Bronchitis: Causes

Pathogenesis (development of disease)

Acute bronchitis is a viral infection in more than 90% of cases. The disease is most commonly caused in children by RS viruses (5%), adenoviruses 5%), coxsackie viruses, and ECHO viruses, and in adults most commonly by rhino viruses (30-50%), coronaviruses (10-15%), influenza viruses (5-15%), and parainfluenza viruses (5%), as well as SARS coronavirus (extremely rare). Bacteria are rarely the primary triggers (<10%) – more commonly as bacterial superinfection: H. influenzae and S. pneumoniae. In young adults, Mycoplasma pneumoniae is the primary causative agent.In immunocompromised patients, acute bronchitis may also be caused by fungal infections. In addition to infectious causes, bronchitis may also be due to allergic or toxic factors. Another possible cause is heart failure (cardiac insufficiency) – in such a case there is a so-called congestive bronchitis. Chronic bronchitis is mainly caused by smoking.

In bronchitis, there is inflammation of the bronchial mucosa with subsequent loss of ciliated epithelium and possible remodeling of the lining epithelium, and thus the risk of descending infection.

Etiology (Causes)

Biographic causes

  • Genetic burden – such as “congenital bronchial hyperresponsiveness” (exaggerated airway responsiveness to an exogenous stimulus (e.g., cold air, inhalation toxins) leading to pathologic airway narrowing (bronchoobstruction))
  • Rare hereditary defects such as IgA deficiency (most common immunodeficiency: 1: 500 to 1: 700).
  • Age – increasing age
  • Occupations – cooks have 2.5 times higher risk of chronic bronchitis

Behavioral causes

  • Nutrition
    • Micronutrient deficiency (vital substances) – see Prevention with micronutrients.
  • Consumption of stimulants
    • Tobacco (smoking, passive smoking)
  • Lack of hygiene during periods of epidemic occurrence (temporal and local accumulation of a disease) of respiratory infections.

Causes related to disease

  • Respiratory infections
  • Bronchial stenosis (narrowing)
  • Heart failure (cardiac insufficiency)
  • Pleural rash – thickened, poorly mobile lung pleura.
  • Diaphragmatic paresis – paralysis of the diaphragm – main respiratory muscle.

Environmental pollution – intoxications (poisonings).

  • Air pollutants: particulate matter, ozone, sulfur dioxide.