Hydronephrosis may lead to uremia. Narrowing of the lumen of the urinary tract anywhere from the kidney to the external urethral orifice and obstruction of the urinary tract can cause urine to accumulate in the kidney, leading to dilatation of the renal pelvis and renal calyces, which is called hydronephrosis. If the obstruction is not relieved in time, urine retention in the renal pelvis increases the pressure in the renal pelvis, dilates the renal pelvis and renal calyces, and even leads to renal parenchyma atrophy and reduced blood flow, and the condition develops for a long period of time, obstructive nephropathy can be formed. In the long run, and the condition is not well controlled, renal failure can occur, and then progress to uremia. If patients find hydronephrosis, it is recommended to go to regular hospitals in time, and standardize the treatment under the guidance of doctors.