The lung as a critical organ in marrow transplantation.

Respiratory failure is the main cause of death in patients undergoing bone marrow transplantation (BMT). In this paper, clinical and research aspects as well as diagnostic, prophylactic and therapeutic strategies concerning the various forms of pulmonary and bronchial complications, which may evolve after BMT, are discussed. Both cytomegalovirus (CMV)-induced interstitial pneumonia (PM) and the idiopathic pneumonia syndrome rarely occur in the cytopenic phase post-BMT. Haematological reconstitution with donor type cells seems to be a prerequisite to the development of these complications, suggesting a key role of immunological reactions. While CMV pneumonia can be effectively treated or prevented by ganciclovir, the idiopathic syndrome is usually fatal. Due to improved prophylaxis and therapy, lethal interstitial PM due to Pneumocystis carinii, herpes simplex, varizella zoster or Toxoplasma gondii as well as lethal PM caused by bacteria or Candida species are comparatively rare events. Aspergillus species, on the other hand, have emerged as frequent causative pathogens in lethal PM during the past years. Prolonged granulocytopenia and prolonged medication with corticosteroids are major risk factors of pulmonary aspergillosis, which is usually fatal; effective prophylaxis may be achieved by sterile air supply during the hospital stay and by inhalation of amphotericin B thereafter. Pulmonary haemorrhage, as diagnosed by bronchoalveolar lavage (BAL), may develop due to the toxicity of the conditioning regimen, or may be secondary to infectious PM of various kind. Congestive heart failure or the application of cytokines might give rise to the development of pulmonary oedema. Patients with hepatic veno-occlusive disease have a high risk of subsequent pulmonary complications, possibly on the basis of toxic lung injury. Venous thromboembolism or air embolism may occur; they are usually venous catheter-associated. Pleural effusions may develop secondary to infection, congestive heart failure, veno-occlusive disease, pulmonary embolism or malignancy. Patients with bronchiolitis obliterans, which leads to progressive respiratory failure, present with an obstructive pattern in lung function tests and hyperinflated lungs on chest radiographs.(ABSTRACT TRUNCATED AT 400 WORDS)