difference between asthma, copd, emphysema on PFT


  • normal spirometry, abnormal methacholine challenge, and then response to albuterol: asthma
  • baseline obstruction, near normalization after bronchodilator: asthma
  • baseline obstruction, no significant change after bronchodilator: COPD
  • normal spirometry, CT showing emphysema: emphysema1

Patients with asthma may develop increased compliance of the lungs consistent with emphysema despite the absence of a history of smoking. These patients are among the group classified as having the asthma-COPD overlap syndrome. Abbreviation: TLC, total lung capacity.2 3

Footnotes

  1. An Algorithmic Approach to Chronic Dyspnea

  2. SEEK Questionnaires

  3. Gelb AF, Yamamoto A, Verbeken EK, et al. Unraveling the pathophysiology of the asthma-COPD overlap syndrome: unsuspected mild centrilobular emphysema is responsible for loss of lung elastic recoil in never smokers with asthma with persistent expiratory airflow limitation. Chest. 2015;148(2):313-320.