Estimation of Renal Functional Reserve in Children with Different Grades of Vesicoureteric Reflux.

BACKGROUND: Vesicoureteric reflux (VUR) is one of the most common anomalies encountered in pediatric urology. The concept of renal functional reserve (RFR) as the ability of the kidney to increase glomerular filtration rate (GFR) following a protein load was introduced in the 1980s.

AIM: This study aims to evaluate RFR using 99 Tc diethylenetriamine pentaacetic acid (DTPA) as the filtration agent for GFR estimation in children with VUR.

MATERIALS AND METHODS: RFR was estimated in 53 children, of which 31 patients had unilateral VUR (Group I) and 22 patients had bilateral VUR (Group II), by subtracting baseline GFR from stimulated GFR following an intravenous protein load. GFR was determined by double compartment-2 sample method using 99 Tc DTPA radioisotope as the filtration agent. Both the groups were further subgrouped into low-grade (IA, IIA) and high-grade VUR (IB, IIB).

RESULTS: The RFR was significantly lower in unilateral high-grade VUR (Group IB) as compared to unilateral low-grade VUR (Group IA) ( P = 0.024). RFR was significantly lower in bilateral high-grade VUR patients (IIB) as compared to unilateral low-grade VUR group (IA) ( P = 0.0226). Furthermore, the stimulated GFR shows very strong correlation to baseline GFR in both major groups ( r = 0.9659 and P = 0.001 in Group I and r = 0.9856 and P = 0.001 in Group II) concluding that the baseline GFR and the stimulated GFR increase or decrease in tandem in both the groups.

CONCLUSION: The RFR is impaired in children with both unilateral high-grade VUR and bilateral high-grade VUR while it is relatively preserved in unilateral low-grade VUR and bilateral low-grade VUR.