Which of the following is a major characteristic of COPD?

A major characteristic of Chronic Obstructive Pulmonary Disease (COPD) is that it encompasses two primary conditions: emphysema and chronic bronchitis. Both of these conditions are progressive lung diseases that lead to increased difficulty in breathing and a decline in lung function over time.

Emphysema involves the damage and enlargement of air sacs (alveoli) in the lungs, reducing the surface area for gas exchange, while chronic bronchitis is characterized by persistent inflammation of the airways, leading to mucus production and obstruction of airflow. The inclusion of both conditions under the COPD umbrella illustrates the spectrum of disease severity and symptoms, which vary among individuals but contribute to the overall obstructive nature of the disease.

Recognizing this characteristic is vital in understanding COPD's impact on patients, as it emphasizes the chronic and degenerative aspects of the disease rather than viewing it as an acute or solely reversible condition.