Technetium-99m-DMSA studies in pediatric urinary infection

Abstract

Urinary tract infection (UTI) is a common condition in children and may lead to renal scarring with a risk of later hypertension and renal insufficiency. We made a cross-sectional study of the 99mTc-DMSA findings in 496 children referred for following symptomatic UTI to a Department of Nuclear Medicine and we categorized the results, to provide a framework for further study.

Method: A standard 99mTc-DMSA protocol was used to study 496 children (157 males, 339 females) aged from birth to 14 yr. Findings were classified according to the image appearance and relative function of each kidney. These were related to age, sex, history and timing of UTI and the results on micturating cysto-urethrography (MCU).

Results: Images were normal, with function within limits (45%-50% in one kidney), in approximately half the boys and girls studied. The other images were classified as equivocal in 68 children, abnormal unilaterally in 105 and bilaterally in 76, and they were subdivided according to the image appearance. No image changes could be identified that were specifically associated with acute UTI. Diffuse change alone was uncommon. A high proportion of abnormal images was found in infant boys, older girls with recurrent UTI and those children with vesico-ureteric reflux (VUR). Of the bilateral abnormal images, 98% were seen in children with VUR.

Conclusion: Our findings suggest that infective renal change may be superimposed on underlying congenital lesions (perhaps detectable antenatally) or may be acquired following UTI in the presence of reflux and are thus potentially preventable. This study also suggests that VUR is almost certain to have occurred in a child who has bilateral abnormal 99mTc-DMSA images following UTI and is also commonly present in those with definite unilateral defects.