Page 5 - Canadian Urological Association/Pediatric Urologists of Canada guideline on the investigation and management of antenatally detected hydronephrosis

Guideline: Antenatally detected hydronephrosis

raphy can be useful when multiple levels of obstruction are Table 4. Incidence of UTIs in patients with hydronephrosis 42
suspected, such as combined UPJO and UVJO. Cystoscopy No. UTI (%) p OR 95% CI
can help for evaluation of ectopic ureters and ureteroceles Sex
as can magnetic resonance urography (MRU). MRU can Male 67 (19) 0.8 0.93 0.51–1.71
be especially helpful with the abnormal anatomy found Female 16 (20)
in duplication anomalies, renal ectopy and renal fusion Obstruction
anomalies. This type of abnormal anatomy is often found Yes 50 (39) 0.001 5.23 3.148–8.67
in children with the VACTERL association or cloacal anom- No 33 (11)
alies. Non-invasive studies, such urinary biomarkers (e.g., Hydroureter
transforming growth factor beta) are still under investiga- Yes 37 (47) 0.001 6.00 3.49–10.32
tion, but hold promise in predicting those cases that could No 46 (13)
37
deteriorate and require closer followup. Similarly, the field Uretetocele
of functional renography holds promise both with nuclear Yes 10 (59) 0.001 6.65 2.45–18.06
38
medicine and positron emission tomography. GFR renal No 73 (18)
39
scan may be helpful in cases of severe bilateral HN. HN grade
I 6 (4)
Continuous antibiotic prophylaxis (CAP) II 13 (14) 0.001 4.15 1.52–11.32
III 26 (33) 0.001 12.67 4.95–32.47
CAP has empirically been recommended for newborns with IV 38 (40) 0.001 16.93 6.80–42.15
prenatal HN in an attempt to reduce the rate of UTI dur- CI: confidence interval; HN: hydronephrosis; OR: odds ratio; UTI: urinary tract infection.
ing the first two years of life. However, the AUA, SFU and
Canadian Urological Association (CUA) all acknowledge megaureter patients within the first six months of life and
that use of CAP for prevention of UTI in infants with pre- that circumcision and CAP significantly decreased their
44
natal HN has been based on low levels of evidence. Not infection rates. Other studies with retrospective design
45
surprisingly, this lack of high-quality evidence has resulted in have reported similar findings. In addition, females and
practice variability for CAP use. According to the 2010 SFU uncircumcised males with prenatal HN have also exhibited
consensus statement on HN, CAP should be recommended a much higher risk of UTI. 46
only for infants with HGHN and those with VUR. 1 The role of prophylactic antibiotics in children with pre-
Given the uncertainty over CAP use in prenatal HN natal HN who are awaiting completion of postnatal inves-
patients, a systematic review was conducted in 2013 to sum- tigations is controversial. While it is believed that CAP may
marize the latest evidence regarding CAP use in children prevent UTI in children with prenatal HN, it has yet to be
with prenatal HN. Data of nearly 4000 patients from 21 proven. A randomized, controlled trial comparing trimetho-
full-text articles demonstrated that pooled UTI rates were prim to placebo in infants with SFU Grades 3‒4 HN is cur-
47
four times higher for HGHN patients when compared to rently underway in order to answer this question. Therefore,
those with LGHN. In children with LGHN, UTI rates were some authors suggest institution of CAP at birth, while others
equivalent, regardless of their CAP status (2.2% on CAP vs. recommend a low threshold for investigation and treatment
2.8% not on CAP). On the contrary, HGHN patients on CAP of a suspected UTI. Commonly used prophylaxes in the
experienced fewer UTIs than those not on CAP (14.6% vs. neonate include amoxicillin, cephalexin, and trimethoprim.
28.9%; p<0.01), suggesting that CAP may be beneficial in Trimethoprim-sulfamatholxazole and nitrofurantoin should
this population. The estimated number needed to treat was NOT be used in the neonate because of the respective risk
seven, meaning that a clinician would offer CAP to seven of kernicterus and hemolytic anemia.
patients with HGHN in order to prevent one UTI. A more
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recent systematic review confirmed that there seems to be Followup protocols
value in providing CAP to infants with HGHN. 41
The suggestion has also been made that the presence
of hydroureter or ureterocele carries a higher risk of UTI SFU Grades 3 and 4, APD >15 mm, HGHN
(Table 4). 42
The subgroup of patients with primary non-refluxing The initial postnatal RBUS should be done as soon as feas-
megaureters (hydroureteronephrosis) has been studied in ible after Day 2 of life, as this represents the cohort most
greater detail. These infants had a much higher febrile UTI likely to require surgery and to experience UTI. The likeli-
rate than those with isolated HN (19/59 [32%] vs. 12/218 hood of Grade 4 HN undergoing a pyeloplasty is up to
35
[6%]) according to a prospective study. Moreover, another 75%. Most centres recommend the US within two weeks
43
study demonstrated that febrile UTIs developed in 34% of of life. Bilateral HGHN requires more urgent consultation,

CUAJ • April 2018 • Volume 12, Issue 4 89