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What causes acute bronchitis in children?
Last reviewed: 04.07.2025
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Factors that contribute to the development of bronchitis:
- endogenous-constitutional (lymphatic constitution, allergy);
- changes in immunological status - decrease in IgA, IgG;
- age-related anatomical and physiological characteristics of the respiratory organs in children - imperfection of protective barriers, tendency to exudation, imperfection of functions;
- concomitant diseases (malnutrition, rickets, anemia, polyhypovitaminosis);
- exogenous influences - cooling, airborne allergens, atmospheric fluctuations, parental smoking, air pollution (mechanical or chemical irritation of the mucous membrane by dust of mineral or plant origin, gases).
Causes of acute bronchitis. Etiological factors of acute simple bronchitis are viruses (parainfluenza types I and II, PC viruses, adenoviruses, influenza viruses, cytomegalovirus). Activation and movement of autoflora from the nasopharynx is possible under the influence of physicochemical factors, hypothermia. In most cases, viral-bacterial associations are confirmed in the etiology of acute simple bronchitis, in which viruses that have tropism for the epithelium of the respiratory tract damage it, reduce the barrier properties of the bronchial wall and create conditions for the development of a bacterial inflammatory process. Most often, we are talking not about invasive, but intralaminar reproduction of opportunistic bacterial autoflora. Bronchitis, as a rule, occurs during the course of such childhood infections as whooping cough and measles. In older children, a frequent etiological 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 complicates the work of the cilia of the ciliary cells, leading to a violation of mucociliary clearance - the most important mechanism that ensures the sanitation of the respiratory tract. Cough impulses, arising due to irritation of the afferent receptors of the vagus nerve, enhance the cleansing function of the bronchi. When coughing, excess mucus is removed under a pressure of 300 mm Hg with an air flow rate of 5-6 l/s.