Correspondence
Imaging Studies after a First Febrile Urinary Tract Infection in Young Children
N Engl J Med 2003; 348:1812-1814May 1, 2003
- Article
To the Editor:
Hoberman et al. (Jan. 16 issue)1 attribute the small effect of renal ultrasonography in the clinical management of febrile urinary tract infections to the widespread use of prenatal ultrasonography. However, reports and images from intrauterine ultrasonography are often unavailable, and the risk of missing a clinically significant obstructive lesion, given a history of normal prenatal ultrasonographic findings, has not been determined.2
For example, obstruction of the ureteropelvic junction is commonly diagnosed prenatally. However, in the era before ultrasonography, 27 percent of patients with such obstructions presented with a urinary tract infection,3 and the disorder might be missed without routine renal ultrasonography. The frequency of renal calculus is increasing among children,4 and patients with this condition may present with a urinary tract infection. The diagnosis is commonly made by ultrasonography, which leads to further evaluation. Given the noninvasive nature of ultrasonography and the possibility of identifying a potentially correctable underlying cause of infection, I believe that renal ultrasonography should continue to be part of the routine care of children with a first episode of febrile urinary tract infection.
4 ReferencesAkira Nishisaki, M.D.
Maimonides Medical Center, Brooklyn, NY 11219
akiranish@yahoo.com 1
Hoberman A ,Charron M ,Hickey RW ,Baskin M ,Kearney DH ,Wald ER . Imaging studies after a first febrile urinary tract infection in young children. N Engl J Med 2003;348:195-202
Full Text | Web of Science | Medline2
Auringer ST . Pediatric uroradiology update. Urol Clin North Am 1997;24:673-681
CrossRef | Web of Science | Medline3
Snyder HM III ,Lebowitz RL ,Colodny AH ,Bauer SB ,Retik AB . Ureteropelvic junction obstruction in children. Urol Clin North Am 1980;7:273-290
Web of Science | Medline4
Kroovand RL . Pediatric urolithiasis. Urol Clin North Am 1997;24:173-184
CrossRef | Web of Science | Medline
To the Editor:
The recommendation to focus imaging investigations on cystourethrography, when vesicoureteral reflux is seen in 39 percent of children, whereas renal damage is seen in 15 percent (38 percent of whom do not have vesicoureteral reflux), is difficult to follow. On the basis of 302 voiding cystourethrograms, 16 children were identified as having both vesicoureteral reflux and renal scarring. This finding suggests that the presence of vesicoureteral reflux does not identify a susceptible subgroup of children. Furthermore, no vesicoureteral reflux was demonstrated in 10 children with renal scarring. Thus, the possibility that a child has renal damage cannot be ruled out on the basis of the absence of vesicoureteral reflux. Indeed, a systematic review and meta-analysis by my colleagues and I1 failed to show a relation between vesicoureteral reflux and renal damage.
Since the complications of urinary tract infection are all related to renal damage, it seems illogical to recommend cystourethrography, an invasive test with a high burden of radiation, for children with a proven urinary tract infection. It would be more logical for the authors to recommend either no imaging (with which I would agree) or (if the clinician is unhappy about forgoing all imaging procedures) scanning with dimercaptosuccinic acid to identify renal scarring at six months. Such a strategy would focus on a potentially susceptible group of children who would require a voiding cystourethrogram.
1 ReferencesIsky Gordon, F.R.C.P.
Great Ormond Street Hospital for Children, London WC1N 3JH, United Kingdom
i.gordon@ich. ucl. ac. uk 1
Gordon I ,Barkovics M ,Pindoria S ,Cole TJ ,Woolf AS . Primary vesicoureteric reflux as a predictor of renal damage in children hospitalized with urinary tract infection: a systematic review and meta-analysis. J Am Soc Nephrol 2003;14:739-744
CrossRef | Web of Science | Medline
To the Editor:
How did the identification of children with reflux improve the outcome? If the purpose of antimicrobial prophylaxis is to prevent urinary tract infections and scarring, how many children had recurrent urinary tract infections? Since Hoberman et al. assume that reflux is a risk factor for pyelonephritis, how many of the 190 children with scintigraphically confirmed acute pyelonephritis had reflux, and how many with negative scintigraphic findings did?
