DOES DELAYED OPERATION FOR PEDIATRIC URETEROPELVIC JUNCTION OBSTRUCTION CAUSE HISTOPATHOLOGICAL CHANGES

Purpose: We studied histopathological changes in kidneys with demonstr able ureteropelvic junction obstruction in relation to patient age, di fferential renal function and urinary tract infection. Materials and M ethods: Renal biopsy was performed in 42 children (44 kidneys) with a mean age of 3 years 6 months who underwent open pyeloplasty due to ure teropelvic junction obstruction. Each specimen was examined for revers ible inflammatory cell infiltration and irreversible change, including interstitial fibrosis, arteriolar thickening and glomerular sclerosis . Each pathological finding was scored 0 to 3 in increasing grades of severity, and correlated with patient age, differential renal function and history of urinary tract infection. Results: Of the 44 kidneys 20 (45%) had irreversible change. Correlation study revealed no associat ion between patient age and histological findings, and there was no st atistically significant difference in any histopathological category r egardless of age. Differential renal function correlated with inflamma tory cell infiltration and interstitial fibrosis. There were significa ntly worse histopathology scores in all categories when differential r enal function was less than 30 versus 40% or greater. Interstitial fib rosis was significantly worse in the 30 to 40% group than in the great er than 40% group. The histopathological score of interstitial fibrosi s was significantly higher in patients with than without urinary tract infection. Conclusions: Early correction in infants with ureteropelvi c junction obstruction may not be necessary when initial differential renal function is greater than 40%. However, any decrease in different ial renal function or recurrent urinary tract infections despite antib iotic prophylaxis warrant surgical correction of obstruction.