Page 6 - Canadian Urological Association/Pediatric Urologists of Canada guideline on the investigation and management of antenatally detected hydronephrosis

Capolicchio et al

including a VCUG to exclude PUV. If the postnatal US historical cohorts of symptomatic UPJO prior to the advent
reveals persistent HGHN, these cases should be referred to of maternal ultrasonography would undergo pyeloplasty at
2
a pediatric urologist for immediate consultation. These cases an average age of six years, hence a persistent Grade 3 HN
are most likely to benefit from CAP and should have both a requires active surveillance.
VCUG and MAG3 renal scan. It is worth repeating that the
clinical utility of a VCUG in HGHN is not due to concern SFU Grade 1 and 2, APD <10 mm, LGHN
over UTI, rather it helps to distinguish an obstructive cause
of AHN from one due to VUR, helping to tailor the frequency The timing of the first postnatal US is open to debate and left
and type of serial imaging studies. In the absence of any to the discretion of the treating physician. For cases with ante-
pathology requiring immediate intervention, repeat US and natal APD between 10‒15 mm, the SFU grading is suggested
MAG3 should be performed within three months, although to clarify which followup protocol should be used. Most phys-
a repeat MAG3 is optional if the first exam is normal (Fig. 1). icians will obtain an US within the first months of life and a
If improvement is not seen, close followup should continue followup can be obtained six months later. In the absence
to at least 18 months of age, by which time most childhood of deterioration, followup US can then be performed on an
UPJO becomes apparent. One should keep in mind that annual basis. VCUG and MAG3 are not required. Szymanski

SFU Grade 1–2, APD 7–10 mm* SFU Grade 3–4, APD >15 mm*
3rd trimester 3rd trimester

RBUS first 1–3 months of life** RBUS first 2 weeks of life, CAP

SFU Grade 3–4, APD >15 mm
Normal, SFU Grade 0 SFU Grade 1–2, APD <10 mm
Refer to pediatric urology

Discharge, counsel on Followup US at 6 months,
symptoms of UTI/UPJO thereafter annual US,
no CAP***

VCUG

VUR No VUR

Manage VUR Mag3 lasix renal scan

Abnormal Mag3 –“active Normal DRF and drainage, repeat
surveillance vs. surgery US 3 months, no CAP***
Fig. 1. Algorithm for management of antenatal hydronephrosis. APD between 10 and 15 mm should be managed by the SFU grade. Dilated
**
*
ureters, abnormal bladders, or abnormal renal parenchyma should be imaged sooner. Some authors advocate CAP for LGHN with dilated
***
ureters or abnormal bladders. The risk of UTI is also increased in females and uncircumcised males. APD: antero-posterior renal pelvic
diameter; CAP: continuous antibiotic prophylaxis; LGHN: low-grade hydronephrosis; RBUS: Renal–bladder ultrasound; SFU: Society for Fetal
Urology; UPJO: uretero-pelvic junction obstruction; US: ultrasound; UTI: urinary tract infection; VCUG: voiding cysto-urethrography; VUR:
vesicoureteric reflux.
90 CUAJ • April 2018 • Volume 12, Issue 4