[Glucocorticoids in pneumology]

Abstract

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)