Source:Kass EJ, Kernen KM, Carey JM. Paediatric urinary tract infection and the necessity of complete urological imaging.
BJU Int.

Recent studies have demonstrated that many children with pyelonephritis or renal scarring after infection do not have vesicoureteral reflux (VUR) and that there is a low incidence of VUR in children with normal renal scans.1,2 These findings have led some to conclude that a child with a normal ultrasound or scintigraphy after a UTI does not require a VCUG.2 The authors studied the incidence of reflux in children who have normal upper tract studies following UTI. Four hundred sixty-eight children were evaluated for documented UTI from 1996–1998 at William Beaumont Hospital, Royal Oak, Michigan, and were reviewed retrospectively. One hundred one children who had both normal DMSA scans and renal ultrasounds constituted the study group and included 89 girls and 12 boys. VCUG revealed reflux in 23 (23%). Fifteen of 20 girls and all of the boys (3/3) who had VUR were age 5 years or younger, the age group generally accepted to be more susceptible to renal scarring from UTI. Of the 23, 9 had unilateral reflux and 14 had bilateral reflux. Interestingly, 13 (57%) had grade III or higher VUR. The goal of evaluating children with UTI is to diagnose any abnormality that may predispose the child to recurrent infection. Since 23% of children with normal upper tract studies had VUR, the authors conclude that children who have normal kidneys on ultrasound or renal scan still need a VCUG.

This is a retrospective study but it has the strength of large numbers of children evaluated in a consistent manner at a single institution in a relative short period of time. The authors do not give us information about the severity of the UTI or other patient history but instead chose to include all children with documented UTI. While some may argue that this is a wide net and that pyelonephritis is different than cystitis, it has been shown that clinical symptoms are unreliable in localizing the site of urinary infection.3 I would agree with the authors that urine culture documentation of UTI is the most reasonable indication for complete imaging of the urinary tract and that the modern radiographic VCUG offers the best initial imaging of the lower urinary tract. This study tells us that children with normal kidneys on the best available imaging studies following UTI frequently have significant vesicoureteral reflux. The knowledge that they have reflux should alter their subsequent care.

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