What is bronchiectasis? Bronchiectasis is a chronic purulent disease in which the lumen of the bronchial tubes in the lungs is permanently and irreducibly dilated with fibrous thickening of the walls. The clinical manifestations are chronic cough, large amount of pus sputum or recurrent hemoptysis and other symptoms. 1, etiology 1, infection: infection is the most common cause of bronchiectasis such as chronic bronchitis, measles and pertussis after bronchopneumonia, tuberculosis, etc. 2, bronchial obstruction: tumor, enlarged lymph node compression and bronchial foreign body inhalation can make bronchial incomplete obstruction. 3, a few are related to congenital dysplasia. Second, the pathogenesis of repeated infections of the respiratory tract caused by chronic purulent inflammation of the bronchial tube wall, damage to the important support structures of the bronchial wall (such as smooth muscle, collagen fibers, elastic fibers and cartilage), so that it can not withstand inspiration and coughing on the lumen outward pull and expansion, while incomplete obstruction to form the role of live valve, so that the gas in the bronchial lumen below the obstruction is easy to inhale, not easy to exhale, the bronchial lumen The gas pressure in the bronchial lumen increases continuously, which promotes the persistent expansion of the bronchus.