The majority of children with urinary tract infections in the study by Hoberman et al. (61 percent) did not have reflux. In one prospective study, the likelihood of the eventual development of scars was independent of reflux status.1 Yet, in the study by Hoberman et al., only the children with reflux received antimicrobial prophylaxis. Do the authors assume that acute pyelonephritis without reflux is less inflammatory or that children without reflux are less prone than those with reflux to have a recurrence? Since scarring was not extensive, why recommend that voiding cystourethrography be performed in all young children with an initial febrile urinary tract infection and a normal ultrasonogram?
1 ReferencesRonald Kallen, M.D.
Children's Memorial Hospital, Chicago, IL 60614
r-kallen@northwestern.edu 1
Rushton HG ,Majd M ,Jantausch B ,Wiedermann BL ,Belman AB . Renal scarring following reflux and nonreflux pyelonephritis in children: evaluation with 99mtechnetium-dimercaptosuccinic acid scintigraphy. J Urol 1992;147:1327-1332[Erratum, J Urol 1992;148:898.]
Web of Science | Medline
Author/Editor Response
Performance of voiding cystourethrography in young children with a febrile urinary tract infection will identify those with vesicoureteral reflux who are candidates for antimicrobial prophylaxis. As we concluded in our article, voiding cystourethrography “is recommended under the so far unproven assumption that continuous prophylactic antimicrobial therapy is effective in reducing the incidence of reinfection and renal scarring.” We administered antimicrobial prophylaxis in children with reflux in general, regardless of their initial scintigraphic findings, because it represented the standard of care at all participating institutions. Imaging studies were conducted as part of a larger randomized clinical trial comparing outpatient therapy with inpatient therapy in children with a first febrile urinary tract infection.
Regarding Dr. Kallen's additional questions, the incidence of reinfection did not differ significantly between children with reflux and children without reflux (8 of 117 [6.8 percent] and 11 of 185 [5.9 percent], respectively; P=0.94). Similarly, the incidence of reflux did not differ significantly between children with scintigraphic evidence of acute pyelonephritis and children with normal scans (80 of 187 [43 percent] and 35 of 111 [32 percent], respectively; P=0.07). Although we agree that inflammation is present in children with acute pyelonephritis irrespective of the presence or absence of reflux, we are not aware of any controlled trials indicating the efficacy of antimicrobial prophylaxis to prevent renal scarring in children with acute pyelonephritis.
Dr. Gordon points out that voiding cystourethrography fails to identify a group of children who are susceptible to renal scarring. However, on the basis of our prospective data, reflux was the only covariate that was significantly associated with a higher likelihood of renal scarring; the long-term implications of this finding remain to be determined. We agree conceptually with Dr. Gordon's suggestion that no imaging may be necessary in children with a first febrile urinary tract infection. However, we must be persuaded by a properly designed placebo-controlled study that antimicrobial prophylaxis in children with reflux does not prevent renal scarring.
Although Dr. Nishisaki would like to continue performing routine ultrasonography in children with a first urinary tract infection in order to detect a potentially correctable underlying cause of infection, our data do not support this practice. Among the 309 prospectively evaluated children 24 months of age or younger with a first diagnosed febrile urinary tract infection, we failed to identify a single case of obstruction of the ureteropelvic junction requiring surgical intervention, and only 1 child had a calculus. However, if information regarding prenatal ultrasonography performed at an experienced center after 30 weeks of gestation is unavailable, or if the patient has a delayed response to treatment, consideration should be given to the performance of renal ultrasonography.
Alejandro Hoberman, M.D.
Robert W. Hickey, M.D.
Ellen R. Wald, M.D.
University of Pittsburgh School of Medicine, Pittsburgh, PA 15213-2583
hoberman@chp.edu - Citing Articles (2)
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