Pulmonary infarction is an ischemia of a section of lung tissue caused by thrombosis or embolism of branches of the pulmonary artery. Clinical signs of this pathology can be sharp chest pain, shortness of breath, cough with bloody sputum, hyperthermia, tachycardia, collapse. To detect a pulmonary infarction, radiography, CT and lung scintigraphy, angiopulmonography, EchoCG, blood gas composition study are informative. Treatment begins with the appointment of anticoagulants and fibrinolytics, oxygen therapy; if necessary, an embolectomy is performed. In case of infarction-pneumonia, antibiotic therapy is indicated.
ICD 10
I26 I28
Meaning
Pulmonary infarction (pulmonary embolism) is a circulatory disorder in a limited area of the pulmonary parenchyma that develops as a result of blockage of the lobular, segmental and smaller arteries of the lung by a thrombus or embolus. According to the data available in pulmonology, pulmonary infarction accounts for 10-25% of all cases of PE. The diagnosis of pulmonary thromboembolism is often not established in vivo, which leads to a large number of unrecognized episodes of pulmonary infarction. At the same time, the fatal outcome from pulmonary embolism is recorded in 5%-30% of patients. Lack of treatment, recurrent thrombosis, the presence of background pathology are the main factors that increase the risk of fatal cases of pulmonary embolism. Infarction of the right lung occurs 2 times more often than the left, while the lower lobes of the lungs are affected 4 times more often than the upper ones.
Causes of pulmonary infarction
Pulmonary infarction most often develops in patients suffering from cardiovascular pathology: atrial fibrillation, mitral stenosis, coronary artery disease and myocardial infarction, cardiomyopathy, infectious endocarditis, atrial myxoma, heart failure, vasculitis, etc. In this case, blood clots are usually formed in the auricle of the right atrium and, under certain conditions, are carried with the blood flow into the arteries of the small circle. Often the cause of pulmonary embolism is thrombosis of the veins of the lower extremities, thrombophlebitis of the deep veins of the pelvis. In these cases, the greatest danger is represented by floating thrombi having one fixation point in the distal part of the venous vessel.
Multiple fatty embolisms of the lungs often become a complication of fractures of tubular bones. It is known that bed rest or immobilization of the limbs even for one week significantly increases the risk of embologenic thrombosis. Pulmonary infarction can develop in the postpartum and postoperative period – more often after cesarean section, extensive abdominal, thoracic and gynecological operations, hemorrhoidectomy.
Secondary factors predisposing to pulmonary thromboembolism include recurrent venous thrombosis in the anamnesis, hereditary burden of PE, age over 60 years, hormonal contraception, obesity, pancreatic tumors, pulmonary hypertension, etc. Potentially dangerous background blood diseases are sickle cell anemia, polycythemia, DIC syndrome, heparin-induced thrombocytopenia.
A pulmonary infarction develops in the period from several hours to a day after obturation of the lobular and segmental branches of the pulmonary artery with thromboembolism; the complete organization of the infarction takes about 7 days. The ischemic area has the shape of a wedge (pyramid) of various sizes with the base directed towards the periphery, and the tip facing the root of the lung. The affected area is characterized by a dark cherry color, dense consistency, protrudes above the surface of healthy lung tissue. The pleura acquires a dull, matte shade; hemorrhagic contents often accumulate in its cavity. The outcomes of a pulmonary infarction can be: complete resorption, compaction, scarring, destructive changes in the lung (abscess, gangrene).
Classification
Pulmonary infarction is one of the clinical variants of PE, along with sudden shortness of breath of unknown origin and acute pulmonary heart. Depending on the level of pulmonary artery obstruction by thromboembolism, there are:
- massive thromboembolism (embolization of the main trunk or the main branches of the pulmonary artery)
- submassive thromboembolism (blockage at the level of lobular and segmental branches)
- thromboembolism of small pulmonary arteries.
A pulmonary infarction can be primary (with an unknown source of thromboembolus detachment) and secondary (complication of venous thrombophlebitis); limited (with obturation of the subsegmental branches of the pulmonary artery) and extensive (the affected area extends over a large area); uncomplicated and complicated (hemoptysis, abscessing, pleural empyema, sepsis).
Thromboembolism of the branches of the pulmonary arteries causes ischemia of the pulmonary parenchyma site, followed by overflow of the damaged lung tissue with blood that enters it from areas with normal vascularization. With this mechanism, a hemorrhagic form of pulmonary infarction develops. In the affected area, conditions are created for the development of infection, which leads to the occurrence of infarct-pneumonia. In other cases, the branch of the pulmonary artery is blocked by an infected embolus – in this case, the destruction of the parenchyma and the formation of a lung abscess occur.
Pulmonary infarction symptoms
The clinical picture of a pulmonary infarction usually manifests 2-3 days after the blockage of a branch of the pulmonary artery by a thrombus. Suddenly there is an acute pain in the chest; by nature it resembles the pain of angina pectoris, it increases with coughing, breathing, and bending of the trunk. The cause of pain is reactive pleurisy in the necrotic area of the lung. In the case of a reaction of the diaphragmatic pleura, the development of a clinic of “acute abdomen” is possible. In 30-50% of patients, hemoptysis occurs (in the form of individual veins or the appearance of “rusty sputum), in 2-6% – pulmonary bleeding.
Hyperthermia in pulmonary infarction has the character of subfebrility, it can persist for 1-2 weeks, with infarct pneumonia, the temperature rises to 38-39 ° C. These symptoms are accompanied by shortness of breath and tachypnea (more than 20 per minute), tachycardia with a heart rate > 100 beats. in min., arrhythmia (extrasystole, atrial fibrillation or atrial fibrillation), pallor or cyanosis of the skin, arterial hypotension up to collapse.
