The pathology of influenza

The authors present a systematic pathological study of cases from the 1918 influenza epidemic, based on eighty-two autopsies, detailing gross and microscopic findings. They describe necrotizing hemorrhagic lesions of the trachea and bronchi and several pulmonary patterns including acute diffuse fulminant hemorrhagic pneumonia, localized necrotizing pneumonias, and organizing bronchiolar/alveolar exudates. The work documents extrarespiratory effects on lymphoid tissues, spleen, bone marrow, blood vessels, the alimentary and urinary tracts, central nervous system structures, and changes observed in pregnancy. A comparative analysis contrasts these lesions with those produced by inhaled poisonous gases and emphasizes peculiar histologic features such as hemorrhagic and hyaline necrosis and patterns of organization. Bacteriological findings and their relation to pleural involvement and pneumonic types conclude the study.