Pulmonary infarction is a disease in which an area of the pulmonary parenchyma changes pathologically due to an acute sudden disturbance of blood circulation (thrombosis or embolism of an arterial vessel that feeds this segment). Due to the violation of blood flow in the lung, a site of necrosis is formed, and later the adjacent pleura is damaged and the infection joins.
The risk group for the development of pulmonary infarction primarily includes people suffering from pathology of the cardiovascular system, since this increases the likelihood of developing complications of a thromboembolic nature.
The main causes of pulmonary infarction:
- atrial fibrillation, congenital or postinfarction aneurysms of the heart, changes in the valve system, cardiomyopathy, infective endocarditis – with these pathologies, normal hemodynamics (blood flow) is disrupted and parietal thrombi are formed;
- artificial valves in the right parts of the heart (when blood elements come into contact with foreign material from which the graft is made, the risk of pathological clots formation increases);
- thrombosis, thrombophlebitis and phlebitis of deep and superficial veins of the lower extremities and pelvic organs;
- sepsis (due to the ingress of microorganisms into the bloodstream, pronounced changes occur in the coagulation system);
- fat embolism – due to extensive severe traumatic damage to the bone tissue (multiple fractures), small particles of adipose tissue may enter the bloodstream, which obstruct the lumen of the supply vessels;
- extensive severe burn lesions of the skin;
- disseminated intravascular coagulation syndrome.
Factors that significantly increase the risk of developing pulmonary thrombosis include:
- the postoperative period after massive surgical interventions (caesarean section, open thoracic and abdominal operations), since due to prolonged functional inactivity of the patient, pronounced congestion in the venous system of the lower extremities may develop and the risk of thrombosis may increase;
- burdened family history of thromboembolic complications (one of the closest relatives had ischemic strokes, pulmonary embolism, thrombophlebitis, acute thrombosis of the great vessels);
- long-term use of oral contraceptives (the rheological properties of the blood change);
- Vakez disease – polycythemia vera (an uncontrolled pathological increase in the amount of blood cell elements leads to a significant increase in blood viscosity);
- taking medications that increase the ability of the blood to clot;
- previously transferred splenectomy;
- hypertension in the pulmonary circulation;
- history of stroke or myocardial infarction;
- elderly age;
The main clinical manifestation that will bother the patient with the development of ischemia of a portion of the lung tissue is acute pain in the chest. Since there are no pain receptors in the lung parenchyma itself, pain syndrome develops only after the visceral pleura, which is abundantly innervated by nociceptors, is involved in the pathological process. It is this feature that explains the phenomenon that pain in necrosis (necrosis) of the lung tissue will occur only a few days after the blockage of the arterial vessel of the pulmonary circulation.
Characteristics of pain syndrome of thrombosis of arteries localized in the lung:
- the pain is sudden, sharp;
- aggravated by coughing and active breathing;
- a condition that forces the patient to take a forced position of the body (tilt of the body to the sick side, since this reduces the friction of the affected pleural sheets).
In some cases, pulmonary infarction can simulate an attack of angina pectoris or myocardial infarction (with the involvement of the pleural layer in the anterior surface of the left lung) or an “acute” abdomen (with inflammation of the diaphragmatic pleura, a clinical picture similar to peritonitis may occur).
Most patients develop pulmonary hemorrhage (discharge of “rusty” sputum or streaked with scarlet blood). With massive bleeding due to damage to a large blood vessel, signs of acute blood loss may develop (severe pallor of the skin and mucous membranes, tachycardia, decreased blood pressure).
In severe cases, patients may develop brain disorders (impaired consciousness, syncope, seizures of generalized seizures).
With an uncomplicated course of a heart attack, subfebrile fever may appear (body temperature rises to 37-38 ° C). When a secondary infection is attached, infarction-pneumonia develops, and then the hyperthermia will be more pronounced (values can reach 39-40˚С).
To make the correct diagnosis, in addition to a thorough physical examination of the patient, the appointment of a complex of laboratory and instrumental studies will be required.
During an objective examination, such deviations from the norm can be detected:
- shortening of the percussion sound (dullness) over the infarction site;
- with the development of reactive pleurisy, dullness will be detected in the lower parts of the affected lung, and the upper border of dullness will have an arched shape (correspond to the Sokolov-Ellis-Damoiseo line);
- weakening or complete absence of breathing over the heart attack and a characteristic pleural friction noise will be auscultated;
- in severe cases (with impaired blood circulation in the large circle), palpation of the abdomen will reveal hepatomegaly.
When conducting additional research in determining the diagnosis of a pulmonary infarction, the following changes will indicate:
- an increase in the number of leukocyte cells in the blood;
- an increase in the concentration of total bilirubin with a constant level of alanine aminotransferase and aspartate aminotransferase;
- an increase in the enzyme lactate dehydrogenase;
- decreased oxygenation of arterial blood;
- imaging methods (plain X-ray, CT, MRI) can determine the presence of effusion in the pleural cavity and clarify the localization of the infarction, which will look like a wedge-shaped area of the compaction of the pulmonary parenchyma;
- on the ECG, signs of overload of the right heart will be determined, and the reasons that could lead to the development of embolism (arrhythmias, cardiomyopathy) can be identified;
- angiopulmonography will allow you to see in which artery there was a violation of blood flow.
To prevent the development of painful shock during a pulmonary infarction, first of all, it is necessary to carry out adequate analgesia (non-narcotic and narcotic pain medications are used).
To prevent the progression of thromboembolic complications of a heart attack, adequate thrombolytic therapy with direct and indirect anticoagulants should be prescribed. The disadvantage of this method is a large number of contraindications and complications, therefore, anticoagulant treatment is not indicated for everyone.
It is possible to reduce or completely dissolve an already formed thrombus during a heart attack only with the help of fibrinolytic therapy using streptokinase or saruplase.
To improve blood oxygenation, all patients need inhalation. When an infection joins, the appointment of broad-spectrum antibacterial drugs is required.
If conservative therapy is ineffective, the attending physician decides to carry out surgical treatment. Surgical intervention may involve removing a blood clot that obstructs the supplying vessel (thrombectomy) and placing a special venous filter in the inferior vena cava (to prevent recurrent episodes of thromboembolism from the veins of the lower extremities).
Preventive measures for pulmonary infarction should include:
- treatment of diseases that cause the development of pulmonary infarction (elimination of arrhythmias, treatment of phlebitis and thrombophlebitis);
- tight bandaging of the legs before the operation;
- early activation of the patient in the postoperative period (shortening of bed rest, physiotherapy exercises from the first days);
- normalization of lifestyle (weight loss, rejection of bad habits);
- adequate daily physical activity (walking, running, exercise).
Lung infarction is a serious pathological condition that can lead to sudden death of the patient. To prevent the development of this disease, it is required to carry out preventive measures among people who are at increased risk of developing thromboembolic complications.