Article Figures & Data
Figures
- Figure 1.
The pathophysiological components of obstructive airway diseases including asthma, chronic obstructive pulmonary disease, and their overlap. Chronic airway inflammation is the central component of all obstructive lung diseases, whereas airway obstruction (AO) and airway hyperreactivity (AHR) are important features. AHR can result in bronchospasm (“dynamic” AO), whereas airway edema, mucus plugs, and airway remodeling can cause a “static” or “stuctural” AO.
- Figure 2.
The classic Venn diagram used to describe the overlap of the pathologic and clinical features of chronic bronchitis, emphysema, and asthma. The subsets comprising chronic obstructive pulmonary disease (COPD) are shaded. Chronic bronchitis, emphysema, and airway obstruction are independent effects of cigarette smoking and may occur in various combinations. Patients with chronic bronchitis, emphysema, or both are not considered to have COPD unless they have airflow obstruction. Patients with asthma whose airflow obstruction is completely reversible do not have COPD, whereas those who develop a partially reversible airflow obstruction over time are considered to have asthma-COPD overlap syndrome (“asthma with a COPD component” or “COPD with asthmatic features”). Modified with permission from the American Thoracic Society.21
Tables
- Table 1. Characteristic Similarities and Differences Between Asthma, Chronic Obstructive Pulmonary Disease (COPD), and the Overlap Syndrome
Asthma COPD Overlap Syndrome Pathology Chronic airway inflammation, typically eosinophilic and driven by CD4 cells. Neutrophilic inflammation has been observed in the airways of some asthmatics and is associated with increased steroid resistance. Chronic airway inflammation, typically neutrophilic and driven by CD8 cells. Eosinophilic inflammation has been observed in the airways of some patients with COPD and is associated with greater steroid sensitivity. Pathologic overlap in the inflammatory profiles of both asthma and COPD, particularly among the elderly. Pathophysiology Reversible airway obstruction; progressive deterioration over time is uncommon. Partially reversible airway obstruction; progressive deterioration overtime is typical. Functional overlap between asthma and COPD, particularly among the elderly. Treatment of acute exacerbations Systemic corticosteroids & inhaled bronchodilators Improve symptoms and lung function and decrease the length of hospital stay. Improve symptoms and lung function and decrease the length of hospital stay. No data available. Maintenance treatment of stable disease ICSs The mainstay of treatment in patients with persistent asthma. Less effective response. ICSs are recommended for patients with more severe COPD (FEV1 <50% of predicted) whose symptoms are not optimally controlled with inhaled bronchodilators. No data available. ICS monotherapy is not recommended. Inhaled bronchodilators Inhaled short-acting β2-agonists are the mainstay of treatment for intermittent asthma. The mainstay of treatment in patients with COPD; inhaled anticholinergics may be more effective than inhaled β2-agonists as monotherapy in COPD. No data available. Inhaled long-acting β2-agonists monotherapy is not recommended. FEV1, forced expiratory volume in 1 second; ICS, inhaled corticosteroid.
