Unilateral Hydronephrosis Affecting the Contralateral Kidney and Ureter

In the 3 cases presented, unilateral hydronephrosis and/or hydroureter extend across the midline to affect the contralateral excretory system. In 2 cases the affected kidney was enlarged and displaced with resultant hydronephrosis of the contralateral side. In the third case, a left ureteral calculus was observed on the right side of the spine. It is emphasized that unilateral management of the diseased urinary tract may result in improvement on the contralateral side.