structural:expansion, linguistic:voice_change
Differential diagnosis

COPD may need to be differentiated from other conditions such as congestive heart failure, asthma, bronchiectasis, tuberculosis, obliterative bronchiolitis and diffuse panbronchiolitis. The distinction between asthma and COPD is made on the basis of the symptoms, smoking history and whether airflow limitation is reversible with bronchodilators at spirometry. Chronic bronchitis with normal airflow is not classified as COPD.