Renal functional changes in acute glomerulonephritis in children. A one-year follow-up

Renal function was studied in three patients with post-streptococcal, four patients with IgA and one patient with non-streptococcal proliferative glomerulonephritis (GN) at the onset of the disease and two, six and 12 months later. Renal biopsies were performed at the onset of the disease and 12 months later. Standard clearance techniques were used for the functional studies. The latter were performed during hydropenia and continuous isotonic saline infusion. During hydropenia, the GFR was uniformly depressed shortly after the onset of the disease, but it normalized during the following two months. The filtration fraction was depressed in poststreptococcal GN at the onset and it normalized with the GFR. In IgA GN, the filtration fraction remained within normal limits during the entire course of the illness. The natriuretic response to isotonic saline volume expansion was low in all patients at the onset of the disease, but normalized in post-streptococcal and IgA GN during the one-year follow-up. In spite of normalized renal function, biopsy findings in IgA GN were unchanged 12 months later. An episode of macroscopic hematuria in one patient with IgA GN at the six-month investigation had no apparent effect on renal function.