Chronic obstructive pulmonary disease
Definition

Many definitions of COPD in the past included chronic bronchitis and emphysema but these have never been included in GOLD report definitions. Emphysema is defined as enlarged airspaces (alveoli) whose walls break down resulting in permanent damage to the lung tissue and is just one of the structural abnormalities that can limit airflow. The condition can exist without airflow limitation but commonly it does. Chronic bronchitis is defined as a productive cough that is present for at least three months each year for two years but does not always result in airflow limitation although the risk of developing COPD is great. These older definitions grouped the two types as type A and type B. Type A were emphysema types known as pink puffers due to their pink complexion, fast breathing rate and pursed lips. Type B were chronic bronchitic types referred to as blue bloaters due to low oxygen levels causing a bluish color to the skin and lips and swollen ankles. These differences were suggested to be due to the presence or not of collateral ventilation, evident in emphysema and lacking in chronic bronchitis. This terminology was no longer accepted as useful, as most people with COPD have a combination of both emphysema and airway disease. These are now recognized as the two major phenotypes of COPD — emphysematous phenotype and chronic bronchitic phenotype.
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