MP44-06 THE MODIFIED TOP DOWN APPROACH TO IMAGING: ANORMAL DMSA PREDICTS RECURRENT FEBRILE UTI RISK

INTRODUCTION AND OBJECTIVES: The goal of imaging after febrile UTI (FUTI) in children is to identify anatomic anomalies predisposing to recurrent FUTI and/or renal damage. Recommendations have varied from no imaging after 1st FUTI to renal/bladder ultrasound (RBUS) and VCUG in all patients. We used DMSA obtained 3 months after FUTI to evaluate baseline renal damage (Snodgrass et al, 2013) and determined rates of VUR and recurrent FUTI longitudinally. We present results of this modified “top-down” approach. METHODS: Beginning in 2008, consecutive children referred following FUTI underwent standardized evaluation and management. Imaging comprised RBUS, and DMSA 3 months after the last FUTI. Abnormal DMSA was defined as function <44% and/or cortical renal defect(s). VCUG was only done in those with abnormal DMSA if not obtained before referral. Patients with normal DMSA were observed without antibiotic prophylaxis regardless of VUR status, whereas those with abnormal DMSA had injection or reimplantation to resolve VUR, when present. Patients were followed at 6 month intervals until considered toilet-trained. Data was prospectively collected at time of service. RESULTS: There were 618 patients (79% female) referred after FUTI at median age 3.4 years. Of these, 149 (24%) had abnormal DMSA, in whom RBUS was normal in 66% and VUR was present in 76%. Follow up data was available in 602 children at mean of 1.7 years (5m-4y), with 119 (20%) developing recurrent FUTI. Risk factors for recurrent FUTI included abnormal DMSA (OR 2.5, 1.3-4.9), and 2 FUTI (OR 1.64, 1.3-2.1) before referral. Neither VUR nor VUR grade were independent risk factors for recurrent FUTI. Bowel/bladder dysfunction, diagnosed and managed in 61% of 505 toilet trained patients, also did not predict recurrent FUTI. CONCLUSIONS: Abnormal delayed DMSA occurred in 24% of referred children after FUTI, despite a normal RBUS in 66%. Abnormal DMSA was a risk factor for recurrent FUTI, as was recurrent FUTI before referral. Although VUR is a risk factor for abnormal DMSA, it did not predict recurrent FUTI during follow up despite no treatment in those with normal DMSA. Top down imaging using DMSA 3 months after last FUTI identifies patients with renal damage, and those at risk for recurrent FUTI. Cystography can be reserved for patients with abnormal DMSA or with recurrent UTI despite normal DMSA.