Infectious destruction of the lungs: causes, symptoms, diagnosis, treatment

Infectious lung destruction - severe pathological conditions characterized by inflammatory infiltration and subsequent purulent or putrefactive decay (destruction) of lung tissue as a result of exposure to nonspecific infectious agents (NV Pukhov, 1998). There are three forms of infectious destruction of the lungs: abscess, gangrene and gangrenous abscess of the lung.

Causes of infectious lung destruction

Specific pathogens infectious destruction of the lungs does not exist. In 60-65% of patients, the cause of the disease is nonporogenous obligatory anaerobic microorganisms: bacteroides (B. Fragilis, B. Melaninogenicus); Fusobacteria (F.nucleatum, F.necropharum); anaerobic cocci (Peptococcus, Peptostreptococcus), etc. Infectious destructions resulting from aspiration of the oropharyngeal mucus are more often caused by fusobacteria, anaerobic cocci and B.melaninogenicus. When aspiration of gastric contents, the most common causative agent of infectious lung destruction is B. Fragilis.

In 30-40% of patients, infectious lung destruction is caused by golden staphylococcus, streptococcus, Klebsiella, proteus, Pseudomonas aeruginosa, enterobacteria. These pathogens most often cause infectious destruction of the lungs, primarily not associated with aspiration of the oropharyngeal mucus or gastric contents.

Infectious destruction of the lungs of hematogenous-embolic origin is most often caused by Staphylococcus aureus.

In rare cases, the cause of the disease are non-bacterial pathogens (fungi, protozoa).

Predisposing factors: smoking, chronic bronchitis, bronchial asthma, diabetes mellitus, epidemic influenza, alcoholism, maxillofacial trauma, prolonged exposure to cold, influenza.

Pathogenesis of infectious lung destruction

Pathogens infectious destruction of the lungs penetrate the pulmonary parenchyma through the respiratory tract, less often hematogenously, lymphogenically, by spreading from neighboring organs and tissues. With transbronchial infection, the source of microflora is the oral cavity and nasopharynx. An important role is played by aspiration (microaspiration) of infected mucus and saliva from the nasopharynx, as well as gastric contents. In addition, lung abscesses can occur with closed injuries (bruises, compression, tremors) and penetrating injuries of the chest. With an abscess initially observed a limited inflammatory infiltration with purulent melting of the lung tissue and the formation of a decay cavity, surrounded by a granulation shaft.

Subsequently (after 2-3 weeks), a breakthrough of the purulent focus in the bronchus occurs; with a good drainage of the cavity walls collapse with the formation of a scar or a site of pneumosclerosis.

With gangrene of the lung after a short period of inflammatory infiltration, due to the influence of the products of vital activity of the microflora and thrombosis of the vessels, extensive necrosis of the lung tissue develops without clear boundaries. Necrotized tissue forms a number of foci of decay, which are partially drained through the bronchus.

The most important pathogenetic factor is also a decrease in the function of general immunity and local bronchopulmonary protection (see " Chronic bronchitis ").

Classification of infectious lung destruction

1. Causes (depending on the type of infectious agent).
   • Aerobic and / or conditionally anaerobic flora.
   • Obligatno anaerobic flora.
   • Mixed aerobic-anaerobic flora.
   • Non-bacterial pathogens (fungi, protozoa).
2. Pathogenesis (mechanism of infection).
   • Bronchogenic, including aspiration, post-pneumonic, obturator.
   • Hematogenic, including embolic.
   • Traumatic.
   • Associated with the immediate passage of suppuration from neighboring organs and tissues.
3. Clinical and morphological form.
   • Abscesses purulent.
   • Abscesses gangrenous.
   • Gangrene lung.
4. Location within the lung.
   • Peripheral.
   • The central ones.
5. Prevalence of the pathological process.
   • Single.
   • Multiple.
   • One-sided.
   • Two-sided.
   • With the defeat of the segment.
   • With the defeat of the share.
   • With the defeat of more than one share.
6. The severity of the current.
   • Easy flow.
   • The course of medium gravity.
   • Heavy current.
   • Extremely heavy current.
7. Presence or absence of complications.
   • Uncomplicated.
   • Complicated:
     • pyopneumovorax, pleural empyema;
     • pulmonary hemorrhage;
     • bacteremia shock;
     • acute respiratory distress syndrome of adults;
     • sepsis (septicopyemia);
     • phlegmon of thoracic wall;
     • defeat of the opposite side in a primarily unilateral process;
     • other complications.
8. The nature of the current (depending on the time criteria).
   • Sharp.
   • With a subacute current.
   • Chronic abscesses of the lungs (chronic gangrene is not possible).

Note: gangrenous abscess is an intermediate form of infectious lung destruction, which is less extensive and more prone to delimitation than gangrene, necrosis of pulmonary tissue. At the same time during the melting of lung tissue, a cavity is formed with parietal or loosely lying tissue sequesters.

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