A 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 – a cough with profuse discharge of purulent sputum. The diagnosis is made on the basis of a combination of clinical, laboratory data, X-ray pictures. Treatment involves massive antimicrobial therapy, infusion-transfusion therapy, a series of sanitation bronchoscopies. Surgical management may include draining the abscess or resecting the lungs.
Lung abscess is included in the group of ” infectious lung destruction “, 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 of a smoker. More than half of the abscesses form 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.
Staphylococcus aureus, gram-negative aerobic bacteria, and non-spore-forming anaerobic organisms are the most common causes of lung abscess. Pathogens most often penetrate the lung cavity by the 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 of vomit, for example, in an unconscious state or in a state of alcoholic intoxication, the ingress of foreign bodies can also cause a lung abscess.
- Damage to the vessels of the lungs . Secondary bronchogenic infection is possible with pulmonary infarction, which occurs due to embolism of one of the branches of the pulmonary artery.
- Sepsis . Variants of hematogenous infection, when the infection enters the pulmonary capillaries during bacteremia (sepsis), are rare.
- Traumatic injury . During hostilities and terrorist attacks, a lung abscess can form as a result of direct injury or injury to the chest.
The risk group includes people with diseases in which the likelihood of purulent inflammation increases, for example, patients with diabetes mellitus. With bronchiectasis, the likelihood of aspiration of infected sputum appears. In 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 the lung tissue. Then there is a purulent fusion 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 case of a favorable course of the lung abscess, the cavity is obliterated with the formation of a pneumosclerosis site. 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).
According to the etiology, lung abscesses are classified, depending on the pathogen, into:
- caused by other pathogens.
The pathogenetic classification is based on how the infection occurred (bronchogenic, hematogenous, traumatic and other ways). By 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 . They develop in the absence of background pathology in previously healthy individuals.
- Secondary abscesses . Formed in persons with immunosuppression (HIV-infected who have undergone organ transplantation).
Lung abscess symptoms
The disease occurs in two periods: the period of the formation of an abscess and the period of opening the purulent cavity. During the period of formation of a purulent cavity, pain in the chest area is noted, aggravated by breathing and coughing, fever, sometimes hectic type, dry cough, shortness of breath, fever. But in some cases, clinical manifestations can be mild, for example, with alcoholism, pain is practically not observed, and the temperature rarely rises to subfebrile.
With the development of the disease, intoxication symptoms 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 a purulent cavity is rapid and then after 2-3 days the second period of the disease begins.
During the second period of the lung abscess, the cavity is opened and the purulent contents outflow through the bronchus. Suddenly, against the background of fever, the cough becomes moist, and sputum is coughing 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 sputum discharge may be moderate.
If the cause of a lung abscess is putrid microflora, then due to the fetid odor of sputum , the patient’s stay in the general ward is impossible. After a long standing in the container, sputum stratification occurs: the lower thick and dense layer of grayish color with tiny tissue detritus, the middle layer consists of liquid purulent sputum and contains a large amount of saliva, and the upper layers contain a frothy serous fluid.
If the pleural cavity and pleura are involved in the process, then the abscess is complicated by purulent pleurisy and pyopneumothorax, with purulent fusion of the vessel walls, pulmonary bleeding occurs. It is also possible to spread the infection, with damage to a healthy lung and with the formation of multiple abscesses, and in the case of the spread of infection by hematogenous pathway, the formation of abscesses in other organs and tissues, that is, generalization of the 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. On visual inspection, 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 the diagnosis, as well as for the differentiation of an abscess from other bronchopulmonary diseases.
- Other instrumental techniques . In difficult diagnostic cases, CT or MRI of the lungs is performed . ECG, spirography and bronchoscopy are prescribed to confirm or rule out complications of a lung abscess. If pleurisy is suspected, pleural puncture is performed .
- Sputum tests . A general analysis of sputum is performed for the presence of elastic fibers, atypical cells, mycobacterium tuberculosis, hematoidin and fatty acids. Bacterioscopy followed by sputum bacterial culture is performed to identify the pathogen and determine its sensitivity to antibacterial drugs.
- General blood test . In the blood, a pronounced leukocytosis, a stab shift in the leukocyte formula, toxic granularity of neutrophils, an increased level of ESR. In the second phase of the lung abscess, the analyzes gradually improve. If the process is chronic, then the level of ESR increases, but remains relatively stable, there are signs of anemia.
- Biochemical blood test . Blood biochemical parameters change – the amount of sialic acids, fibrin, seromucoid, haptoglobins and α2- and γ-globulins increases; the chronization of the process is indicated by a decrease in albumin in the blood.
- Urine examination . In the general analysis of urine – cylindruria , microhematuria and albuminuria, the severity of the changes depends on the severity of the lung abscess.
Lung abscess treatment
The severity of the course of the disease determines the tactics of its therapy. Both surgical and conservative treatment are possible. In any case, it is carried out in a hospital, in a specialized department of pulmonology. Conservative therapy includes adherence to bed rest, giving the patient a draining position several times a day for 10-30 minutes to improve sputum outflow.
Antibiotic 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. Antistaphylococcal and gamma globulin are prescribed according to indications. If natural drainage is not enough, then bronchoscopy is performed with active aspiration of the cavities and rinsing 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 is large, then transthoracic puncture is used. When conservative treatment of a lung abscess is ineffective, as well as in cases of complications, resection of the lung is indicated .
Forecast and prevention
The favorable course of a lung abscess goes with a gradual resorption of the infiltration around the purulent cavity; the cavity loses its regular rounded shape and ceases to be defined. If the process does not take on a protracted or complicated nature, then recovery occurs in 6-8 weeks. Mortality with lung abscess is quite high and today it is 5-10%.
There is no specific prevention of lung abscess. Non-specific prophylaxis is timely treatment of pneumonia and bronchitis, sanitation of foci of chronic infection and prevention of airway aspiration. Another important aspect in reducing the incidence rate is the fight against alcoholism.