Focal pneumonia occurs after bronchitis, with various infectious diseases (measles, whooping cough, flu, typhoid fever), kidney diseases, circulatory disorders, gas poisoning (phosgene, etc. ), in case of ingestion of infectious or toxic material during anesthesia, on the basis of lung collapse (atelectasis), stagnation, in bedridden patients. Focal pneumonia occurs when a blood stream infects the lungs (metastatic pneumonia).
The infection enters the lungs bronchogenic, hematogenous and lymphogenous. When inhaled, microorganisms with a stream of air penetrate the bronchi. With normal excitability of the bronchial mucosa, the cilia of the epithelial layer are captured and thrown back with a cough or absorbed by phagocytes.
When inflammatory processes, as well as in case of hypo- and vitamin deficiency A, when the epithelium lining the airways atrophies, the ciliary barrier function is lost and microorganisms settle on the bronchial walls, cause their inflammation with the process spreading to the pulmonary parenchyma.
Focal pneumonia often occurs as a result of getting into the bronchi, due to a decreased reflex excitability of the latter, foreign substances - food, vomit, pus, blood, mucus. This is observed with hemorrhage in the brain, a wound in the chest, face, jaw, while intoxication, paralysis of the swallowing muscles. In these cases, the development of pneumonia is caused by obstruction of the bronchi with foreign substances, the occurrence of lung atelectasis. Air is drawn in from the electrostatic sites and favorable conditions are created for the onset of the inflammatory process.
Similar conditions for the development of pneumonia occur in people who are bedridden for a long time, weakened patients, with circulatory disorders in the small circle, bronchiectatic disease, bronchial asthma , as a result of poor ventilation of the lungs and the formation of atelectatic sites in the lungs because of this.
Focal pneumonia can also develop in the hematogenous way as a result of infection by blood flow in ribronhialnuyu tissue, bronchi and alveoli. Hematogenous pneumonia occurs in septic diseases, infected wounds, operations in the abdominal cavity, in particular with an infected lesion in case of peptic ulcer, uterine diseases, when pathogens enter the lungs by hematogenous route and can cause metastatic pneumonia.
Inflammatory foci more often located in the lower lobes in one or both lungs, in various quantities and in different phases of development. In the inflamed areas of the alveoli contain a purulent, putrefactive fluid, but more often a serous fluid.