Renal functional reserve and microalbuminuria excretion in vesicoureteral reflux after surgery correction

The acute effect of an oral protein load on glomerular filtration rate-renal functional reserve (RFR)- and albumin urinary excretion were evaluated in 9 patients with bilateral vesicoureteral grade IV reflux after surgical correction (Group I) and the results compared with 9 children with repeated urinary infection without reflux (Group II) and 6 healthy controls of similar age (Group III). Intravenous urography, performed in the year of the study, revealed renal scarring in 10 kidneys in Group 1 and 2 in Group II. All of them had normal values of plasma creatinine. Basal inulin clearance was significantly lower in vesicoureteral reflux patients. Good correlation was found between parenchymal area of both kidneys and baseline inulin. Following protein load an increase in creatinine and inulin clearance was recorded in urinary infection and control children. No change post load was observed in reflux patients. Microalbuminuria excretion was significantly higher in children with surgical correction during the control period. No changes were observed after load in any of the groups. We conclude that patients who had had bilateral vesicoureteral reflux grade IV showed an impaired renal response to a protein load. Long-term follow-up studies will confirm the value of this test for estimating the risk of further renal function deterioration in reflux nephropathy.