Primary vesicoureteral reflux detected in neonates with a history of fetal renal pelvis dilatation: a prospective clinical and imaging study.

OBJECTIVE: To assess the clinical outcome and imaging features of neonatal primary vesicoureteral reflux (VUR). STUDY DESIGN: We prospectively followed 43 infants with primary VUR identified from among a cohort of 497 infants with fetal renal pelvis dilatation. Postnatal renal ultrasound (US) examinations were performed at 5 days and 1, 3, 6, 12, and 24 months of life. Voiding cystourethrography was performed in the neonatal period and repeated at 12 and 24 months when VUR was persistent. Two radioisotopic examinations, including a 99mTc-MAG3 renogram and a plasma clearance of Cr-51 EDTA, were performed in all children with high-grade reflux. RESULTS: The incidence of primary VUR in our study group was 9%. Among the 43 patients followed, 11 (26%) had high-grade (IV-V) VUR and 32 (74%) had low-grade VUR. Resolution of reflux occurred in 2 of 11 (18%) patients with high-grade VUR and in 29 of 32 (90.6%) patients with low-grade VUR at age 2 years (P < .001). At age 2 years, 91% of the low-grade refluxing kidneys were normal on US, compared with only 35% of the high-grade refluxing kidneys. Split renal function was within normal range and single-kidney GFR was significantly increased in 13 of the 17 high-grade refluxing kidneys during follow-up. Furthermore, a strong association between dysplasia on US and poor renal function outcome was found. CONCLUSIONS: In most infants with VUR, the reflux is of low grade and resolves rapidly. In those children with high-grade VUR, spontaneous resolution is rare at age 2 years, but persistent reflux rarely impairs the maturation of renal function.

Evolution of individual renal function in children with unilateral complex renal duplication.

OBJECTIVE: To assess the evolution of individual renal function during the maturation process in terms of single kidney glomerular filtration rate (SKGFR) and split function in children with unilateral complex renal duplication. STUDY DESIGN: We retrospectively reviewed the records of 44 children with unilateral complex duplex kidney. All affected kidneys had a poor or nonfunctioning dysplastic moiety, 28 in the upper pole and 16 in the lower pole. At least 2 radioisotopic examinations, including a 99mTc-mercaptoacetyltriglycine (99mTc-MAG3) renogram and a plasma clearance of 51Cr-ethylenediaminetetraacetic acid (Cr-51 EDTA), were performed in all children, the first one performed at a median age of 3 months (range 2 to 15 months) and the last one at 24 months (range 12 to 120 months). They allowed a precise estimation of split renal function, overall glomerular filtration rate (GFR), and SKGFR. RESULTS: Mean overall kidney GFR increased significantly between the two measurements from 63 +/- 12.7 mL/minute/1.73 m2 to 95 +/- 21 mL/minute/1.73 m2 (P <.0001). SKGFR of the duplex side similarly increased from 26 +/- 7.7 mL/minute/1.73 m2 to 38 +/- 12.6 mL/minute/1.73 m2 (P <.0001). In terms of split function, the affected kidney had a remarkable stable function between the two measurements, 40% +/- 8.6 and 39% +/- 8.3 (P=.94), respectively. However, cases with the lowest initial split function (<30%) had the lowest initial SKGFR and the worst further evolution. CONCLUSION: In children with unilateral complex renal duplication, we found on the affected side a significant increase of SKGFR because of renal maturation, whereas mean split function remained stable during follow-up.