Renal Histopathological Changes in Children With Congenital Ureteropelvic Junction Obstruction.

Renal histologic changes in congenital ureteropelvic junction obstruction (UPJO), although well documented, are sparsely studied in children. This study aims to establish a histological grading depending on the glomerular and tubulo-interstitial changes in hydronephrotic kidneys and determine correlation with age at surgery and impact on function post-pyeloplasty. A renal cortical wedge biopsy was obtained after pyeloplasty and histological changes were graded from 1 to 4. A total of 47 viable biopsies from 57 children showed grade 1 changes in 10, grade 2 in 7, grade 3 in 27, and grade 4 in 3. Age at surgery, histological grade, and changes in differential renal function (DRF) were statistically analyzed. Younger age, near normal histology, and those with changes in 1 domain had preserved DRF pre-operatively. Renal histology and overall grade showed positive correlation with pre-operative DRF. However, no statistically significant association was noted with age at surgery or change in post-operative DRF.