title: Differential diagnosis of diffuse alveolar haemorrhage in immunocompromised patients.
abstract: OBJECTIVE
  Diffuse alveolar haemorrhage (DAH) is a life-threatening medical emergency in immunocompromised and immunocompetent patients characterized by haemoptysis, anaemia, acute respiratory failure and diffuse pulmonary infiltrates on radiologic examination. This review describes DAH imaging features, causes and main differential diagnosis.
  
  
  RESULTS
  In immunosuppressed patients, DAH occurs most frequently in haematologic neoplasms, after haematopoietic stem cell transplantation or solid organ transplantation, secondary to drug reaction or infection, and associated with AIDS. However, differential diagnoses of all of these conditions include several conditions with similar findings.
  
  
  CONCLUSIONS
  Imaging patterns of DAH do not differ significantly from those of conditions included in the main differential diagnosis. The differential diagnosis depends on the patient's immunity status. In immunocompromised patients, infection and lung injury of other causes must be considered.
authors.affiliation: aDepartment of Radiology, Federal University of Paraná, Curitiba bDepartment of Radiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Dante Luiz
authors.initials: DL
authors.lastname: Escuissato
authors.forename: Danny
authors.initials: D
authors.lastname: Warszawiak
authors.forename: Edson
authors.initials: E
authors.lastname: Marchiori
mesh_terms: D003937:Diagnosis, Differential; D006470:Hemorrhage / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D016867:Immunocompromised Host; D008171:Lung Diseases / Q000175:diagnosis* / Q000473:pathology; D013902:Radiography, Thoracic / Q000379:methods