ABSTRACT
Reactive airways disease (RAWD) is generally defined on a functional basis as either a significant reversibility of airway obstruction in response to broncho dilators or, alternatively, as bronchial hyperresponsiveness (BHR) to nonspecific agents such as methacholine, histamine, cold air, or exercise. Both of these characteristics have been described with COPD, although it may simply be a reflection of reduced airway diameter (1-3). Asthma is characterized by revers ibility and BHR even when airway mechanics are normal or nearly so. Clearly, the mechanisms for this responsive and acutely changing condition are quite distinct
from the chronic changes associated with chronic bronchitis, and irreversible changes of emphysema. Asthma has been characterized as having a mild long term course without development of chronic bronchitis or emphysema (4,5), but others have suggested that BHR may correlate with the development of COPD even in patients without alA T deficiency (6,7).
