Clinical and morphological aspects of nephrotic syndrome in perimembranous, focally sclerosing and membrano-proliferative glomerulonephritis.

The following data was obtained by morphometric and photometric microscopic studies of renal biopsies from 140 patients with idiopathic perimembranous glomerulonephritis, 108 patients with focally sclerosing glomerulonephritis and 50 patients with membranoproliferative glomerulonephritis and correlation of the results obtained with available clinical data: 1. In all three diseases proteinuria and serum protein concentration show no tendency to stabilization in spite of increasing renal insufficiency. 2. With increasing renal insufficiency the proximal tubular cells become increasingly atrophic. 3. Protein resorption through the proximal tubulus cells becomes increasingly diminished with advancing renal insufficiency. It is concluded from the present data that proteinuria, which is primarily glomerular caused, is increased by increasingly diminished resorption of proteins in the tubulus system with increasing renal insufficiency. In this way, even under conditions of advanced renal insufficiency with reduced GFR, large amounts of proteins can be excreted and a nephrotic syndrome can persist to a stage of renal insufficiency.