title: Pandemic influenza A/H1N1: comparative analysis of microscopic lung histopathological findings.
abstract: OBJECTIVE
  To analyze the histopathological lung findings of four fatal cases of the 2009 H1N1 influenza pandemic and their correlation with clinical and epidemiological characteristics.
  
  
  METHODS
  Descriptive data from medical records of four patients who died in the Intensive Care Unit of a university hospital in 2009. Nasopharyngeal aspirate specimens were collected from the patients and were analyzed by real-time polymerase chain reaction. Lung biopsy was performed post mortem; a score of intensity for pathological changes was applied.
  
  
  RESULTS
  Three patients had positive real-time polymerase chain reaction (although all of them had a clinical diagnose of influenza H1N1). The main histopathological changes were: exudative diffuse alveolar damage with atelectasis; varying degrees of alveolar hemorrhage and edema, necrosis and sloughing of the respiratory epithelium in several bronchioli; and thrombus formation. One of the patients (the pregnant one) presented histopathological findings of cytomegalic inclusion.
  
  
  CONCLUSIONS
  The pulmonary histopathological findings in patients with fatal 2009 H1N1 influenza pandemic disclosed intense alveolar damage and hemorrhage and severe bronchiolitis. A co-infection with cytomegalovirus was described in the pregnant patient.
authors: Hospital Universitário do Oeste do Paraná, Cascavel, PR, Brasil.
authors: Roberta
authors: R
authors: Marchiori
authors: Carla Sakuma de Oliveira
authors: CS
authors: Bredt
authors: Marcos Menezes Freitas de
authors: MM
authors: Campos
authors: Fábio
authors: F
authors: Negretti
authors: Péricles Almeida Delfino
authors: PA
authors: Duarte
mesh_terms: D000328:Adult; D000368:Aged; D001938:Brazil / Q000453:epidemiology; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000453:epidemiology / Q000473:pathology* / Q000821:virology; D008168:Lung / Q000473:pathology* / Q000821:virology; D008875:Middle Aged; D058873:Pandemics; D011247:Pregnancy; D012189:Retrospective Studies; D055815:Young Adult