Glomerulosclerosis in obstructive uropathy

Obstructive uropathy is said to result in populations of remnant nephrons subject to hyperfiltration. We studied all obstructed renal tissue removed at our pediatric institution during a 10-year period for focal segmental glomerulosclerosis, which is the histological hallmark of hyperfiltration. Over-all, the histological specimens from 20 patients with ureteropelvic junction obstruction, 14 who underwent heminephrectomy for duplication anomalies and 5 with posterior urethral valves who underwent native nephrectomy were studied. Focal segmental glomerulosclerosis was one of the most common histological findings in these obstructed kidneys but it almost always was found in association with intense interstitial and periglomerular inflammation. We conclude that although focal segmental glomerulosclerosis is common in obstructive uropathological conditions it results from the inflammatory response within the renal parenchyma and not from the hyperfiltration of remnant nephron populations.