支气管扩张是一种慢性肺部疾病，其中最常见的一种类型，由于支气管及其周围肺组织的慢性炎症损坏气道壁，导致支气管组织结构较正常的管腔扩大及变形，引起反复发作的咳嗽气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气喘气