Urinary tract infection in the neonates: what radiologic investigations should we do?

Introduction: Urinary tract infection (UTI) is the most common bacterial infection in febrile newborns. The exact prevalence is difficult to determine.

Aim: To determine if renal ultrasound is sufficient in newborns diagnosed with urinary tract infection (UTI) or if they require a routine voiding cystourethrogram.

Methods: Retrospective data analysis for infants admitted in the neonatal department in Mongi Slim Hospital in Tunis between January 2007 and December 2016 and diagnosed with UTI in the first month of life.

Results: 75 newborns were diagnosed with the first episode of UTI during their hospitalization. The median age was 15 days; there were 52 (70%) males. Fetal ultrasound data were available for 70 patients (90%), of whom 14 (20%) had abnormal findings. E.coli was the most common causative pathogen founding 62 patients (83%). Renal ultrasound was performed in all patients, of which 20 (27%) were reported as abnormal. VCUG results were available for 32 infants (43%), of which 11 (34%) were interpreted as abnormal; Eight of them (73%) demonstrated vesicoureteric reflux (VUR).Comparison of the patients with and without malformative uropathy in our study, concluded that there was no significant difference in age, gender, urine culture specimen and positivity of blood culture. However antenatal ultrasound abnormalities were predictive of vesicoureteric reflux and other renal abnormalities (p = 0.001). The sensitivity of renal ultrasound for detection of vesicoureteric reflux and other renal or ureteral abnormalities was 81.8 %, specificity was 81 %. The positive predictive value (VPP) was 69.2 % and the negative predictive value was 89.5 %.

Conclusion: In infants presenting with UTI in the first month of life, conservative follow-up with renal ultrasound examination and early detection of recurrent UTI are sufficient.