Autopsy Findings in Eight Patients With Fatal H1N1 Influenza

• Published in: American journal of clinical pathology Vol. 134; no. 1; pp. 27 - 35
• Main Authors: Harms, Paul W., Schmidt, Lindsay A., Smith, Lauren B., Newton, Duane W., Pletneva, Maria A., Walters, Laura L., Tomlins, Scott A., Fisher-Hubbard, Amanda, Napolitano, Lena M., Park, Pauline K., Blaivas, Mila, Fantone, Joseph, Myers, Jeffrey L., Jentzen, Jeffrey M.
• Format: Journal Article
• Language: English
• Published: Chicago, IL American Society of Clinical Pathologists 01.07.2010
• Subjects: Adult; Biological and medical sciences; Bronchopneumonia - pathology; Bronchopneumonia - virology; DNA, Viral - analysis; Fatal Outcome; Hematologic and hematopoietic diseases; Human viral diseases; Humans; Infectious diseases; Influenza A Virus, H1N1 Subtype - genetics; Influenza A Virus, H1N1 Subtype - isolation & purification; Influenza, Human - pathology; Influenza, Human - virology; Investigative techniques, diagnostic techniques (general aspects); Lung - pathology; Lung - virology; Lymphohistiocytosis, Hemophagocytic - pathology; Lymphohistiocytosis, Hemophagocytic - virology; Male; Medical sciences; Middle Aged; Other diseases. Hematologic involvement in other diseases; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Pulmonary Alveoli - pathology; Pulmonary Alveoli - virology; Pulmonary Embolism - pathology; Pulmonary Embolism - virology; Retrospective Studies; Viral diseases; Viral diseases of the respiratory system and ent viral diseases; Young Adult; Diffuse; Human; Respiratory disease; H1N1 influenza; Hemopathy; Hemophagocytosis; Histiocytosis; H1N1; Infection; Diffuse alveolar damage; Hemophagocytic syndrome; Anatomic pathology; Autopsy; Viral disease; Influenza; Lesion
• ISSN: 0002-9173; 1943-7722; 1943-7722
• DOI: 10.1309/AJCP35KOZSAVNQZW

A novel H1N1 influenza A virus emerged in April 2009, and rapidly reached pandemic proportions. We report a retrospective observational case study of pathologic findings in 8 patients with fatal novel H1N1 infection at the University of Michigan Health Systems (Ann Arbor) compared with 8 age-, sex-, body mass index–, and treatment-matched control subjects. Diffuse alveolar damage (DAD) in acute and organizing phases affected all patients with influenza and was accompanied by acute bronchopneumonia in 6 patients. Organizing DAD with established fibrosis was present in 1 patient with preexisting granulomatous lung disease. Only 50% of control subjects had DAD. Peripheral pulmonary vascular thrombosis occurred in 5 of 8 patients with influenza and 3 of 8 control subjects. Cytophagocytosis was seen in all influenza-related cases. The autopsy findings in our patients with novel H1N1 influenza resemble other influenza virus infections with the exception of prominent thrombosis and hemophagocytosis. The possibility of hemophagocytic syndrome should be investigated in severely ill patients with H1N1 infection.