The Clinical Significance of Intrarenal Reflux in Voiding Cystourethrography (VCUG)

Purpose Intrarenal reflux (IRR) occurs in 3-10% of cases of total reflux and can lead to renal injury, which may eventually result in renal scarring. In this study, we evaluated the clinical importance of IRR detected by voiding cystourethrography and evaluated the relationship between IRR and renal scarring. Materials and Methods From January 2002 to May 2008, 50 patients who were diagnosed with vesicoureteral reflux (VUR) and showed IRR in voiding cystourethrography were enrolled. IRR was seen in 59 renal units in our enrolled patients. A 99mTc 2,3-dimercaptosuccinic acid (DMSA) renal scan was performed after VUR was detected in all cases. Nine patients were conservatively treated with prophylactic antibiotics, whereas 41 patients received an anti-reflux operation. A follow-up renal scan was performed after 3 to 6 months to check for any changes in renal scarring. Results The average patient age was 9.2 months (range, 1-42 months). Forty-nine patients were male; only one patient was female. The mean duration until surgery was 2.9 months. Generally, the IRR sites corresponded to the sites of photon defects on DMSA renal scans (76.3%). Furthermore, the photon defects on IRR sites tended to progress to renal scarring (65.2%). The rate of change in scarring was lower in the surgery group (47.1%) than in the prophylactic antibiotic group (75%). Conclusions IRR sites and the sites of photon defects on DMSA renal scans showed a high correspondence, and these sites tended to progress to renal scarring. We suggest that VUR with IRR should be actively managed to decrease the chances of renal scarring.