Procalcitonin and prediction of vesico-ureteral reflux in pediatric urinary tract infection

An estimated 7% of girls and 2% of boys will have a urinary tract infection before 6 years of age, and between 20 and 40% of these children are diagnosed with vesicoureteral reflux. Reflux is a risk factor for recurrent infections and renal scarring, which can lead to hypertension and kidney failure. Pediatric guidelines recommend routine voiding cystourethrography, but this is a painful and expensive examination that exposes children to radiation. Reliable non invasive markers of reflux would therefore be extremely useful. Ultrasonography and clinical decision rules have poor sensitivity for vesicoureteral reflux. In contrast, the level of procalcitonin, a marker of the severity of bacterial infections, is a good predictor of cystographic findings in children with a first febrile urinary tract infection. Indeed, a procalcitonin level below 0.5 ng/ml predicted the absence of radiological reflux with a sensitivity of more than 75% in the French princeps study. This was validated by a prospective European study, in which sensitivity reached 100% for high-grade reflux. Procalcitonin assay can thus avoid voiding cystourethrography in 40 to 50% of young children with febrile urinary tract infections.