Clinical Predictors for Abnormal Renal Bladder Ultrasound in Hospitalized Young Children with a First Febrile Urinary Tract Infection

BACKGROUND: Physicians often obtain a routine renal bladder ultrasound (RBUS) for young children with a first febrile urinary tract infection (UTI). However, few children are diagnosed with serious anatomic anomalies, and opportunity may exist to take a focused approach to ultrasonography. We aimed to identify characteristics of the child, prenatal ultrasound (PNUS), and illness that could be used to predict an abnormal RBUS and measure the impact of RBUS on management. METHODS: We conducted a single-center prospective cohort study of hospitalized children 0 to 24 months of age with a first febrile UTI from October 1, 2016, to December 23, 2018. Independent variables included characteristics of the child, PNUS, and illness. The primary outcome, abnormal RBUS, was defined through consensus of a multidisciplinary team on the severity of ultrasound findings important to identify during a first UTI. RESULTS: A total of 211 children were included; the median age was 1.0 month (interquartile range 0-2), and 55% were uncircumcised boys. All mothers had a PNUS with 10% being abnormal. Escherichia coli was the pathogen in 85% of UTIs, 20% (n 5 39 of 197) had bacteremia, and 7% required intensive care. Abnormal RBUS was found in 36% (n 5 76 of 211) of children; of these, 47% (n 5 36 of 76) had moderately severe findings and 53% (n 5 40 of 76) had severe findings. No significant difference in clinical characteristics was seen among children with and without an abnormal RBUS. One child had Foley catheter placement, and 33% received voiding cystourethrograms, 15% antibiotic prophylaxis, and 16% subspecialty referrals. CONCLUSIONS: No clinical predictors were identified to support a focused approach to RBUS examinations. Future studies should investigate the optimal timing for RBUS.