Urinary tract infection: Is there a need for routine renal ultrasonography?
Article Outline
Zamir G, Sakran W, Horowitz Y, Koren A, Miron D. Arch Dis Child 2004;89:466-8
Context The American Academy of Pediatrics has recommended a combination of ultrasound, contrast, or isotope cystography for children up to the age of 2 years with a febrile UTI.
Objective To assess the yield of routine renal ultrasound (RUS) in the management of young children hospitalized with first uncomplicated febrile urinary tract infection (UTI).
Design Prospective cohort.
Setting Medium-sized regional medical center in Israel.
Participants All children aged 0 to 5 years who had been hospitalized over a two-year period with first uncomplicated febrile UTI. Children with known urinary abnormalities and/or who had been treated with antibacterial agents within 7 days before admission were excluded.
Interventions All included children underwent renal ultrasonography during hospitalization and voiding cystouretrography (VCUG) within 2 to 6 months
Main outcome measures The yield of RUS was measured by its ability to detect renal abnormalities, its sensitivity and specificity for detecting vesicoureteral reflux (VUR), and by its impact on UTI management.
Results Of 255 children that were included in the study, 33 children had mild-to-moderate renal pelvis dilatation on RUS suggesting VUR, of whom only 9 had VUR on VCUG. On the other hand, in 36 children with VUR on VCUG the RUS was normal. The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of abnormal RUS for detecting VUR were 17.7%, 87.6%, 1.43, and 0.94 respectively. In none of the patients with abnormal RUS was a change in the management at or after hospitalization needed.
Conclusion Results show that the yield of RUS to the management of children with first uncomplicated UTI is questionable.
Comment In the light of the increasing use of prenatal US, Zamir and colleagues have tested the value of routine diagnostic imaging and specifically questioned whether US is necessary. In this well-done, prospective assessment, abnormalities on US were found in 14.1% of patients, but in none did this influence management. VCUG revealed VUR in 47 (18.4%) patients, grades 1 to 3 in all but one patient. No scintigraphy was carried out. This report and a similar one published last year1 confirm the previously recognized low sensitivity of US for VUR. Both studies involved infants and young children with febrile UTI, and whether the same recommendations would apply to the older child remains an open question. Zamir and colleagues suggest that in the patient who has a normal late prenatal US, further US should be limited to those who have a complicated course, and VCUG should be used as the sole screening test. However, apart from the invasive nature of VCUG and the reluctance of many radiologists to undertake this study beyond infancy, this protocol is predicated on the unproven assumption of the value of prophylaxis in patients with VUR. In addition, VUR is of low-grade in the majority of patients and associated with a low risk of parenchymal scarring. One must exercise some caution before dispensing with US in the child with uncomplicated UTI. Prenatal anomaly scanning is by no means universal in many countries, and for maximum sensitivity for the detection of a dilated fetal urinary tract the scan would have to be carried at ≥20 weeks' gestation. In addition, one would have to ensure that other important aspects of the evaluation, particularly simple preventive advice, are not lost merely because imaging may be considered unnecessary. Finally, the debate on imaging has to a significant extent diverted attention from the importance of early and accurate diagnosis and treatment and care must be taken to avoid minimizing this aspect of management.
Reference
PII: S0022-3476(04)00757-7
doi:10.1016/j.jpeds.2004.08.038
© 2004 Elsevier Inc. All rights reserved.
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