Observe vs repair. Most cases of hydronephrosis in children do not require treatment. In general, it is caused by either partial obstruction of the ureter or bladder, by reflux up the ureter from the bladder, or by large urine production. In many cases, it is none of the above. It is important to have an evaluation to understand its cause and to determine the best means of observing it for deterioration.
? How obstructed. Most cases of mild and many moderate hydronephrosis need no treatrment. Severe hydronephrosis in kids with high degree of outflow obstruction +/or reduced function with hyronephrosis require pyeloplasty surgery. Involves excising obstructing segment & rejoining ureter to kidney. Hydronephrosis due to high grade reflux or lower end ureteral obstruction may require uretero-vesicoplasty surgery.