Rational diagnostic steps in acute pyelonephritis with special reference to ultrasonography and computed tomography scan

Depending on the severity of the clinical syndrome, acute pyelonephritis ma y require more extensive imaging diagnostics. In the uncomplicated form of the disease, ultrasonography does not appear to be absolutely necessary. In clinically severe cases, however, which fail to respond to antibiotic ther apy, ultrasound is the optimal procedure for ruling out urinary tract obstr uction. Where there is clinical suspicion of complications-proven risk fact ors, persistent fever and/or continuing pathological inflammation parameter s (elevated C-reactive protein levels in serum)-ultrasonography is the prim ary imaging technique for the exclusion of pyonephrosis, as well as for oth er complicating factors such as calculi, etc. In cases of insufficient resp onse to antibiotic therapy, we recommend performing a renal computed tomogr aphy scan with contrast medium, in order to rule out hypoenhancing zones as hints for severe tissue alterations. This procedure is in accordance with the suggestions of the Society for Uroradiology. In the future, DMSA scinti graphy might constitute an equivalent diagnostic method for the exclusion o f these focal inflammatory changes. Above all, DMSA scintigraphy makes it p ossible to anticipate the development of scars following acute pyelonephrit is. (C) 1999 Elsevier Science B.V. All rights reserved.