For simple hydronephrosis, it does not cause the appearance of hematuria. If the hydrocele is secondary to urinary tract infection, the symptoms of hematuria may occur. It is mainly due to urinary tract infection, which can cause congestion and edema in the mucosa of the urethra, and there will be a large amount of leakage of red blood cells. There are also some specific causes of hydronephrosis, such as urinary stones that cause hydronephrosis, and stones can also cause hematuria or hydronephrosis due to foreign blood vessel entrapment, but the entrapment can cause the ureteral mucosa to also appear congested and edematous, which can also be accompanied by the appearance of hematuria, such as future tumors pressing on the ureter, which can cause hydronephrosis or the ureter itself to produce tumors and appear Hydronephrosis can also have tumors that grow too fast and cause internal bleeding and necrosis, which can lead to the appearance of hematuria. However, when there is hematuria, the patient should conduct a careful investigation to clarify the cause of hematuria.