What Are the Implications for Ordering VCUG for All Infants with High Grade Prenatal Hydronephrosis?
Mandy Rickard, MN, NP1, Armando J. Lorenzo, MD2, Adriana Dekirmendjian, BHSc1, Natasha Brownrigg, MN, NP1, Jorge DeMaria, MD1, Luis H. Braga, MD1.
1McMaster University, Hamilton, ON, Canada, 2The Hospital for Sick Children, Toronto, ON, Canada.
INTRODUCTION:
Voiding cystourethrogram (VCUG) is often recommended for infants with Society for Fetal Urology(SFU) grade III/IV prenatal hydronephrosis(HN) and/or those with dilated ureters. A recent survey reported lack of uniformity in this practice, particularly for patients without prior history of urinary tract infections(UTIs). Herein we evaluate the yield of vesicoureteral reflux(VUR) detection and determine the risk of subsequent UTIs, to explore the value of this diagnostic practice and merit for routine, universal request for all cases.
Methods
We reviewed our prospectively-collected prenatal HN database of patients 0-24 months from 2008-16(n=571), selecting those with SFU III/IV HN and/or ureteric dilatation and no history of UTI, who underwent VCUG according to our institutional protocol. We excluded children with associated uropathies and those with previous UTI(n=326). Children were segregated in 2 groups (those with hydroureteronephrosis (HUN) (ureter diameter>7mm) and those with isolated HN) and then further stratified them by VUR status (present or not). Outcomes included rates of UTI and subgroup analysis on the rate of VUR in patients with unilateral vs. bilateral HN. Univariate analyses were conducted and stratification was employed to control for confounding.
Results
Of 245 patients, median age at presentation was 2 months(0-21), 193(79%) were male, 172(66%) had isolated HN and 88(34%) had HUN. Mean follow-up time was 28+21 months. In the isolated HN group, 82% had unilateral dilatation and 11% of those had VUR compared to 10% in those with bilateral HN(p=0.92). For children with HUN, 76% had unilateral dilatation and 27% of those had VUR compared with 52% in infants with bilateral dilatation(p=0.03). There was a significant difference in continuous antibiotic prophylaxis (CAP) use between infants with isolated HN and HUN(34% vs. 57%; p=0.02). When we compared rates of UTI, we noted that there was no difference between isolated HN vs. HUN(8% vs. 6%; p=0.62) as well as between infants with VUR vs. those without, regardless of etiology(10% vs. 7%; p=0.34) (Figure 1).
Conclusion
The rate of VUR in patients with isolated HN was low(11%) compared to infants with HUN(33%), however VUR was rarely associated with subsequent development of febrile UTIs in either group. Significantly more children with HUN received CAP, which could provide a protective effect for development of UTIs in this group. Having bilateral involvement did not increase the likelihood of diagnosing VUR in those with isolated HN; but in children with bilateral HUN, the likelihood of finding VUR increased to more than 50%. Therefore, ordering VCUG solely based on laterality of HN appears justified for children with HUN. Based on these data, we propose that a more selective approach can be offered when determining which children with high-grade prenatal HN should be investigated with VCUG and those who would benefit from CAP.
Table 1
| Isolated HN n=172 | HUN n=88 | p value | |
| Age (median) (months) | 2 (0-21) | 2 (0-10) | 0.94 |
| Gender - Male - Female | 134 (78) 38 (22) | 71 (81) 17 (19) | 0.63 |
| Circumcised | 46 (27) | 31 (35) | 0.20 |
| Laterality - Unilateral - Bilateral | 141 (82) 31 (14) | 67 (76) 21 (24) | 0.33 |
| APD baseline (mm) | 15 + 8 | 13 + 9 | 0.07 |
| VUR | 19 (11) | 29 (33) | <0.01 |
| CAP USE - Yes - No - Unknown | 58 (34) 40 (23) 74 (43) | 50 (57) 14 (16) 24 (27) | 0.02 |
| UTI | 14 (8) | 5 (6) | 0.62 |
| Surgery | 59 (34) | 13 (15) | <0.01 |
| Maximum follow up (months) | 29 + 21 | 26 + 22 | 0.29 |
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