In the latter, in addition to the above symptoms, there are dyspnea and wheezing, indicating that the spasm of the smooth muscles of bronchi and bronchioli is an important pathogenetic factor.

• 前者以咳嗽；咳痰为主要表现；后者还加上喘息症状；并常闻及哮鸣音；提示支气管和细支气管平滑肌痉挛是发病主因.；慢性支气管炎是由于支气管感染；物理和化学因素刺激或过敏所致的慢性支气管炎症