Background: The aims of this study were to determine whether renal pelvis dilation on ultrasound was reliable in predicting vesicoureteral reflux (VUR) and to assess the relationship of other clinical information of VUR in children with urinary tract infection (UTI).
Methods: We retrospectively reviewed clinical data, renal echo, and voiding cystourethrogram (VCUG) results in hospitalized children with their first episode of UTI, aged from 1 month to 5 years, during a 1-year period.
Results: There were 114 children with 228 kidneys eligible for the study. Unilateral pelvis size greater than 8 mm had 2.4 (p = 0.049, 95% CI: 1.0-5.9) and 3.7 (p = 0.025, 95% CI: 1.2-11.3) times greater risk for VUR and severe reflux, respectively. The sensitivity in detecting severe reflux was 27.8%, and the specificity was 90.5%. The positive and negative predictive values in suggesting severe VUR were 20.0% and 93.6%, respectively. The sum of bilateral pelvis sizes greater than 16 mm had higher risk for VUR and severe reflux (4.1 and 4.6 times) and similar specificity and negative predictive value for severe reflux. Age, gender, C-reactive protein, leukocytosis, pyuria and acute pyelonephritis did not show significant relationships to the reflux.
Conclusions: Unilateral pelvis size greater than 8 mm or the sum of the bilateral pelvis sizes greater than 16 mm was associated with VUR, especially severe VUR. The possibility of severe reflux was lower than 10% when the reverse criteria were applied. However, the dilation of the renal pelvis did not predict all VUR precisely. We concluded that VCUG should still be performed in hospitalized children with UTI.