UROLOGICAL SURVEY   ( Download pdf )

 

PEDIATRIC UROLOGY

Abnormal dimercapto-succinic acid scans predict an increased risk of breakthrough infection in children with vesicoureteral reflux
Mingin GC, Nguyen HT, Baskin LS
Department of Urology and Pediatrics, University of California-San Francisco, San Francisco Children’s Hospital, San Francisco, CA, USA
J Urol. 2004; 172: 1075-7

  • Purpose: The management of high grade vesicoureteral reflux remains controversial, with breakthrough infections being an indication for surgical repair. We sought to determine if technetium dimercapto-succinic acid (DMSA) scan could help predict which children are at risk for breakthrough urinary tract infection.
  • Materials and Methods: A retrospective review was performed on children presenting with a febrile urinary tract infection and prenatal hydronephrosis who were found to have vesicoureteral reflux and underwent a DMSA scan. Reflux was tabulated according to the highest grade. DMSA results were graded as 0-normal, no parenchymal or size defects, grade 1-focal parenchymal defects or less than a quarter of a renal unit involved, or grade 2-severe defects to include at least half of a renal unit, bilateral defects or unilateral atrophy.
  • Results: A total of 120 consecutive patients were evaluated. An abnormal DMSA scan was documented in 57 (33 females and 24 males), and 35 with grade 1 and 22 with grade 2 defects. Of the patients 53 females and 10 males had a normal scan. Of the 57 children with an abnormal DMSA scan 6% presented with grades 1 and 2 vesicoureteral reflux, 24% with grade 3, 38% with grade 4 and 26% with grade 5. Of the children with grades 3 to 5 reflux 60% had a subsequent breakthrough infection. Of the 63 children with a normal DMSA scan 11% presented with grade 1 reflux, 28% with grade 2, 48% with grade 3, 11% with grade 4 and 2% with grade 5. Of these children 5 had a subsequent breakthrough infection.
  • Conclusions: An abnormality on DMSA scan in the presence of grade 3 to 5 reflux correlates with a greater chance of having a breakthrough infection (60%). We conclude that children with grade 3 to 5 vesicoureteral reflux and an abnormal DMSA scan are at increased risk for breakthrough urinary tract infection.

  • Editorial Comment
    It has been clearly demonstrated that DMSA scanning is a highly sensitive modality for detecting renal scarring. In particular, it has many advantages over renal ultrasound for this purpose. On the other hand, it is expensive and in terms of cost-effectiveness, the utility of DMSA scanning for determining renal injury in children with reflux has been questioned. In particular, it is important to determine whether the results of DMSA scanning alter management or outcome.
    This study looks at differences in outcome of children with reflux based on the results of DMSA scanning. Of 120 children evaluated, 57 had abnormal scans, including 33 girls and 24 boys. In contrast, of the 63 normal scans, only 10 were boys. Furthermore, in follow-up, 60% of those with an abnormal DMSA scan had a breakthrough UTI whereas only 8% of those with a normal DMSA had a breakthrough infection.
    The implications of these data are significant. First, as anticipated, boys with reflux have more renal injury, perhaps related to more abnormal neonatal voiding patterns with high intravesical pressures that are passed to the kidney. Second, those who already demonstrated a tendency to renal injury (because of either more abnormal voiding or a host resistance problem that results in a greater rate or more severe UTIs) are more likely to get further UTIs. Not only is this important in the pathophysiology of reflux and reflux nephropathy, but it suggests that more aggressive management of reflux in this population may be warranted. This in turn suggests value in obtaining a DMSA scan in children with grades 3-5 reflux.

Dr. Barry A. Kogan
Chief and Professor of Urology and Pediatrics
Albany Medical College
Albany, New York, USA