HDCN Article Review/Hyperlink

Benador D, Benador N, Slosman D, Mermillod B, Girardin E

Are younger children at higher risk of renal sequelae after pyelonephritis ?

Lancet (Jan) 349:17-19 1997

Traditional teaching about UTIs, vesicoureteral reflux, and renal scarring in children has been that since new scars are uncommon in children > 5 years old with UTI, it is not necessary to be as aggressive in imaging or giving antimicrobial prophylaxis to these older children as it is with infants and younger children (see the December 1995 review by Hellerstein in Pediatric Clinics of North America). The authors of this report take issue with this traditional teaching.

Two hundred and one children admitted for management of pyelonephritis were prospectively entered into this study. All children underwent renal ultrasonography and DMSA scanning at the time of their infection, followed by a VCUG 6 weeks later, and if the first DMSA scan was abnormal, a second scan was obtained an average of 3 months later. For analysis purposes, children were grouped by age and by whether this was their first or a recurrent infection.

RESULTS & CONCLUSIONS: Abnormal initial DMSA scans, suggesting parenchymal involvement, were found in 55% of children aged <1, 79% of children aged 1-5, and 69% of children aged > 5. For children with their first infection, the percentages were 58%, 82% and 55%, respectively. Repeat DMSA scanning was abnormal in 60% of children with abnormal initial scans; however, the lesions had partially regressed in 60% of this group, leaving 23% of the original group with persistent lesions that were identical to the lesions seen on their first scan (yes, the numbers are somewhat hard to follow). 35% of the children with parenchymal involvement on their initial DMSA scan had reflux demonstrated on their VCUG, but only 22% had both reflux and scarring. From these data, the authors conclude that the development of renal scarring is NOT correlated with the age at which children present with urinary infection and therefore all children are at risk for development of scarring with infection.

Comment: DMSA scanning is a new technique that is highly sensitive for parenchymal renal involvement during an episode of pyelonephritis; however, these acute changes can take quite some time to resolve, so most authors recommend a waiting period of 6-12 months after an episode of infection before re-scanning a patient for the development of "scars." Therefore the authors of this paper may have over-estimated the incidence of permanent scarring by not waiting long enough to obtain the second scan. The high incidence of parenchymal involvement during episodes of urinary infection reported in this study highlights the usefulness of DMSA scanning in confirming the diagnosis of pyelonephritis in patients of all ages. (Joseph T. Flynn, M.D., University of Michigan)