[Pulmonary toxicity of drugs and thoracic irradiation in children].

The pathology of drug-induced pulmonary toxicity in children is poorly understood and probably under-estimated, in the absence of any prospective studies evaluating in a systematic fashion the side effect of medication on the respiratory apparatus. The pulmonary toxicity of thoracic irradiation has markedly receded with more restricted indications for this sort of treatment. Three clinical patterns are most commonly encountered in drug induced lung disease in children: interstitial lung disease, hypersensitivity lung disease and non-cardiogenic pulmonary oedema. The diagnosis is a diagnosis of exclusion and rests on a group of clinical arguments and also on the progress of the disease. Broncho-alveolar lavage rules out infectious disease. Respiratory function tests show non-specific anomalies. A lung biopsy may be indicated. The mechanism of the pulmonary toxicity are associated with disequilibrium of the oxidant/antioxidant and protease/antiprotease system as well as disturbance of the immune response or alteration of the pulmonary matrix by disease of the collagen system. Increased toxicity may be seen in children because of a very significant cumulative dose. The cytotoxic drugs which are most often implicated in causing this are bleomycin, methotrexate, cyclophosphamide and busulfan. Other drugs which are responsible for toxic lung disease are nitrofurantoin, sulfasalazine, D-penicillamine, betalactams, Diphenyl-hydantoin and carbamazepine. Acute post-radiation lung disease is rare. Post-radiation fibrosis is found six months after irradiation and hinders thoraco-pulmonary growth in the child. It is important to assess lung function in all children before any chemotherapy or thoracic irradiation. Cytotoxic drugs are the most common cause of toxic lung disease. This iatrogenic disease requires a multi-discipline approach to ensure the quality of care for these children.