Lower extremity venous thrombosis refers to the formation of blood clots in the venous vessels of the lower extremities, the affected limbs early pain, swelling, skin bruising, superficial venous embolism along the damaged veins can be felt as a strip of tenderness; late dorsalis pedis, posterior tibial artery pulsation disappeared, shock and venous gangrene of the limbs (ulceration, necrosis); the acute stage of the thrombus at any time due to thrombus detachment of the embolus embolus occurred in the lungs embolism, leading to sudden death in severe cases. Etiology Stagnant blood flow, hypercoagulation of blood and damage to the vessel wall are the three main factors contributing to the formation of venous thrombosis, one of which may play a dominant role, while the other factors complement each other to form a thrombus. Any situation involving the above factors can lead to venous thrombosis, such as: a. Surgery Damage to the endothelium, especially orthopedic, thoracic, abdominal and genitourinary surgery; b. Tumor The exact mechanism is not clear, and it is usually believed that cancer-causing factors can activate the coagulation waterfall, forming a pro-thrombotic environment, especially pancreatic, lung, gonadal, mammary gland, and urologic malignant tumors; c. Trauma Particularly spinal, pelvic, and lower extremity fractures Prolonged bed rest, one of the slow blood flow factors; v. Pregnancy, the role of estrogen; vi. Hypercoagulable state, anticoagulant deficiency, myeloproliferative diseases, anomalous fibrinogenemia, and disseminated intravascular coagulation, etc.; vii. Phlebitis or medical endothelial injury, such as venous interventional therapy operations. Diagnosis I. Clinical manifestations 1. Thrombosis of superficial veins (i.e., thrombosed superficial phlebitis) occurs in superficial veins (those with clearly visible greenish-purple blood vessels), such as the great saphenous vein and the small saphenous vein. The disease is prone to recurrent episodes. In the acute stage, the affected limbs have localized pain and swelling, and along the damaged veins, a stripe with pressure and pain can be felt, and the skin temperature is high, red and swollen. 1~3 weeks later, the venous inflammation gradually subsides, and the localized stripe and skin pigmentation remain, which does not subside for a long time. 2.Deep Vein Thrombosis (DVT) can occur in any part of the veins of the lower extremities, and the symptoms may be mild or severe depending on the location of the thrombus. About 2/3 of DVT is asymptomatic. (1) When the thrombus only occurs in the deep veins of the calf (peripheral type), the symptoms are not obvious, manifested as mild calf swelling and pain, gastrocnemius muscle light pressure pain, localized sense of heaviness, so it is easy to be ignored; when the thrombus from the calf to the thigh to continue to extend, the calf swelling, pain is becoming increasingly obvious, the superficial veins below the groin are dilated, swollen, the femoral triangle (the inner side of the thigh close to the groin of the triangular zone of about 3M2) there can be obvious pressure pain, and then form the iliofemoral vein, which is the most common form of DVT. At this time, iliofemoral vein thrombosis (central type) is formed, at this time, it can be accompanied by fever, fatigue, tachycardia, blood leukocyte increase and other systemic symptoms. If the thrombus is dislodged, it can cause pulmonary embolism, which has more serious consequences. When pulmonary embolism occurs, cough, chest pain, dyspnea, and even cyanosis, shock, and sudden death can occur. (2) If the whole lower limb deep venous system extensive thrombosis (mixed type), not only the thrombus causes venous obstruction, at the same time stimulate the artery strong spasm, then the lower limb pain is severe, the whole limb extensive obvious swelling, the skin is tense, shiny, purplish-brown, and some of them can occur blisters, the dorsal foot, the arterial pulsation of the back of the tibia is disappeared, and there can be shock and venous gangrene of the limb (ulceration, necrosis), and this special type is also known as This special type is also called “femoral bruise”. With typical clinical manifestations as above, it is generally not difficult to diagnose. Second, auxiliary examination In order to further determine the location, degree and scope of the lesion, the following examination methods can be taken: 1, ultrasonic examination: this method is the more commonly used examination methods. Through ultrasound can directly observe the diameter of the vein and the lumen situation, can understand the embolism of the large and where it is located. Color flow Doppler real-time imaging method has good specificity and sensitivity (up to 95%) for deep vein thrombosis above the knee. 2, CT or MR venography: non-invasive, accurate, intuitive, and can simultaneously observe the inferior vena cava and iliac veins around the mass compression and other factors of thrombosis. 