[Imaging strategy for children after a first episode of pyelonephritis].

Pyelonephritis is a common bacterial disease in young children and is a serious infection because of its potential to produce renal scarring. One of the concerns of physicians is therefore the diagnosis of uropathy at risk for recurrence of pyelonephritis, especially high-grade reflux. There are no French recommendations on imaging evaluation after a first episode of pyelonephritis. Voiding cystography was systematically proposed years ago and recommended by the American Academy of Pediatrics until 1999. This systematic strategy exposed all children to a painful, irradiating exam, and exposed them to urinary tract infection. The American recommendations changed in 2011 and cystography is now only proposed to children with recurrence of pyelonephritis or with ultrasound abnormalities. A collaborative review of the literature involving the Pediatric Emergency, Nephrology and Surgery Departments at Necker-Enfants-Malades Hospital led us to propose an algorithm for imaging after the first episode of pyelonephritis in children. This algorithm was based on data from the past medical history (results of prenatal ultrasonography or recurrence of pyelonephritis), the results of the ultrasound exam at the time of diagnosis, and the procalcitonin concentration, to limit the indications for voiding cystography, limiting risk for delaying high-grade reflux diagnosis. Children with low risk for high-grade reflux can be followed up with an ultrasound exam 6 months after acute infection.