Their antiinflammatory effect is the chief reason why
glucocorticoids are used in pneumology. By diminishing capillary permeability,
glucocorticoids slow passage of fluids and cells towards locations of
inflammation. As they promote recirculation of polymorphonuclear neutrophils and conversely decrease eosinophil, basophil, lymphocyte and monocyte blood counts, cellular reaction is curtailed. Lastly,
glucocorticoids antagonize release of
enzymes and mediators by inflammatory cells and have an immunosuppressive action which predominates on T cells. In
asthma, in addition to their anti-
edema effect, they potentiate or restore the action of
bronchodilators. Parenteral administration of
glucocorticoids is mainly indicated in emergency settings; oral
glucocorticoids are used in maintenance
therapy which relies chiefly on short half-life derivatives (
prednisone,
prednisolone,
methylprednisolone) whose suppressive effect on the hypothalamo-pituitary axis is less than that of intermediary or long half-life
corticosteroids. Lastly,
aerosol forms have a chiefly preventive action and require that the respiratory tract be clear to be efficient. Main indications of
glucocorticoids are those conditions in which immunologic and/or inflammatory reactions have a deleterious effect: in
asthma, combined with
bronchodilators,
glucocorticoids are the mainspring of management of severe attacks and protracted, severe
asthma;
corticosteroid aerosols have the advantage that systemic
corticosteroid therapy can be avoided or shortened, thereby lessening the risk/benefit ratio;
extrinsic allergic alveolitis,
sarcoidosis with multiple localizations, and/or respiratory impairment, and protracted
pulmonary eosinophilia, are choice indications for systemic
corticosteroid therapy;
glucocorticoids may be insufficiently effective in
idiopathic pulmonary fibrosis or respiratory localizations of
vasculitis, which may justify association of
immunosuppressants; indications of
glucocorticoids in certain forms of
tuberculosis or
cancer of the respiratory tract are less clearly systematized.(ABSTRACT TRUNCATED AT 250 WORDS)