RESUMO
OBJECTIVE: To find histopathological changes on major organs of Influenza A H1N1-infected patients and its relationship to clinical symptoms. METHODS: The autopsies were performed following conventional protocols and strict safety procedures. Tissue samples from all major organs of three cases were collected and fixed in 4% formalin. The histopathological changes on these samples were observed under a light microscope. RESULTS: The lungs of some damaged areas of three cases showed diffuse alveolar damage (DAD) with hyaline membranes formation and intra-alveolar edema and/or fibrin. Most areas of the lungs in the three cases showed necrotizing bronchiolitis, hemorrhage, secondary infection, thrombosis and focal alveolar necrosis. The lungs exhibited proliferation of pneumocytes and fibrosis of the interstitium in one case. In one case, the brain showed focal hemorrhage and focal liquefactive necrosis. In one case, the heart showed edema. CONCLUSION: The respiratory tract is the major target of influenza A H1N1 virus. The changes of DAD with secondary infection in the lung resulted in hypoxia, leading to multiple organ failure and death.
