Back to 2014 Fall Congress Meeting Abstracts

BACKGROUND
The 2011 American Academy of Pediatrics (AAP) guideline recommends routine renal and bladder ultrasonography (RBUS) after initial febrile urinary tract infection (UTI) in children 2 to 24 months of age. Voiding cystourethrogram (VCUG) is indicated only if the RBUS reveals hydronephrosis, scarring, or “other findings” that suggest either high-grade vesicoureteral reflux (VUR) or obstructive uropathy. Uroepithelial thickening (UET) of the renal pelvis is a sonographic finding that has been associated with inflammation, prior distention, or VUR; however, the clinical significance and implications of this finding in the setting of childhood UTI are not clear. We sought to determine if UET is one of the “other findings” that suggest high-grade VUR, and thus, warrants further evaluation with VCUG.
METHODS
We retrospectively reviewed all RBUS performed at our institution from January 2004 to December 2013 with the radiographic finding of UET, which was identified by a hypoechoic rim within the renal pelvic wall delineated on each side by a thin hyperechoic line. Of these studies, we cross-referenced patients who also had VCUG, were less than 24 months of age and whose primary indication for RBUS was UTI. The presence of UET, hydroureter, duplex collecting system, and Society for Fetal Urology (SFU) grade of hydronephrosis was recorded for each renal unit. Univariate and multivariate logistic regression models were constructed to identify factors associated with high-grade VUR (defined as grade 3 or higher), and to analyze whether UET is an independent predictor of high-grade VUR. Odds ratio (OR) and 95% confidence interval (95% CI) for prediction of high-grade VUR were estimated.
RESULTS
1799 patients with UET on RBUS were found and of these, 900 had VCUG performed. Among these 900 patients, we identified a total of 167 children less than 24 months old who had UTI as the indication for RBUS for our study population. UET was bilateral in 28% (47/167) of children, and present in 64% (214/334) of all renal units. High-grade VUR was found in 47% (78/167) of all children, and in 40% (86/214) of renal units with UET. On univariate analysis, UET, hydroureter, SFU grade 1, 2, and 3 hydronephrosis were all associated with high-grade VUR; duplex collecting system was not. On multivariate analysis, UET remained an independent predictor of high-grade VUR after controlling for SFU grade and hydroureter (Table).

Univariate Analysis	Prediction of High-Grade VUR
UET	OR 3.43; 95% CI 1.97-5.95
Hydroureter	OR 7.09; 95% CI 3.04-16.53
SFU Grade 1	OR 2.72; 95% CI 1.53-4.85
SFU Grade 2	OR 5.13; 95% CI 2.46-10.67
SFU Grade 3	OR 27.33; 95% CI 5.98-124.96
Multivariate Analysis
UET	OR 2.14; 95% CI 1.16-3.95

CONCLUSIONS
In children less than 2 years of age presenting with UTI, the presence of UET on RBUS is an independent predictor of VUR grade 3 or higher. The 2011 AAP guideline only includes hydronephrosis and scarring on RBUS as indications for VCUG in this setting. Based on this study, UET is another sonographic finding that also warrants consideration of VCUG.