Background: "Fetal" vesicoureteral reflux (VUR) is characterized by predominance among males, high grade reflux and renal parenchymal abnormalities, indicating an association between sterile VUR and kidney lesions.
Objectives: To determine, using technetium99m-dimercaptosuccinic acid (99mTc-DMSA) renal scan, the incidence of congenital renal abnormalities in infants with sterile VUR detected during the postnatal evaluation of prenatal hydronephrosis or sibling reflux screening and to speculate on the mechanisms of these lesions.
Methods: We retrospectively reviewed the DMSA renal scans of infants with VUR without a history of urinary tract infection (UTI). DMSA differential uptake less than or equal to 40% or cortical defects were considered as renal abnormalities. The findings were correlated with those of postnatal renal ultrasonography.
Results: Eighteen patients (15 boys and 3 girls) were included with VUR grade V, IV, III and II in 5, 10, 6 and 6, respectively, of the 36 renal units. DMSA revealed parenchymal abnormalities in 50% (9/18) of the patients and in 33% (9/27) of the renal units with VUR; most of the patients were boys (7 boys, 2 girls) with VUR grade V or IV (6/9; 66%). Postnatal ultrasonography showed low sensitivity (22%) to renal injury.
Conclusions: In infants with sterile VUR, especially boys with high grade VUR, kidney abnormalities can already be present at birth suggesting a pathophysiology of renal injury independent of UTI. Moreover, renal parenchymal defects detected by DMSA renal scan are frequently not identified by postnatal renal ultrasound. Therefore, we recommend DMSA scanning in the initial evaluation of infants with VUR.