Previous terms for the condition: chronic bronchitis, emphysema
Diagnostic features:
(1) Airflow obstruction as defined by changes in pulmonary function testing (see below).
(2) The airflow obstruction is caused by a combination of damage to both the airways and to the lung parenchyma.
(3) The condition is usually progressive. It is not fully reversible.
(4) The condition can result in physical disability and a poor quality of life.
Criteria for airflow obstruction on pulmonary function testing (PFT):
(1) forced expiratory volume in 1 second (FEV1) < 80% of the value predicted based on age, gender and race
(2) ratio of FEV1 to FVC (forced vital capacity) < 0.7
The changes are different from those seen in asthma. Both asthma and COPD may coexist in the same patient.
Conditions associated with COPD:
(1) Tobacco smoking is the usual cause for COPD.
(2) Occupational and other exposures may contribute to development of COPD.
(3) Alpha-1-antitrypsin deficiency may predispose a patient to its development.
