[Physiopathologic mechanisms of drug-induced lung diseases in man]

Iatrogenic lung disease in man is generated by very different and often complex pathology. This explains the great clinical diversity of these disorders which may manifest as eosinophilic pneumonia, intra-alveolar haemorrhage, bronchiolitis obliterans and diffuse interstitial pneumonia even with pulmonary fibrosis. The causes are also very varied such as direct cellular toxicity, cellular oedema, an alteration of the alveolar capillary membrane, the activation of inflammatory and/or immune cells, which are responsible for the production of soluble mediators whose effects are sometimes harmful to the pulmonary parenchyma. Rather than reporting on the different clinical types of iatrogenic lung disease and indicating for each one the hypothetical or known physiopathogenic mechanism, we have chosen to examine certain fundamental lesional mechanisms and to indicate the principal nosological groups which they cover. We have centered this review on the physiopathogenic models which are the most coherent and most fully elaborated based on observations made on man or on experimental animal models. Among those we have reported here is a case of bleomycin toxicity, with its direct toxic mechanism on the epithelial or endothelial cellular targets, amiodarone lung disease and with its associated alveolar oedema, inflammatory reactions and immunological reactions whose specificity is poorly understood; also there are some alveolitides whose specificity has been demonstrated, such as those to minocycline and to BCG and finally a complex model which is both inflammatory and disturbed immunology in radiation pneumonia.