Renal hemodynamics in minimal change nephrotic syndrome in childhood

Renal hemodynamics were studied in 16 children with biopsy-verified minimal change nephrotic syndrome. Clearances of inulin and PAH (CPAH) were performed during proteinuric and non-proteinuric phase. Glomerular filtration rate (GFR) and filtration fraction (FF) were found significantly decreased during proteinuric phase compared to controls., while CPAH was within normal limits. A significant correlation was found between GFR and serum albumin concentration during proteinuric phase. GFR and FF increased significantly to normal and super-normal values respectively in those patients restudied in non-proteinuric phase, while CPAH remained unchanged. It is concluded that the normal CPAH during proteinuric phase contradicts hypovolemia as the main cause of the simultaneously reduced GFR. The low GFR is suggested to be caused by a reduced glomerular permeability and/or a reduced filtering surface area.