Acute fibrinous and organizing pneumonia associated with influenza A/H1N1 pneumonia after lung transplantation

Background: Immunocompromised patients, particularly after lung transplantation, are at high risk to develop atypical forms of pulmonary infections including influenza A/H1N1. Acute Fibrinous and Organizing Pneumonia (AFOP) is a special histological pattern in acute respiratory failure with high mortality. Case presentation: We describe a 66-year-old woman with double lung transplantation in August 2009 due to end stage pulmonary fibrosis. After prolonged weaning and subsequent promising course, she developed atypical pneumonia with diffuse pulmonary infiltrates in both lungs in January 2010. Infection with influenza A/H1N1 virus was verified. The patient rapidly suffered from respiratory insufficiency and died eight days after this diagnosis. The post-mortem revealed especially in the lower parts of the lungs the classical histological pattern of pure AFOP. Molecular analyses of lung tissue were positive for influenza A/H1N1. Conclusion: To our knowledge we present the first case of AFOP triggered by viral infection, here proven to be influenza virus A/H1N1. Thus, also in the setting of viral infection the highly deadly differential diagnosis of AFOP must be considered.