352 Febrile Urinary Tract Infection in Infants. Is Cystourethrography Necessary?

Abstract

Background and aims: To investigate infants after a febrile urinary tract infection with imaging studies is a common practice. Recently, the tendency is to avoid doing a cystourethrography in this group of risk although vesicoureteral reflux is associated with recurrent UTI and renal scars. Objetive: To evaluate the efficacy of combined DMSA scan and renal ultrasound to predict VUR in infants after a first febrile UTI. Methods: This prospective study includes 295 infants less than 2 years, 114 males (38'6%) and 181 females (61'4%). A renal US and a DMSA scan were performed after diagnosis, and a voiding cistourethrography 4 weeks later. We assessed sensibility, specificity, positive and negative predictive value, and estimated the odds ratio. Results: Vesicoureteral reflux was diagnosed in 82 infants (27'7%). 64 of them were low grade (I, II) and 18 were high grade (III, IV, V). In those with low grade, 25% showed abnormal findings in renal US, and 57% in DMSA scan. In those with high grade, 78% showed pathological US, and 69,6% abnormal DMSA scan. Combining both studies, 86'9% of high grade VUR but only 64'4% of low grade VUR showed pathological findings. The odds ratio for high grade reflux was 3'68 (95% CI 0'98-13'87). Conclusions: In infants presenting with a first febrile UTI, renal US and DMSA scan must be performed during acute illness. Cystourethrography would then be indicated when renal US, DMSA scan or both were pathological. However, the value of these imaging studies for predicting low grade reflux is limited.