Lung abscess is a nonspecific inflammation of the lung tissue, as a result of which melting occurs with the formation of purulent-necrotic cavities. During the formation of the abscess, fever, thoracalgia, dry cough, intoxication are noted; during the opening of the abscess, cough with copious discharge of purulent sputum. The diagnosis is made on the basis of a combination of clinical, laboratory data, X-ray picture. Treatment involves massive antimicrobial therapy, infusion-transfusion therapy, a series of rehabilitation bronchoscopes. Surgical tactics may include abscess drainage or lung resection.
Lung abscess is included in the group of “infectious lung destructions”, or “destructive pneumonitis”. Among all suppurative processes in the lungs, abscess accounts for 25-40%. Lung tissue abscesses are 3-4 times more common in men. A typical portrait of a patient is a middle-aged man (40-50 years old), socially unsettled, abusing alcohol, with a long experience as a smoker. More than half of the abscesses are formed in the upper lobe of the right lung. The relevance of the problem in modern pulmonology is due to the high frequency of unsatisfactory outcomes.
Causes of lung abscess
Staphylococcus aureus, gram-negative aerobic bacteria and non-spore-forming anaerobic microorganisms are the most common cause of lung abscess. Pathogens most often penetrate into the lung cavity by bronchogenic route. As a provoking factor are:
- Lesions of the mouth and ENT organs. In the presence of inflammatory processes in the oral cavity and nasopharynx (periodontal disease, tonsillitis, gingivitis, etc.), there is a possibility of infection of the lung tissue.
- Aspiration. Aspiration by vomit, for example, in an unconscious state or in a state of alcoholic intoxication, ingestion of foreign bodies can also cause lung abscess.
- Lesion of the pulmonary vessels. Secondary bronchogenic infection is possible with a lung infarction, which occurs due to an embolism of one of the branches of the pulmonary artery.
- Sepsis. Variants of infection by hematogenic pathway, when the infection enters the pulmonary capillaries with bacteremia (sepsis) are rare.
- Traumatic injuries. During military operations and terrorist acts, a lung abscess may form as a result of direct injury or injury to the chest.
The risk group includes people with diseases that increase the likelihood of purulent inflammation, for example, patients with diabetes mellitus. With bronchiectatic disease, there is a possibility of aspiration of infected sputum. With chronic alcoholism, aspiration with vomit is possible, the chemically aggressive environment of which can also provoke a lung abscess.
The initial stage is characterized by limited inflammatory infiltration of lung tissue. Then there is a purulent melting of the infiltrate from the center to the periphery, resulting in a cavity. Gradually, the infiltration around the cavity disappears, and the cavity itself is lined with granulation tissue, in the case of a favorable course of lung abscess, obliteration of the cavity occurs with the formation of a site of pneumosclerosis. If, as a result of the infectious process, a cavity with fibrous walls is formed, then the purulent process in it can self-sustain for an indefinitely long period of time (chronic lung abscess).
Classification of lung abscess
According to the etiology of lung abscesses, depending on the pathogen, they are classified into:
- caused by other pathogens.
The pathogenetic classification is based on how the infection occurred (bronchogenic, hematogenic, traumatic and other ways). According to the location in the lung tissue, abscesses are central and peripheral, in addition, they can be single and multiple, located in one lung or be bilateral. Some authors are of the opinion that lung gangrene is the next stage of an abscess. By origin, there are:
- Primary abscesses. Develop in the absence of background pathology in previously healthy individuals .
- Secondary abscesses. They are formed in people with immunosuppression (HIV-infected, who have undergone organ transplantation).
Symptoms of lung abscess
The disease occurs in two periods: the period of abscess formation and the period of opening the purulent cavity. During the formation of a purulent cavity, pain in the chest area is noted, which increases with breathing and coughing, fever, sometimes of the hectic type, dry cough, shortness of breath, fever. But in some cases, clinical manifestations may be poorly expressed, for example, with alcoholism, pain is practically not observed, and the temperature rarely rises to subfebrile.
With the development of the disease, the symptoms of intoxication increase: headache, loss of appetite, nausea, general weakness. The first period of lung abscess lasts on average 7-10 days, but a prolonged course of up to 2-3 weeks is possible, or vice versa, the development of the purulent cavity is rapid and then the second period of the disease begins after 2-3 days.
