Severe hydronephrosis may cause kidney atrophy. The symptoms of the patient can be divided into two aspects: Firstly, hydronephrosis may cause some clinical symptoms, such as some patients may experience swelling in the lumbar and back area, and a decrease in urine output. Patients may suffer from spasms of the ureter due to obstruction of the urinary system, resulting in severe pain, and some patients may also have hematuria. On the other hand, the atrophy of kidney tissue caused by this hydronephrosis actually means the loss of kidney function. Patients may exhibit symptoms of renal failure, such as swelling of limbs, increased blood pressure, nausea, vomiting, loss of appetite, anemia, and other clinical symptoms.