Pediatric pulmonary embolism
Introduction
Introduction to pulmonary embolism in children Pulmonary embolism (PE) is a general term for a group of diseases or clinical syndromes in which the embolus is blocked by various embolisms. In the past, children's PE has been considered to be rare in clinical practice. However, a large number of data and autopsy at home and abroad have confirmed that this disease is not a rare disease. The risk of PE in the presence of primary disease is the main cause of PE in children, such as congenital heart disease and infectivity. Endocarditis, nephrotic syndrome with hypercoagulable state, etc. basic knowledge The proportion of illness: 0.001% Susceptible people: children Mode of infection: non-infectious Complications: myocarditis nephrotic syndrome leukemia thrombocytopenia malnutrition
Cause
Causes of pulmonary embolism in children
Causes:
The emboli source of PE in children is different from that in adults. Because children's lower extremity DVT and pelvic thrombosis are rare, PE caused by detachment of embolism from these sites is not a common cause. Children's emboli sources are scattered, compared with adults. Caused by congenital diseases (such as congenital heart disease, sickle cell anemia) or iatrogenic factors (such as indwelling intravenous catheters, parenteral nutrition), 90% of pulmonary embolism originates from the lower extremity vein (femoral vein) And pelvic veins of the thrombosis, certain diseases such as bacterial endocarditis, myocarditis, nephrotic syndrome hormone therapy, leukemia, polycythemia, thrombocytopenia, or facial features, urinary tract, complications after intestinal infection , as well as intravenous drip, intracardiac intubation, postoperative complications, etc., can also be seen in children with prolonged bed rest, malnutrition, diarrhea and dehydration, occasionally in sickle cell anemia, fatty embolism is more common in fractures Rear.
Pathogenesis:
The formation of venous thrombosis is related to the following three causes: 1. venous blood stasis, 2. vascular endothelium or epithelial cells are damaged, 3. blood coagulation is increased, clots fall off due to some reason after thrombosis, from the surrounding The venous system flows down the blood into the right ventricular cavity, re-enters the pulmonary artery, and embeds and blocks the pulmonary artery of different sizes. Due to the blockage of blood flow, the alveolar cavity, lung collapse and loss of surfactant are caused by local lung tissue. .
Prevention
Pediatric pulmonary embolism prevention
Prevention of embolism and infarction in the lungs, mainly for long-term patients, especially after surgery should pay attention to early active and passive activities, massage therapy to reduce the chance of blood flow stagnation, should pay attention to fluid intake, avoid blood circulation Stasis or stagnation, maintenance of nutrition is also important, prevent PE can be used venous filter, suitable for patients with lower extremity venous thrombosis, to prevent emboli from falling into the lungs.
Complication
Pediatric pulmonary embolism complications Complications Myocarditis Nephrotic syndrome Leukemia Thrombocytopenia Malnutrition
Pulmonary embolism itself is often bacterial endocarditis, myocarditis, nephrotic syndrome hormone therapy, leukemia, polycythemia, thrombocytopenia, or facial features, urinary tract, complications after intestinal infection, and intravenous drip, heart Endoscopic examination, postoperative complications, long-term bed rest, malnutrition, diarrhea and other complications, severe or extensive pulmonary embolism, acute respiratory failure and heart failure are common complications of pulmonary embolism.
Symptom
Pediatric pulmonary embolism symptoms common symptoms vascular murmur cyanosis shortness of breath chest pain dyspnea heart failure irritability tachycardia tachycardia shock
The clinical manifestations of PE in children are similar to those in adults. The symptoms and signs are not specific, and the changes are quite large, ranging from asymptomatic to hemodynamic instability and even sudden death.
Pulmonary embolism symptomology
Have difficulty breathing and shortness of breath, especially after activity, chest pain, including pleural inflammatory chest pain or angina pectoris-like chest pain; syncope can be the only or first symptom of pulmonary embolism, irritability, panic or sudden death; often a small amount of hemoptysis, Large hemoptysis is rare, coughing, palpitations; large or extensive pulmonary embolism can cause acute pulmonary heart disease.
2. Signs
There are shortness of breath, tachycardia, blood pressure changes, blood pressure drops or even shock in severe cases, cyanosis, fever, mostly low fever, a small number of patients may have moderate fever; jugular vein filling or pulsation, lungs can smell and snar Beep and (or) wet voice, even audible and vascular murmur, pulmonary artery second tone hyperthyroidism or division, P2> A2, tricuspid systolic murmur; may have corresponding signs of pleural effusion.
