Imaging after urinary tract infection in older children and adolescents.

Abstract

PURPOSE: There are few guidelines and little data on imaging after urinary tract infections in older children. We determined the clinical yield of renal and bladder ultrasound, and voiding cystourethrogram in older children and adolescents after urinary tract infection. MATERIALS AND METHODS: We analyzed findings on voiding cystourethrogram, and renal and bladder ultrasound as well as the clinical history of patients who underwent the 2 studies on the same day between January 2006 and December 2010. We selected for study patients 5 to 18 years old who underwent imaging for urinary tract infection. Those with prior postnatal genitourinary imaging or prenatal hydronephrosis were excluded from analysis. RESULTS: We identified a cohort of 153 patients, of whom 74% were 5 to 8 years old, 21% were 8 to 12 years old and 5% were 12 to 18 years old. Of the patients 77% were female, 78% had a febrile urinary tract infection history and 55% had a history of recurrent urinary tract infections. Renal and bladder ultrasound findings revealed hydronephrosis in 7.8% of patients, ureteral dilatation in 3.9%, renal parenchymal findings in 20% and bladder findings in 12%. No patient had moderate or greater hydronephrosis. Voiding cystourethrogram showed vesicoureteral reflux in 34% of cases and bladder or urethral anomalies in 12%. Reflux was grade I, II-III and greater than III in 5.9%, 26% and 2% of patients, respectively. For any voiding cystourethrogram abnormality the sensitivity and specificity of any renal and bladder ultrasound abnormality were 0.49 (95% CI 0.37-0.62) and 0.76 (95% CI 0.66-0.84), respectively. Positive and negative predictive values were 0.58 (95% CI 0.44-0.71) and 0.69 (0.59-0.77), respectively. CONCLUSIONS: In older children with a history of urinary tract infection the imaging yield is significant. However, imaging revealed high grade hydronephrosis or high grade vesicoureteral reflux in few patients. Renal ultrasound is not reliable for predicting voiding cystourethrogram findings such as vesicoureteral reflux.