50% of patients diagnosed with a pulmonary infarction develop serous or hemorrhagic pleurisy. Occasionally, patients have cerebral disorders, manifested by fainting, convulsions, coma; jaundice caused by secondary liver changes and increased hemoglobin breakdown; dyspeptic phenomena (hiccups, nausea, vomiting, abdominal pain). Infection of the site of a pulmonary infarction can lead to the development of bacterial pneumonia, candidiasis of the lungs, abscessing pneumonia, abscess or gangrene of the lung.
Diagnostics
Diagnosis of a pulmonary infarction requires coordination of the efforts of a pulmonologist and a cardiologist. Physical studies in pulmonary infarction reveal weakened breathing, small-bubbly wheezing, pleural friction noise; shortening of percussion sound; systolic noise, gallop rhythm, accent and splitting of the II tone on the aorta. Palpation of the abdomen may reveal an increase in the liver, its soreness.
In laboratory tests (blood test, biochemical blood examination, analysis of blood gas composition), moderate leukocytosis, increased activity of lactate dehydrogenase, total bilirubin (at normal values of transaminases), signs of arterial hypoxemia are noted. According to ECG data, it is possible to detect signs of overload of the right parts of the heart, incomplete blockade of the right leg of the Gis bundle. EchoCG markers of a pulmonary infarction may include dilation and hypokinesia of the right ventricle, increased pressure in the pulmonary artery, the presence of a blood clot in the right parts of the heart, etc. Ultrasound of the veins of the lower extremities often allows you to diagnose deep vein thrombosis.
Radiography of the lungs in direct and lateral projections (as well as CT or MSCT of the lungs) reveals the expansion and deformation of the lung root, the area of reduced transparency in the form of a wedge, the presence of effusion in the pleural cavity. Angiopulmonography reveals obstruction of the branches of the pulmonary artery due to intra-arterial filling defects. Lung scintigraphy is used to confirm the presence of areas of decreased lung perfusion.
Based on the analysis of the clinical picture and laboratory and instrumental data, pulmonary infarction has to be differentiated with croup pneumonia, spontaneous pneumothorax, lung atelectasis, myocardial infarction, pericarditis, myocarditis, rib fracture, etc.
Treatment for pulmonary infarction
First aid for a pulmonary infarction should be provided as early as possible. First of all, it is necessary to stop the pain syndrome with the help of non-narcotic or narcotic analgesics and immediately hospitalize the patient in the ICU.
Direct (heparin, fraxiparin) and indirect anticoagulants (fenindione, warfarin) are used to prevent further thrombosis and prevent the increase of an already formed thrombus under the control of coagulogram indicators. Anticoagulant therapy is contraindicated in bleeding, hemorrhagic diathesis, gastric ulcer and duodenal ulcer, malignant neoplasms. Fibrinolytic therapy with streptokinase, urokinase, and tissue plasminogen activator is prescribed to dissolve blood clots.
In case of pulmonary embolism complicated by arterial hypotension, vasopressors (norepinephrine, dopamine), rheopolyglucin are injected intravenously. In case of signs of infarct-pneumonia, antibiotic therapy is performed. Patients with a pulmonary infarction need oxygen inhalation through a nasal catheter. In the absence of positive dynamics from conservative treatment, it is possible to perform thromboembolectomy from the pulmonary artery with the installation of a cava filter in the inferior vena cava system. To assess the indications for surgical treatment, the patient must be examined by a vascular or thoracic surgeon in a timely manner.
Prognosis and prevention
With properly and timely organized therapy, a pulmonary infarction does not pose a great threat to life. In rare cases, it can lead to sudden death. The risk of an unfavorable outcome increases in the presence of severe heart failure, relapses of PE, the development of various complications (postinfarction pneumonia, pulmonary edema, suppurative processes).
Taking into account the causes of a pulmonary infarction, prevention may include timely treatment of thrombophlebitis, therapeutic gymnastics and early recovery after surgery, wearing compression knitwear for diseases of the veins of the lower extremities, compliance with the terms of use of intravenous catheters for infusion therapy.
Literature
- Pulmonary infarction in acute pulmonary embolism. Kaptein FHJ, Kroft LJM, Hammerschlag G, Ninaber MK, Bauer MP, Huisman MV, Klok FA. Thromb Res. 2021 Jun;202:162-169. link
- Abstracts of Presentations at the Association of Clinical Scientists 143rd Meeting Louisville, KY May 11-14,2022. [No authors listed] Ann Clin Lab Sci. 2022 May;52(3):511-525. link
- Pulmonary Embolism Presenting with Pulmonary Infarction: Update and Practical Review of Literature Data. Gagno G, Padoan L, D’Errico S, Baratella E, Radaelli D, Fluca AL, Pierri A, Janjusevic M, Aleksova Noveska E, Cova MA, Copetti R, Cominotto F, Sinagra G, Aleksova A. J Clin Med. 2022 Aug 21;11(16):4916. link
- Clinical relevance of pulmonary infarction in patients with pulmonary embolism. Cha SI, Shin KM, Lee J, Hwangbo Y, Yoo SS, Lee J, Lee SY, Kim CH, Park JY, Jung TH. Thromb Res. 2012 Sep;130(3):e1-5. link
- Pulmonary embolism, pulmonary hemorrhage and pulmonary infarction. Dalen JE, Haffajee CI, Alpert JS 3rd, Howe JP, Ockene IS, Paraskos JA. N Engl J Med. 1977 Jun 23;296(25):1431-5. link