Incomplete bladder emptying is associated with febrile urinary tract infections in infants

ObjectiveTo investigate lower urinary tract dysfunction in pre-toilet trained infants with and without history of febrile UTI (f-UTI).Materials and MethodsPre-toilet trained infants with f-UTI (Group 1) from pediatric nephrology and urology clinics, and those without f-UTI (Group 2) from infant-care centers were enrolled for the present study. Infants in Group 1 underwent four-hourly (4-H) observations for at least one month after treatment for UTI. Voided volume (VV) and post-void residual urine (PVR) were measured by weighting diaper and suprapubic ultrasound after finishing voiding, respectively. Average PVR was defined as the mean value of PVR during 4-H observation. Interrupted voiding was defined as two or three voidings within 10 min. Voiding efficiency was defined as VV/(VV + PVR).ResultsThe mean ages of Group 1 (n = 64) and Group 2 infants (n = 56) were 10.6 ± 7.5 months vs 10.2 ± 5.1 months, respectively (p = 0.70). Group 1 infants had significantly higher voiding frequency (3.0times ± 1.2 vs 2.6times ± 0.9, p = 0.04), average PVR (14.5 ml ± 14.2 vs 8.9 ml ± 8.8, p < 0.01) and lower voiding efficiency (71.2% ± 20.5 vs 80.2% ± 18.5, p = 0.01) than Group 2. ROC curve analysis showed that the optimal cutoff values for PVR and voiding efficiency to differentiate Group 1 and Group 2 infants were 10 ml and 80%, respectively. Group 1 infants had significantly more repeat elevated PVR (≧ 10 ml) and repeat low voiding efficiency (≦ 80%) than Group 2 (44.8% vs 22.4%, p = 0.03; 62.0% vs 28.6%, p < 0.01, respectively).ConclusionPre-toilet trained infants with f-UTI were associated with elevated PVR and lower voiding efficiency than normal controls.