Urinary Tract Infection after Voiding Cystourethrogram
Emilie K. Johnson, MD, MPH1, Neha R. Malhotra, MD2, Rachel Shannon, BS1, Jared Green, MD1, Angela Shurba, MPH1, Cynthia K. Rigsby, MD1, Jane L. Holl, MD, MPH3, Earl Y. Cheng, MD1.
1Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA, 2University of Illinois at Chicago, Chicago, IL, USA, 3Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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.
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.
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.
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.
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