1.The most common is infection, which can occur in the respiratory tract, digestive tract, skin, urinary system, etc. Respiratory tract infection: manifested as cough, sore throat, fever, etc. Blood tests are required. In severe cases, a chest X-ray is required. If the fever is low for a long time, tuberculosis needs to be investigated. Gastrointestinal tract infection: vomiting, abdominal pain, diarrhea, mucus and blood in stool, etc. Routine stool and blood tests are required. Skin infection: manifestation of skin redness, local pain, swelling, etc. Urinary system infection: manifestation of frequent urination, urgent urination, painful urination, fever, sometimes blood dripping after urination, etc., need to check urine routine and urine culture. Others: conjunctivitis, urethritis, etc. Preventive measures: oral care, urethral orifice care, hand washing, ventilation, dietary hygiene, keep the skin clean, pay attention to skin care at the nail groove. 2. Thrombosis When nephrotic syndrome is not in remission, it is in a hypercoagulable state and prone to thrombosis. This is a very serious comorbidity and can be life-threatening. Thrombosis can occur in the lungs, brain, renal veins, arteries and veins of the lower limbs, mesenteric vessels, etc. Pulmonary embolism: It is not uncommon and can manifest weakness, chest tightness, shortness of breath, cough, hemoptysis, and in severe cases, sudden death can be confirmed by CT examination of pulmonary artery. Cerebral embolism: it may show headache, vomiting, or even convulsion, and the diagnosis can be confirmed by cranial vascular examination. Renal vein thrombosis: It may show lumbar pain, hematuria, and bilateral kidneys of unequal size, which can be diagnosed by renal vascular ultrasonography or CT examination. Arterial thrombosis of lower extremity: manifesting pain in the extremity, numbness, coldness of the lesioned extremity, and impaired movement. Lower extremity venous thrombosis: manifesting swelling and protrusion of the affected limb. Mesenteric vascular embolism: manifesting abdominal pain, intractable ascites, etc. In severe cases, the intestinal wall is necrotic and peritonitis occurs. Preventive measures: anticoagulation treatment when nephrotic syndrome is not in remission, prevention of thrombosis, commonly used drugs: dipyridamole, heparin. When vomiting and diarrhea occur, timely rehydration and prevention of hemoconcentration. 3. Hypovolemic shock is a serious complication and life-threatening. It occurs when the nephrotic syndrome is not in remission, and when there is poor feeding, little water, vomiting and diarrhea. Performance: poor mental health, weakness, cold hands and feet, decreased or undetectable blood pressure. Preventive measures: ensure that the child has a basic amount of food and water, if vomiting and diarrhea occur, make up salt solution in time. 4, hypokalemia, hyponatremia, etc. Prevalent in poor feeding, vomiting and diarrhea. Performance: poor mental health, weakness, etc. Prevention: Ensure basic food intake and supplement salt solution when vomiting and diarrhea. 5.Acute renal insufficiency: Decrease in urine output, increase in blood pressure and increase in creatinine.