Pyelonephritis, renal scarring, and reflux nephropathy: a pediatric urologist's perspective.

Imaging of children with a clinical diagnosis of pyelonephritis is performed to characterize the extent of the infection, to identify associated renal injury and to uncover risk factors for future infections and renal damage. Although there is general agreement regarding the need for parenchymal imaging and the need to exclude processes that are either functionally or anatomically obstructive, there is controversy regarding the need for routine cystography, especially when parenchymal involvement has not been documented. A protocol that limits the use of cystography for evaluation of urinary tract infections must assume that the diagnosis of reflux is at least of variable clinical significance. It is now clear that vesicoureteral reflux and reflux nephropathy represent a diverse population that includes both congenital and acquired processes. MR imaging will improve our understanding of vesicoureteral reflux, pyelonephritis and renal scarring and might help us to identify and manage those patients most at risk for recurrent infections and renal injury. To recognize the potential contributions of this newer imaging technique it is helpful to look at our understanding of the pathophysiology of pyelonephritis, reflux and reflux nephropathy.