慢性支气管炎通常经过三个阶段:①单纯慢性支气管炎,在此阶段粘液状支气管分泌物量反复增加足以引起咳痰;②慢性或复发性粘液脓性支气管炎,此时由于肺部有肺炎链球菌和嗜血流感杆菌继发感染,痰液持续或间歇呈脓性;③慢性阻塞性支气管炎,此时肺内气道有持续广泛的狭窄,至少在呼气时有此现象,它可引起气流阻力增加。这一阶段患者几乎总有一定程度的肺气肿。咳嗽吐痰不一定会发展到呼吸机能损害。而且,有些患者常在呼吸道感染后即发生气道阻塞,而无长期咳痰的历史。部分患者(特别是痰液嗜酸粒细胞明显增多的患者)实际上是罹患内源性哮喘,口服及/或气溶胶吸入皮质类固醇对此症常有良效。导致支气管炎发生和发展的重要因素有吸烟、大气污染(主要是由于烟雾和二氧化硫)、接触粉尘的职业和感染。偶见患者血液中缺乏α_1抗胰蛋白酶,但甚至在这些病例中也常有吸烟的刺激。吸烟量越 Chronic bronchitis usually after three stages: ① chronic bronchitis, mucus-like bronchial secretions at this stage the amount of repeated increase enough to cause sputum; ② chronic or recurrent mucopurulent bronchitis, this time as the lungs Streptococcus pneumoniae And the second episode of infection with H. influenzae bacilli, sputum continuous or intermittent was purulent; ③ chronic obstructive bronchitis, when the airways in the lungs have continued extensive stenosis, at least in the exhalation of this phenomenon, it can cause Air flow resistance increases. There is almost always a certain degree of emphysema in this stage of the patient. Cough and spit may not develop to respiratory function damage. Moreover, some patients often have a history of airway obstruction after a respiratory infection without long-term expectoration. Some patients, especially those with a marked increase in sputum eosinophilia, are actually suffering from endogenous asthma, and oral and / or aerosol inhaled corticosteroids often have a beneficial effect on this condition. Important factors that contribute to the occurrence and development of bronchitis are smoking, air pollution (mainly due to smoke and sulfur dioxide), occupational exposure to dust and infections. Occasionally, there is a lack of α_1 antitrypsin in the blood of the patient, but smoking is often stimulated even in these cases. Smoking more