Chronic bronchitis and emphysema (chronic obstructive pulmonary disease [COPD]) represent a major health problem in this country. Corticosteroids have provided an important advance in the management of bronchial asthma, but the role of these drugs in the therapy for COPD has not been defined clearly. To gain further insight into this problem, an overview of the pharmacologic properties and mechanisms of action of corticosteroids on the cellular systems of the lung and a critical analysis of the 17 studies evaluating the efficacy of therapy with corticosteroids in COPD were done. There are several theoretic reasons why corticosteroids might be useful in treating COPD; however the majority of studies have not demonstrated a positive effect, yet individual patients have attained marked improvement. An objectively monitored, finite trial of therapy with corticosteroids in the patient with COPD who has worsening symptoms is warranted, as the benefit is high in responsive individuals and the risk is low in nonresponders.

Abnormalities in small airways appear to be important in the evolution of chronic obstructive pulmonary disease. Patients with these pathologic lesions may have normal values for airway resistance and forced expiratory volume in one second. Two new tests, the closing volume (CV) and the dependence of maximal flow on density, are believed to be sensitive to abnormalities in the peripheral airways. The CV test detects an increased nonuniformity of changes in volume of pulmonary units. Reduced dependence of flow on density is believed to result from an increase in the peripheral component of the losses of driving pressure which determine maximal expiratory flow. Both tests differentiate smokers with normal conventional spirometric data from age-matched nonsmokers. Although this evidence suggests that these tests can be used to detect abnormalities in small airways, there is very little pathologic confirmation of this belief. The clinical significance of abnormalities in the results of either of these tests in an otherwise normal person has not yet been determined.

Fiberglass inhalation seems to produce a minimal tissue response in the lungs, and the reaction is one of macrophagic mobilization and is characteristic of the pulmonary response to those nonfibrogenic dusts classified as nuisance dusts. In order to merit the designation of a nuisance dust, the pulmonary response must fulfill the following three requisites:31(p5) (1) The alveolar architecture must remain intact. (2) The stromal proliferation is minimal and consists mainly of reticulin. (3) The tissue reaction is potentially reversible. Inasmuch as the pulmonary reaction to the dusts of fiber glass fulfills all of these requirements, it should be classified as a nuisance dust. 31(p5) There is no evidence to indicate that inhaling fiber glass is associated with either permanent respiratory impairment or carcinogenesis; however, the final verdict as far as the latter is concerned must await the findings of long-term mortality studies.