[Intra-alveolar hemorrhage in immunodeficient patients]

Occurrence of intra-alveolar hemorrhage (whose theoretical causes are briefly reviewed) in an immunocompromised host raises a number of practical problems, mainly related to the interpretation of bronchoalveolar lavage (BAL) studies undertaken to identify one or more etiologies. An open lung biopsy is often needed in addition to the BAL. Three main nosological groups may be proposed: the acquired immunodeficiency syndrome, in which alveolar hemorrhage is more often caused by a Kaposi sarcoma than by a viral infection often combined with opportunistic diseases; aplasias, in which intra-alveolar hemorrhage may be caused not only by the thrombocytopenia but also by infectious or mycotic diseases; connective tissue diseases and vasculites, mainly systemic lupus erythematosus, that may cause vascular lesions of the lungs. Pathogenesis is still unelucidated, but a combination of alveolocapillary basement membrane lesions and diffuse alveolar damage may be involved.