Small fibre neuropathy detected by ultrasound of median nerve in children with type 1 diabetes mellitus is related to glycemic control.

AimThe initial stage of diabetic peripheral neuropathy (DPN) is characterized by the damage of small nerve fibres. High-resolution ultrasound is used to assess the nerve cross-sectional area (CSA), representing these. The aim of our study was to study the influence of metabolic control as measured by HbA1c and body surface area (BSA) on CSA. Method73 children with type 1 diabetes mellitus (T1D) (8-16 years) and 71 healthy controls 8-16 years) underwent ultrasound of the median nerve. The association of CSA with BSA and HbA1c was tested with linear regression models. ResultsIn children with HbA1c >9%, CSA was significantly higher than in controls. In the combined group including all children, CSA was significantly correlated with BSA. In children with T1D, linear models taking these effects of BSA into account showed a highly significant correlation of the CSA with the HbA1c (Regression Coefficient 0.217 (CI 0.073 - 0.361)). ConclusionMedian nerve CSA is related to BSA and HbA1c. When CSA of the median nerve is adjusted for BSA a clear and robust correlation with thicker nerves with higher HbA1c was found. Based on this data, we derived a method for the early prediction of small fibre neuropathy in children with T1D. Highlights- Ultrasound measurement of median nerve thickness is a non-invasive diagnostic marker that can be used for early detection of nerve damage. - Children with type 1 diabetes have a thicker median nerve than healthy controls. - Nerve thickening depends on metabolic control: the worse the HbA1c, the thicker the nerve. - Nerve thickness is measured as the diameter of the median nerve (cross-sectional area, CSA). It represents the damage to the small unmyelinated fibres that are affected in the early stages of diabetic neuropathy (DNP).