Utility of screening ultrasound after first febrile UTI among patients with clinically significant vesicoureteral reflux

Objective: To assess the sensitivity and negative predictive value (NPV) of screening renal and bladder ultrasound (RBUS) after initial febrile urinary tract infection (UTI) among patients with clinically significant vesicoureteral reflux (VUR).

Methods: A retrospective review was performed of all children <2 years of age who presented with a febrile UTI between 2004 and 2011. The sensitivity and NPV of initial RBUS was calculated among patients who were found to have high-grade (IV-V) VUR. Additionally, initial RBUS among patients with evidence of photopenia on dimercaptosuccinic acid (DMSA) scan or who underwent surgical intervention were reviewed.

Results: One hundred forty-four patients with febrile UTI were identified; available RBUS, voiding cystourethrogram (VCUG), and DMSA results for each kidney were reviewed. One hundred fifty-eight kidneys had evidence of VUR on VCUG, and initial RBUS demonstrated abnormality in 25 (sensitivity 0.17). Forty-five kidneys had high-grade VUR and RBUS revealed abnormality in 16 (sensitivity 0.36). One hundred seventy-eight kidneys had no evidence of abnormality on initial RBUS, and 136 (76%) were found to have VUR (NPV 0.24), of which 31 had high-grade VUR (NPV 0.83). Seven kidneys had scarring on DMSA and initial RBUS was normal in 4 (57%). Twelve of 19 patients (63%) who eventually underwent surgical intervention had a normal initial RBUS.

Conclusion: RBUS has poor sensitivity and NPV for detecting high-grade VUR in patients <2 years who present with a febrile UTI. A significant number of patients who were diagnosed with high-grade VUR, renal scarring, or underwent surgical correction of VUR had a negative screening RBUS.