The authors of the report in the December issue of Pediatrics issued online November 8 point out that the risk of renal scarring in children with a UTI has not been systematically studied. To review the prevalence of acute and chronic renal imaging abnormalities in this setting, the researchers identified 33 relevant studies that met their inclusion criteria.
The studies included a total of 4891 children. “Twenty studies were conducted in Europe, where most boys are uncircumcised, which may explain the relatively high proportion of boys in these studies,” Dr. Nader Shaikh and colleagues at Children’s Hospital of Pittsburgh, Pennsylvania note.
A meta-analysis of the pooled data showed that 57% of the children with an initial UTI had evidence of acute pyelonephritis on DMSA scans. “Studies with a higher proportion of male subjects reported lower rates of early DMSA scan abnormalities,” the investigators found. Also, children with vesicoureteral reflux were 1.5 times more likely than those without to have acute pyelonephritis.
The prevalence of renal scarring 5-24 months after an initial UTI varied considerably with the year of publication of the study, with recent studies reporting a lower prevalence. “Results of cumulative meta-analysis suggested that rates have been relatively stable at 15% since 2002,” according to the report.
Furthermore, the team found, the prevalence of renal scarring was 2.6 times higher among children with vesicoureteral reflux than those without.
In discussing the results, Dr. Shaikh and colleagues review which tests, if any, should be used routinely in children with UTIs.
The yield of ultrasonography is likely to be low, they advise, but voiding cystourethrograms are expensive, invasive “and miss a significant proportion of children who are at risk for renal scarring.” On the other hand, DMSA scans can identify most children who are likely to scar, but the tests are also invasive and expose children to radiation.
Nonetheless, the authors conclude, “The pooled prevalence values provided from this study provide a basis for an evidence-based approach to the management of children with this frequently occurring condition.”
Risk of Renal Scarring in Children With a First Urinary Tract Infection: A Systematic Review