Hydronephrosis is a common disease in urology. The causes of hydronephrosis are diverse, and the symptoms of hydronephrosis are also different. They can be roughly divided into the following categories. First of all, abdominal pain, which is often the first symptom of patients with hydronephrosis, may manifest as chronic vague and dull pain, or severe acute renal colic. The site of pain may be in the lumbar region, or in the kidney region of the lumbar region, or even in the groin region. Second: Gastrointestinal symptoms. Hydrocele can cause smooth muscle spasm in the upper urinary tract ducts, which reflexively causes gastrointestinal discomfort, including abdominal pain and bloating, and even nausea and vomiting. The degree of gastrointestinal symptoms is not proportional to the degree of hydronephrosis. In addition, there are also symptoms such as hematuria, urinary tract infection, swelling, and even infection-related symptoms such as fever and chills. Long-term bilateral hydronephrosis may even eventually lead to renal failure and manifestations related to renal failure. It should be noted that clinically, a significant proportion of hydronephrosis may not have obvious symptoms, and the degree of hydronephrosis is not proportional to the symptoms.