Prevalence of upper urinary tract anomalies in hospitalized premature infants with urinary tract infection

OBJECTIVE: The 2011 American Academy of Pediatrics (AAP) guidelines address imaging after initial febrile urinary tract infection (UTI) in infants 42 months of age. We sought to determine the frequency of upper urinary tract anomalies (hydronephrosis and vesicoureteral reflux (VUR)) in hospitalized premature infants with UTI. STUDY DESIGN: We retrospectively reviewed the electronic medical records of neonatal intensive care unit (NICU) admissions at a tertiary care children's hospital between 1 January 2006 and 31 December 2010. We queried the records for UTI, renal ultrasound (US) and voiding cystourethrogram (VCUG). RESULT: We identified 3518 unique admissions. UTI occurred in 118 infants (3%). Sixty-nine (60%) had a normal US. Renal dilation was predominantly renal pelvic dilation (12%) and isolated caliectasis (22%). VUR was identified in 15 (14%) infants evaluated with a VCUG. VUR was identified in nine (12%) infants without and in seven (16%) with an abnormality on US. Reflux was identified in 7% of male and 38% of female infants with a UTI. CONCLUSION: Anatomic abnormalities of the upper urinary tract are uncommon in premature infants with a UTI that occurs during neonatal hospitalization. In concordance with the AAP guidelines, a VCUG may not be required in all NICU infants under age 2 months after a single UTI.