Femoral versus peroneal neuropathy in diabetic children and adolescents--relationships to clinical status, metabolic control and retinopathy.

In order to estimate the prevalence of diabetic neuropathy in proximal and distal peripheral nerves, femoral and peroneal motor conduction was evaluated in 61 diabetic children, adolescents and young adults whose type 1 diabetes had become clinically apparent before the age of 14 years. Femoral motor nerve conduction velocity (FMNCV) in diabetic patients (63.8 +/- 10.4 m/sec) was not significantly different from FMNCV in control subjects (65.6 +/- 7.1 m/sec). By contrast, peroneal motor nerve conduction velocity (PMNCV) in diabetic patients (50.2 +/- 6.9 m/sec) was significantly lower than in controls (54.1 +/- 3.5 m/sec). Distal motor weakness, sensory deficit and absent Achilles reflexes were strongly correlated to impaired motor conduction in peroneal and also in femoral nerve. Peroneal nerve abnormality was negatively correlated with HbA1 levels, while femoral nerve abnormality was positively correlated with the presence of retinopathy. This discrepancy is not fully understood. Age and duration of diabetes were unrelated to femoral or peroneal motor nerve conduction velocity. Our data emphasize the frequent occurrence of subclinical proximal neuropathy in diabetic children and adolescents.