Pulmonary embolism and pulmonary infarction
Introduction
Introduction to pulmonary embolism and pulmonary infarction Pulmonary embolism (PE), also known as pulmonary thromboembolism, is a clinical and pathophysiological syndrome that causes pulmonary circulatory disorders by endogenous or exogenous emboli to block the trunk or branches of the pulmonary artery. If lung hemorrhage or necrosis occurs further on this basis, it is called pulmonary infarction, and it is sometimes difficult to distinguish between the two in clinical practice. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: pulmonary hypertension
Cause
Pulmonary embolism and cause of pulmonary infarction
Age factor (25%):
Autopsy data showed that the age of PE was 50-65 years old, the prevalence rate of children was about 3%, and that of 60% was over 20%, 90% of lethal PE occurred over 50 years old, and women were 20-39 years old. The incidence of deep vein thrombosis is 10 times higher than that of men of the same age, so the incidence of PE is relatively high.
Reduced activity (18%):
Due to lower limb fractures, convulsions, severe heart and lung disease, surgery and other reasons, long-term inappropriate bed rest, or healthy people's normal physical activity, reducing the driving force of venous blood flow, leading to stagnant blood flow, deep vein thrombosis.
Varicose veins and thrombophlebitis (15%):
Pulmonary angiography and pulmonary perfusion scans show that about 51% to 71% of patients with deep venous thrombosis of the lower extremity may have PE, because of varicose veins and patients with deep vein thrombophlebitis, for various reasons, once the venous pressure rises sharply or The venous blood flow suddenly increases, and the embolus falls off and PE occurs.
Cardiopulmonary disease (15%):
25% to 50% of PE patients have cardiopulmonary disease, especially those with atrial fibrillation and heart failure. According to more than 900 cases of heart disease autopsy in Fuwai Hospital, 11% of PE patients, especially rheumatoid heart. Disease, cardiomyopathy, chronic obstructive pulmonary disease and pulmonary heart disease are more.
Trauma (10%):
15% of patients with trauma complicated with PE, in which the humerus, pelvis, and spinal fractures are often prone to PE (the formation of emboli due to fat droplets in the bone marrow); in addition, soft tissue damage and extensive burns may also be complicated by PE, possibly due to the release of certain tissues from injured tissues. The substance damages the endothelial cells of the pulmonary blood vessels or causes hypercoagulability.
Tumor (7%):
Many tumors such as pancreatic cancer, lung cancer, colon cancer, gastric cancer, osteosarcoma, etc. can be combined with PE. The reason for the increased incidence of PE in cancer patients may be that the tumor cells themselves can be used as emboli, and the coagulation mechanism of tumor patients is often abnormal.
Pregnancy and birth control pills (5%):
The thromboembolic disease of pregnant women is 7 times higher than that of non-pregnant women of the same age. The incidence of venous thrombosis in women taking contraceptives is 4 to 7 times higher than that of non-medicated patients. It has recently been reported that intravenous infusion of estrogen can also induce PE [2].
Other reasons (3%):
Obesity, certain blood diseases (such as polycythemia, sickle cell disease), diabetes, pulmonary cysticercosis.
Prevention
Pulmonary embolism and prevention of pulmonary infarction
In view of the many limitations of treatment. Prevention of PE is extremely important. The choice of preventive measures and their strength are based on clinical factors that are prone to venous blood flow stagnation and thromboembolism. Prophylactic treatment of venous thromboembolism includes low-dose unfractionated heparin (LDUH), low molecular weight heparin (LMWH), dextran injection, warfarin, intermittent balloon compression (IPC), and progressively pressurized elastic stockings. Aspirin does not prevent venous thromboembolism in general surgery patients.
Complication
Pulmonary embolism and pulmonary infarction complications Complications pulmonary hypertension
Pulmonary infarction is a further development of pulmonary embolism. In the actual situation, once the blood flow is blocked, the proximal capillary network is enhanced by the hypoxia permeability of the wall, and the fluid and red blood cells are exuded. The alveolar cavity exudates. The increase will inevitably affect the gas exchange, and then the pulmonary infarction will occur. This is the reason that the nearer part of the small arterial branch is more likely to cause infarction and infarction before the infarction. It is easy to form pulmonary infarction after surgery or trauma, especially the concomitant heart. In patients with vascular disease, pulmonary infarction is more likely to form on the basis of pulmonary congestion.
The disease is caused by acute pulmonary hypertension and right heart failure, followed by lung ischemia, hypoxia and left cardiac output, and circulatory failure.
Symptom
Pulmonary embolism and pulmonary infarction symptoms common symptoms atelectasis lung texture reduction hemoptysis chest pain pulmonary embolism venous thrombosis dyspnea pulmonary circulatory embolism sudden right heart failure
1, sudden breathing difficulties, severe chest pain, hemoptysis, and even syncope and other symptoms.
2, breathing and heart rhythm increase, lung rales, pulmonary heart valve second heart sound hyperthyroidism, chest radiograph showing patchy or wedge-shaped lungs, discoid atelectasis one side of the diaphragm elevation, pulmonary artery thickening and localized lung The texture is reduced.
3, ECG and heart vector have right heart involvement performance: severe clockwise transposition, lung p wave, electric axis right deviation and other changes.
4, blood gas analysis PaO240%; blood lactate dehydrogenase> 450U, aspartate aminotransferase (AST) and creatine phosphokinase (CPK) normal hemoglobin increased.
5, lung ventilation / perfusion (V / Q) scan showed Vn / Qo (n normal, q did not perfusion).
6. Pulmonary angiography, the X-ray signs are pulmonary vascular defects or pulmonary artery occlusion, this method is the most accurate and reliable measure for the diagnosis of pulmonary embolism.
7, such as suspicious lower extremity deep vein thrombosis, feasible limb venography, Doppler ultrasound vascular examination.
Examine
Pulmonary embolism and pulmonary infarction
1, coagulation factors, out, clotting time, fibrinogen degradation products, soluble fibrin complex, blood rheology and blood gas analysis.
2, pulmonary function tests, including alveolar oxygen partial pressure and arterial oxygen partial pressure difference, ventilation and perfusion ratio and dead space / tidal volume ratio.
3, ECG, heart vector, echocardiography.
4, chest X-ray film, if there are conditions for CT and MRI examination.
5. Pulmonary ventilation/perfusion imaging, pulmonary angiography or digital subtraction angiography.
6, such as suspicious lower extremity deep vein thrombosis, feasible limb venography, Doppler ultrasound vascular examination.
Diagnosis
Diagnosis of pulmonary embolism and pulmonary infarction
Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.
Differential diagnosis
There are many diseases that need to be differentiated from pulmonary embolism and pulmonary infarction, including acute myocardial infarction, coronary insufficiency, pneumonia, pleurisy, atelectasis, asthma, dissection aneurysm, primary pulmonary hypertension and snoring.
The thinking of differential diagnosis is as follows:
1 characteristics of symptoms and signs.
2 accompanying symptoms and signs.
3 tips for related medical history.
4 results of laboratory tests.
Taking dyspnea as an example, dyspnea in pulmonary embolism is sudden, often accompanied by chest pain, hemoptysis, shock or syncope. If the medical history suggests some risk factors such as fracture or long-term braking, laboratory tests reveal venous thrombosis of the lower extremity. Learning to show pulmonary hypertension or right ventricular enlargement or even found pulmonary obstruction, that is, it is not difficult to identify with other diseases.
