologic studies and presence of a great variability of neurologic clinical symptoms and signs mainly in multiple associations. Both nerve conduction studies and EMG showed no generalized abnormalities and no clinical symptoms and signs only in 3 patients (13% of population) and presence of neurophysiologic abnormalities in 77% and some symptoms or signs in 65% of population studied with relatively short duration of diabetes.