Retrospective analysis of necropsy findings in patients of H1N1 and their correlation to clinical features.

India reported its first case of H1N1 in July 2009 in Pune and since then, the number of reported cases and deaths exploded in India. Since very little data is available about histopathological findings in patients of H1N1 fatal cases in India, a retrospective chart analysis of necropsy findings of 15 cases of 2009 H1N1 fatal cases was performed. Common clinical features were fever, cough, and breathlessness followed by sore throat and rhinorrhea. Common lung findings were mononuclear cell infiltration, thick alveolar septae, intraalveolar hemorrhage. The other findings were congested pulmonary blood vessels, pulmonary edema, cytomegaly, fibrin accumulation and formation of eosinophilic membrane. These findings are suggestive of diffuse alveolar damage (DAD) and DAD with hemorrhage. All patients who underwent necropsy had radiographic findings suggestive of unilobar or multilobar pneumonia. This clinical finding can be correlated pathologically in these patients as all of them had either polymorphonuclear or mononuclear infiltrate. Furthermore, necrotizing pneumonitis pattern seen on these patients is the likely cause of mortality in these patients. Although clinical ARDS pattern was noted in all these patients, it was well correlated in lung pathology in all these cases.