Deep vein thrombosis (DVT) is a common clinical vascular surgical disease, and the fall and winter seasons are its most frequent. Deep vein thrombosis refers to the abnormal clotting of blood in the deep vein system, which is usually found in the lower limbs, mostly in postpartum, post-pelvic surgery, trauma and patients who are bedridden for a long time. The main manifestations are: swelling, weakness and pain of the affected limbs, and the feeling of heaviness of the limbs is obvious. If the disease is not treated in time, the thrombus can be dislodged and lead to pulmonary embolism, which can be life-threatening in serious cases, and young patients may lose their ability to work. Nevertheless, it is often ignored by patients and the best time for treatment is missed, mainly because people do not know enough about deep vein thrombosis. High blood viscosity, slow blood flow and damage of blood vessel wall are the three main causes of this disease, which mostly occurs in people who are bedridden after various surgeries, chronic diseases and limited limb activities due to various reasons. Clinical performance characteristics 1. Cardiogenic edema. It is mainly a manifestation of heart failure. The edema is characterized by appearing first in the sagging part of the body, and in those who can get up and move around, it first appears on the inner side of the ankle, is obvious after walking and moving around, and is reduced or disappears after rest. The face is generally not swollen. Edema is symmetrical and depressed. 2. Nephrogenic edema. It can be seen in all types of nephritis and nephropathy. The edema is characterized by eyelid and facial edema when waking up in the morning in the early stage of the disease, and later develops into generalized edema. 3. Hepatogenic edema. It is caused by decompensated cirrhosis, mainly manifested as ascites, and may first appear as ankle edema, gradually spreading upward, while the head, face and upper limbs often do not have edema. 4.Malnutrition edema. Chronic wasting disease, long-term nutritional deficiency, protein-losing gastrointestinal disease, hypoproteinemia due to severe burns, vitamin B1 deficiency, etc. can all produce edema. Tissue laxity and reduced tissue pressure due to reduced subcutaneous fat can aggravate the retention of water and fluid. Edema often spreads gradually from the foot to the whole body. 5. Other causes of systemic edema: ① Mucinous edema: hypothyroidism, when the condition is severe, produces characteristic non-depressed edema called mucinous edema because the skin is infiltrated by mucin and mucopolysaccharide. It often occurs on the face and in front of the tibia. ②Drug edema: The application of certain drugs can cause edema, which is characterized by mild edema after the use of drugs and gradually subsides after stopping the drugs. The more common drugs are adrenocorticotropic hormone, testosterone, estrogen, insulin, etc., and rosemary, thiourea and licorice in excessive doses can also cause edema. It is characterized by mild edema of the eyelids, ankles and hands 7 to 14 days before menstruation, which may be accompanied by breast tenderness and pelvic heaviness, and an increase in urination after menstruation. Idiopathic edema: mainly in the sagging parts of the body, mostly in adult obese women, often associated with emotional and mental changes, with fatigue, dizziness, headache, anxiety, insomnia and other neurological manifestations, and positive water test in the standing position.