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What causes acute bronchitis in children?
Last reviewed: 19.10.2021
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Factors contributing to the occurrence of bronchitis:
- endogenous-constitutional (lymphatic constitution, allergy);
- changes in the immunological status - a decrease in IgA, IgG;
- age anatomical and physiological features of respiratory organs in children - imperfection of protective barriers, propensity for exudation, imperfection of functions;
- concomitant diseases (hypotrophy, rickets, anemia, polyhypovitaminosis);
- exogenous influences - cooling, air allergens, atmospheric fluctuations, parents' smoking, air pollution (mechanical or chemical irritations of the mucous membrane with dust of mineral or vegetable origin, gases).
Causes of acute bronchitis. Etiological factors of acute simple bronchitis are viruses (parainfluenza type I and II, PC viruses, adenoviruses, influenza viruses, cytomegalovirus). It is possible to activate and move from the nasopharynx of the autoflora under the influence of physical and chemical factors, supercooling. In most cases, the etiology of acute simple bronchitis is confirmed by viral-bacterial associations in which viruses that have a tropism to the epithelium of the respiratory tract, damage it, reduce the barrier properties of the bronchial wall and create the conditions for the development of a bacterial inflammatory process. Most often it is not about invasive, but intralaminar reproduction of opportunistic bacterial autoflora. Bronchitis, as a rule, occurs during the course of childhood infections such as whooping cough and measles. In older children, a frequent etiologic factor may be Mycoplasma pneumoniae, Chlamydia pneumoniae.
Pathogenesis of acute bronchitis . Infectious inflammation of the bronchial mucosa leads to hypersecretion and changes in the physicochemical properties (viscosity, elasticity, adhesion) of mucus, which changes its fluidity and hinders the work of the ciliary cells, leads to the violation of mucociliary clearance, the most important mechanism that ensures the sanitation of the respiratory tract. Cough pushes, arising from irritation of the afferent receptors of the vagus nerve, enhance the clearing function of the bronchi. When coughing, excess mucus is removed at a pressure of 300 mm Hg. Art. With an air speed of 5-6 l / s.