Emphysema and chronic bronchitis are airflow-limited states contained within the disease state known as chronic obstructive pulmonary disease (COPD). Just as asthma is no longer grouped with COPD, the current definition of COPD put forth by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) also no longer distinguishes between emphysema and chronic bronchitis.[1]
Emphysema is pathologically defined as an abnormal permanent enlargement of air spaces distal to the terminal bronchioles, accompanied by the destruction of alveolar walls and without obvious fibrosis. Clinically, the term emphysema is used interchangeably with chronic obstructive pulmonary disease, or COPD.