Renal functional reserve in children with a previous episode of haemolytic-uraemic syndrome.

Renal function [creatinine clearance (CCr)] and renal functional reserve (RFR) was measured in 16 children who had had haemolytic-uraemic syndrome (HUS) an average of 6.6 +/- 0.72 years previously. All patients had normal plasma creatinine and blood pressure and only 3 had proteinuria, which was mild in every instance. Patients were studied whilst ingesting three diets which provided an average of 1.5, 2.1 and 3.1 g protein/kg body weight per day, respectively. Diets were administered over three consecutive periods of 7 days each and CCr was measured on the 7th day of each diet. Values tended to correlate with protein intake. They were in the normal range when patients were taking 1.5 and 2.1 g protein diets and increased markedly in 13 of the 16 patients (P less than 0.001) when they ingested the high-protein diet (3.1 g). The effect on glomerular filtration rate (GFR)--measured by CCr and inulin clearance (Cin)--of an acute oral protein load was studied in 12 of the HUS patients and four control subjects. In the control periods, prior to the protein load, values for CCr were similar in the HUS and control subjects (104.0 +/- 11.0 vs 121.6 +/- 10.1 ml/min per 1.73 m2, NS). However Cin values were significantly reduced in HUS patients (59.5 +/- 9.2 vs 102.7 +/- 12.4 ml/min per 1.73 m2, (P less than 0.025). The CCr/Cin ratio in the patients averaged 2.10 compared with 1.13 in controls. Acute protein loading was accompanied by an increase in Cin in all controls but in only 8 of the 12 patients.(ABSTRACT TRUNCATED AT 250 WORDS)