3.Venography: it is the most accurate examination method, which can effectively determine the presence or absence of thrombus, the size, location, morphology of thrombus and collateral circulation. At the same time, retrograde imaging can also be done to understand the function of venous valves. However, since this method has certain damage, it may also cause allergic reaction or renal function damage, so it is performed only when necessary. Treatment I. Treatment of thrombosed superficial phlebitis 1. General treatment: bed rest, elevate the affected limb above the level of the heart, apply hot compresses locally, and wear elastic stockings or wrap with elastic bandage if necessary. Avoid standing or sitting for a long time. 2.Drug treatment: painkillers are: POTAZONE, INDOMECINE (anti-inflammatory pain), PIROXICORN (YANAOXICORN), ASPIRIN, etc. Generally, it is not necessary to use antibiotic treatment. It is recommended to use low molecular heparin and other anticoagulant therapy when superficial vein thrombosis is extensive in the acute stage to avoid thrombus spreading to the deep venous system leading to pulmonary embolism. Treatment of deep venous thrombosis 1, general treatment: bed rest, elevate the affected limb above the heart level, about 20-30cm from the bed, and slightly flex the knee joint. Keep the bowel clear, avoid hard defecation to make thrombus dislodgement leading to pulmonary embolism. After getting up, wear long compression stockings for 6 weeks to 3 months. 2.Anti-coagulation therapy (1)Heparin: Intravenous heparin can make the partial thromboplastin time (APTT) reach 1.5-2 times of normal, and maintain the treatment for 5-7 days. However, the dosage of intravenous heparin is difficult to control, and carelessness may cause bleeding, so the safer method is to use low molecular weight heparin, subcutaneous injection. (2) Warfarin: Warfarin is given orally after 5 days of heparin treatment until the coagulation INR index (prothrombin time, PT) reaches 2-2.5 times the normal level. Subsequently, a maintenance dose is given for 3-4 months. 3.Thrombolytic therapy: commonly used drugs are urokinase, streptokinase and fibrinolytic enzymes. Because it is easier to cause bleeding, its long-term efficacy is not better than anticoagulation therapy, so it is generally used only when combined with pulmonary embolism. For patients who can not use anticoagulation therapy, and the risk of pulmonary embolism is low, you can try to use elevated limbs and localized hot compresses. 4.Interventional therapy: permanent and temporary vena cava filter implantation. It is generally believed that the following cases are indicative of vena cava filter implantation: (1) the patient has suffered a pulmonary embolism event; (2) the thrombus has spread to the inferior vena cava; (3) the patient has suffered an embolism event despite standardized anticoagulation; (4) the patient has a hemorrhagic phenomenon in the presence of the patient can not be used to use anticoagulants; (5) the patient is in the perioperative period of cerebrovascular accidents or major surgical procedures, anticoagulation may lead to fatal hemorrhage; ( (6) Floating thrombus in the iliac vein; In addition to the above, the indications for implantation of temporary filters are: (1) Severe multiple trauma; (2) Major surgeries that are prone to venous embolism events, such as hip replacement, and so on. Of course, there are some relative indications for implantation of vena cava filter, such as: (1) deep vein thrombosis or thrombolysis with the use of; (2) malignant tumor patients are expected to survive for more than 2 years; Prevention 1, postoperative, post-partum and other long-term bedridden: patients should be encouraged to carry out active activities of the lower limbs in bed, and to make deep breathing and coughing; can get up as early as possible to get out of bed, to promote the activity of calf muscles to increase the venous return of the lower limbs. The patients who can get up should get out of bed as early as possible to promote the activity of calf muscles and increase the venous return of lower limbs. Active treatment of varicose veins: early removal of venous cannulae can effectively prevent venous thrombosis. For those who have the tendency of deep vein thrombosis and have to be operated: small-dose heparin and oral warfarin can be used to prevent it before operation. Low molecular heparin anticoagulation can be started 6 hours after operation for patients with high risk of thrombosis. 4.Patients with existing calf vein thrombosis: it should also be handled as early as possible when it is formed, in order to prevent the thrombus from extending to the femoral vein or thrombus dislodgement. 5. Patients at high risk of thrombosis: antithrombotic stockings should be worn to prevent thrombosis. After the treatment of deep vein thrombosis, patients should wear medical compression stockings for a long time to prevent the sequelae of deep vein thrombosis.