[Fulminant influenza pneumonia].

Severe community acquired pneumonia is a common cause of acute respiratory failure requiring ventilator support. Bacteria are by far the most common pathogens, necessitating initial coverage with antibacterial agents. When influenza virus is involved in the aetiology of severe pneumonia, its role in the pathogenesis is most often that of facilitating secondary bacterial pneumonia. The influenza virus itself can, however, cause a severe and rapidly evolving viral pneumonia. We describe two cases of fulminant pneumonia with multiorgan failure, in which extensive microbiologic and serologic diagnostic test did not reveal other causes for the pneumonia than influenza virus. Different clinical lung manifestations of influenza are discussed. Influenza must be considered as an aetiologic possibility in acute respiratory failure.