[Diagnosis of diabetes mellitus based on the renal biopsy]

In a total of 1499 representative renal biopsies 30 displayed morphological changes suggesting diabetic nephropathy. Six patients had clinically diagnosed diabetes at the time of biopsy, 20 according to the bioptic finding, and in four patients the examination did not confirm diabetes. The authors describe the morphological vascular changes in particular the cumulation of masses resembling the mesangial matrix and basal membranes, as well as hyaline lesions, their development, site and combinations. In the author's opinion the most reliable sign of early diabetic nephropathy is thickening of the glomerular basal membrane. They draw attention to the non-specific character of the morphological finding and the necessity to diagnose diabetes mellitus by clinical and in particular by laboratory methods.