PEDIATRIC UROLOGY

Imaging studies after a first febrile urinary tract infection in young children
Hoberman A, Charron M, Hickey RW, Baskin M, Kearney DH, Wald ER
Department of Pediatrics, University of Pittsburgh School of Medicine and Children’s Hospital of Pittsburgh, Pittsburgh, 15213-2583, USA
N Engl J Med. 2003; 348:251-2

• Background: Guidelines from the American Academy of Pediatrics recommend obtaining a voiding cystourethrogram and a renal ultrasonogram for young children after a first urinary tract infection; renal scanning with technetium-99m-labeled dimercaptosuccinic acid has also been endorsed by other authorities. We investigated whether imaging studies altered management or improved outcomes in young children with a first febrile urinary tract infection.
• Methods: In a prospective trial involving 309 children (1 to 24 months old), an ultrasonogram and an initial renal scan were obtained within 72 hours after diagnosis, contrast voiding cystourethrography was performed one month later, and renal scanning was repeated six months later.
  Results: The ultrasonographic results were normal in 88 percent of the children (272 of 309); the identified abnormalities did not modify management. Acute pyelonephritis was diagnosed in 61 percent of the children (190 of 309). Thirty-nine percent of the children who underwent cystourethrography (117 of 302) had vesicoureteral reflux; 96 percent of these children (112 of 117) had grade I, II, or III vesicoureteral reflux. Repeated scans were obtained for 89 percent of the children (275 of 309); renal scarring was noted in 9.5 percent of these children (26 of 275).
• Conclusions: An ultrasonogram performed at the time of acute illness is of limited value. A voiding cystourethrogram for the identification of reflux is useful only if antimicrobial prophylaxis is effective in reducing reinfections and renal scarring. Renal scans obtained at presentation identify children with acute pyelonephritis, and scans obtained six months later identify those with renal scarring. The routine performance of urinalysis, urine culture, or both during subsequent febrile illnesses in all children with a previous febrile urinary tract infection will probably obviate the need to obtain either early or late scans.
  
• Editorial Comment
  This is a fascinating study that tests our acceptance of routine radiographic testing in children with febrile urinary tract infections. By performing a renal ultrasound, VCUG and DMSA scan in all febrile infants with a UTI and then looking back at the results, the authors concluded that the ultrasound played no role in management. Furthermore, the DMSA scan did not alter management either. Although the authors still accept a role for the VCUG, they challenge the reader to prove the assumption that prophylactic antibiotics will reduce the incidence of reinfection and renal scarring. Although further studies of this population group are needed, this study is important in that it is the first to provide evidence evaluating the effect of currently routine interventions in this population.

Dr. Barry A. Kogan
Chief and Professor of Urology and Pediatrics
Albany Medical College
Albany, New York, USA