During the second period of lung abscess, the opening of the cavity and the outflow of purulent contents through the bronchus occur. Suddenly, against the background of fever, the cough becomes moist, and sputum is coughed up with a “full mouth”. Up to 1 liter or more of purulent sputum leaves per day, the amount of which depends on the volume of the cavity.
Symptoms of fever and intoxication after sputum discharge begin to decrease, the patient’s well-being improves, blood tests also confirm the extinction of the infectious process. But a clear separation between periods is not always observed, if the draining bronchus is small in diameter, then the discharge of sputum may be moderate.
If the cause of the lung abscess is putrefactive microflora, then due to the fetid smell of sputum, it is impossible for the patient to stay in the general ward. After standing in the container for a long time, sputum stratification occurs: the lower thick and dense layer of grayish color with a tiny tissue detritus, the middle layer consists of liquid purulent sputum and contains a large amount of saliva, and in the upper layers there is a foamy serous liquid.
If the pleural cavity and pleura are involved in the process, then the abscess is complicated by purulent pleurisy and pyopneumothorax, with purulent melting of the vessel walls, pulmonary bleeding occurs. It is also possible to spread the infection, with the defeat of a healthy lung and with the formation of multiple abscesses, and in the case of the spread of infection by hematogenic means – the formation of abscesses in other organs and tissues, that is, the generalization of infection and bacteremic shock. In about 20% of cases, an acute purulent process is transformed into a chronic one.
The examination is carried out by a pulmonologist. During visual examination, the part of the chest with the affected lung lags behind during breathing, or if the lung abscess is bilateral, the movement of the chest is asymmetric. To clarify the diagnosis, the following procedures are prescribed:
- Radiography of the lungs. It is the most reliable study for making a diagnosis, as well as for differentiating an abscess from other bronchopulmonary diseases.
- Other instrumental techniques. In complex diagnostic cases, CT or MRI of the lungs is performed. ECG, spirography and bronchoscopy are prescribed to confirm or exclude complications of lung abscess. If the development of pleurisy is suspected, a pleural puncture is performed.
- Sputum tests. A general sputum analysis is performed for the presence of elastic fibers, atypical cells, Mycobacterium tuberculosis, hematoidin and fatty acids. Bacterioscopy followed by sputum back-up is performed to identify the pathogen and determine its sensitivity to antibacterial drugs.
- General blood examination. There is pronounced leukocytosis in the blood, a rod-shaped shift of the leukocyte formula, toxic granularity of neutrophils, an increased level of ESR. In the second phase of the lung abscess, the tests gradually improve. If the process is chronicled, then the ESR level increases, but remains relatively stable, there are signs of anemia.
- Biochemical blood analysis. The biochemical parameters of the blood change – the amount of sialic acids, fibrin, seromucoid, haptoglobins and α2- and u-globulins increases; a decrease in albumins in the blood indicates the chronization of the process.
- Urine examination. In the general analysis of urine – cylindrical, microhematuria and albuminuria, the degree of severity of changes depends on the severity of the course of the lung abscess.
Treatment of lung abscess
The severity of the course of the disease determines the tactics of its therapy. Both surgical and conservative treatment is possible. In any case, it is carried out in a hospital, in a specialized department of pulmonology. Conservative therapy includes bed rest, giving the patient a draining position several times a day for 10-30 minutes to improve the outflow of sputum.
Antibacterial therapy is prescribed immediately, after determining the sensitivity of microorganisms, correction of antibiotic therapy is possible. To reactivate the immune system, autohemotransfusion and transfusion of blood components are performed. Antistaphylacoccal and gamma globulin are prescribed according to indications. If natural drainage is not enough, then bronchoscopy is performed with active aspiration of cavities and with washing them with antiseptic solutions (bronchoalveolar lavage).
It is also possible to administer antibiotics directly into the cavity of the lung abscess. If the abscess is located peripherally and has a large size, then transthoracic puncture is resorted to. When conservative treatment of lung abscess is ineffective, as well as in cases of complications, lung resection is indicated.
Prognosis and prevention
The favorable course of the lung abscess goes with the gradual resorption of infiltration around the purulent cavity; the cavity loses its regular rounded outlines and ceases to be defined. If the process does not take a protracted or complicated nature, then recovery occurs in 6-8 weeks. The mortality rate in lung abscess is quite high and today is 5-10%.
There is no specific prevention of lung abscess. Non-specific prevention is timely treatment of pneumonia and bronchitis, rehabilitation of foci of chronic infection and prevention of aspiration of the respiratory tract. The fight against alcoholism is also an important aspect in reducing the incidence rate.