Renal Ultrasound for Infants Younger Than 2 Months with a Febrile Urinary Tract Infection

Mahmuda Monowara; Afsana Habib; Alomgir Ahmed; Mahbub Hossain; Abu Ishaque Khan

Volume : VIII, Issue : I, January - 2019

Renal Ultrasound for Infants Younger Than 2 Months with a Febrile Urinary Tract Infection

Mahmuda Monowara, Afsana Habib, Alomgir Ahmed, Mahbub Hossain, Abu Ishaque Khan

Abstract :

OBJECTIVE. The aim of this study is to determine the performance of renal ultrasound for detecting vesicoureteral reflux (VUR) and obstructive uropathies in infants younger than 2 months with a feile urinary tract infection (UTI). MATERIALS AND METHODS. We performed a retrospective cohort study of infants younger than 2 months with fever and culture–proven UTI presenting from July 1, 2015, through December 31, 2017, with renal ultrasound and voiding cystourethrogram (VCUG) performed within 30 days of UTI diagnosis.A single radiologist independently reviewed the renal ultrasound and VCUG findings. Results of the renal ultrasound were deemed abnormal if collecting system dilation, renal size asymmetry, collecting system duplication, urothelial thickening, ureteral dilation, or bladder anomalies were present. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of renal ultrasound were calculated using VCUG as reference standard. RESULTS. Of the 208 patients included (mean [SD] age, 31.8[13] days; male–to–female ratio, 3:1, 25% (n = 54) had VUR grades I–V, with 16% (n = 35) having VUR grades III–V and 8% (n = 18) having VUR grades IV–V. For grades I–V VUR, sensitivity was 32.5% (95% CI, 20.0–47.5%), specificity was 69.5% (95% CI, 61.5–76.9%), PPV was 26.1% (95% CI, 15.8–39.1%), and NPV was 75.7% (95% CI, 67.6–82.7%). No obstructive uropathies were diagnosed by VCUG in patients with normal renal ultrasound findings. CONCLUSION. In infants younger than 2 months, a normal renal ultrasound makes the presence of grades IV and V VUR highly unlikely but does not rule out lower grades of VUR.