Examine
Pediatric pulmonary embolism examination
1. Non-specific examination: including blood routine.
2. Arterial blood gas analysis: blood gas is often characterized by hypoxemia and hypocapnia, alveolar-arterial oxygen partial pressure difference (PA-O2) is elevated, and some patients can be normal.
3. Plasma D-dimer (D-dimer) This test has become an important preliminary screening test for clinical diagnosis of PE. D-dimer is a soluble degradation product produced by cross-linked fibrin under the action of fibrinolysis system. A specific fibrinolysis process marker, in thromboembolic thrombocytosis, increased blood concentration due to thrombolysis, D-dimer diagnostic sensitivity of acute PE is 92% to 100%, but its specificity Sexually low, only 40% to 43%, surgery, tumor, inflammation, infection, tissue necrosis, etc. can increase it, if its content is less than 500g / L, can basically exclude acute PE, ECG, lung function, Echocardiography, etc. have certain implications, but they cannot be used as a basis for diagnosis.
Auxiliary inspection
1. X-ray examination of the lungs: many abnormal findings, such as: regional pulmonary vascular texture thinning, sparse or disappearing, increased lung field brightness; local infiltrative shadow in the lung field, wedge-shaped shadow pointing to the hilum; lung not Zhang or lung insufficiency and so on.
2. Electrocardiogram: about 30% abnormality, common T1 wave change of V1V4 and ST segment abnormality, right bundle branch block, right axis deviation, clockwise transposition, etc., but its change is non-specific, X Early changes in lines and ECGs are often inconspicuous and are easily missed.
3. Radionuclide ventilation/perfusion scan: an important diagnostic method for PE. Typical signs can be used as a basis for diagnosis. The distribution of radionuclides is proportional to pulmonary blood flow, which is characterized by sparse distribution of lungs, lung segments or multiple sub-segments. Or defect, and ventilation imaging is normal or near normal.
4. Spiral CT and electron beam CT angiography: due to its non-invasiveness, it can be found in the pulmonary arteries above the segment, which is one of the confirmed examinations.
5. Magnetic resonance imaging (MRI) has higher sensitivity and specificity for the diagnosis of pulmonary embolism above segment, and patients are more acceptable. MRI has the potential to identify new and old thrombus, which may become the basis for determining thrombolysis in the future. .
6. Pulmonary angiography: still the "gold standard" for the diagnosis of PE, the sensitivity is 98%, the specificity is 95% to 98%, but because of its invasiveness, it is not used as a first-line examination method.
Diagnosis
Diagnosis and diagnosis of pulmonary embolism in children
diagnosis
Children with PE risk factors should be highly vigilant. When sudden breathing difficulties, chest pain, cough, hemoptysis, shock, syncope, paroxysmal or progressive congestive heart failure, high degree of suspicion of pulmonary embolism, combined with chest radiograph, electrocardiogram, Arterial blood gas examination can initially suspect or exclude other diseases, and quickly detect D-dimer (ELISA method) as soon as possible, such as less than 5000g / L, can basically exclude acute PE; if greater than or equal to 500g / L, can be first echocardiography Figure examination, if there is no obvious abnormality, continue to carry out radionuclide ventilation / perfusion scan or CT angiography diagnosis, the above methods can not be diagnosed, pulmonary angiography should still be performed, clinically suspected large-area embolization patients, due to the presence of shock or low Blood pressure, critical condition, can be firstly performed by echocardiography. For acute large-area PE, it can show signs of acute pulmonary hypertension and right ventricular overload. If it is highly suspected, it can be treated according to the ultrasound results. After the patient's condition is stable, Other tests, such as radionuclide perfusion ventilation and CT angiography, are performed to confirm the diagnosis.
Differential diagnosis
Differential diagnosis includes large leaf pneumonia, aspiration pneumonia, atelectasis, pneumothorax, pleurisy, asthma, dissecting aortic aneurysm and myocardial infarction, pericardial tamponade, restrictive cardiomyopathy, constrictive pericarditis and right heart failure, etc., pulmonary embolism Such as secondary bacterial infection, can form a lung abscess.
