Back to 2016 Fall Congress

BACKGROUND:
Imaging procedures such as voiding cystourethrogram (VCUG) requiring catheterization and retrograde instillation of contrast entail an inherent risk of post-procedural urinary tract infection (ppUTI). Previous studies examining rates of ppUTI after VCUG have used variable definitions of UTI, and reported rates have also been highly variable (0-42% with differing antibiotic regimens). The aims of this study were to (1) determine the risk of a symptomatic ppUTI after VCUG and (2) evaluate specific predictors of ppUTI.
METHODS:
We conducted a retrospective cohort study of children <18 years old undergoing VCUG from 01/2012-12/2013 at a freestanding children’s hospital. Data were obtained via manual chart abstraction from the electronic medical record. Patients with neurogenic bladder and without follow-up after VCUG were excluded. Descriptive statistics were used for demographic and clinical characteristics. Symptomatic ppUTI within 7 days of VCUG was measured. Fisher’s exact test was to evaluate for predictors of ppUTI.
RESULTS:
909 patients (55% female, median age 1.2 years [range 0-17]) underwent 1,025 VCUGs. The most common indications for VCUG were febrile UTI (338/1025, 33%), history of vesicoureteral reflux (VUR) (269/1025, 26%,), and prenatal hydronephrosis (249/1025, 24%). 53% of patients were on antibiotics at the time of VCUG and 76% had a known urologic diagnosis prior to the procedure (56% hydronephrosis, 30% VUR, 5% ureterocele, 2% posterior urethral valves). 18% had a clinical UTI within the 30 days prior to VCUG, including 14% with a documented positive urine culture. The VCUG was normal in 56% of cases. The most common abnormal results included VUR and ureterocele (82% and 7% of abnormal tests, respectively). Only 13 patients had a ppUTI (1.3%; 95% confidence interval 0.6-2.0%). Of these, 10/13 (77%) had a documented febrile UTI, and 9/13 (69%) had a documented positive urine culture of >10,000 CFU/mL. Among patients presenting with a symptomatic UTI within 7 days after VCUG (ppUTI), most were already on antibiotics (12/13, 92% vs. 532/1012, 53%; p=0.004); all had a known urologic comorbidity, including VUR or hydronephrosis (13/13, 100% vs. 764/1012, 75%; p=0.046); and nearly all had an abnormal test result (12/13, 92%, vs. 443/1012, 43%; p=0. 0004) compared with those without ppUTI. Of these, 11/12 (92%) had VUR, 11/11 (100%) grade III or greater. Conversely, of all patients with Grade III or greater VUR, only 5% (11/224) had a ppUTI.
CONCLUSIONS:
The risk of ppUTI after VCUG is low. In this study, presence of a urologic diagnosis such as VUR or hydronephrosis was associated with ppUTI; only one patient with a normal VCUG developed a ppUTI. These data suggest that routine antibiotic prophylaxis is not necessary prior to a VCUG in the absence of another indication for antibiotics. However, increased vigilance for ppUTI is warranted after VCUG in children with significant anatomic abnormalities, particularly high-grade VUR.