Morphological and Ultra Structural Findings in Influenza A (H1N1)
A Fernandez, K Arispe, D Moran, JC Leon, D Montante, E Reyes-Gutierrez, A Angeles-Angeles, A Gamboa-Dominguez. Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, Tlalpan, Mexico
Background: In March an outbreak of severe respiratory infection began in Mexico that was subsequently attributed to a novel human/swine origin influenza A (H1N1) virus. A second wave of illness started in September 2009.
Design: Objective: to describe the demographic, clinical and morphological findings in surgical and autopsies studied in a referral center in Mexico City. Material and methods: Autopsies and open lung biopsies of suspected cases of influenza A (H1N1) were included in this series. Information of nasopharyngeal swab tested for nucleic acid detection was searched in charts. The demographic, clinical course, co morbidities, morphological and ultra structural characteristics of positive cases is described.
Results: Since March four autopsies were performed out of five deceased positive patients, and an open lung biopsy of an external patient. All cases started one to five days previous to develop acute respiratory distress and to require mechanical ventilator support. Age ranged from 32 to 56 years with a mean of 41. Initial complaints were productive cough, fever, chest pain and dyspnea in all cases. Co morbidities were documented in all death patients (constrictive pericarditis, chronic malnourishment, systemic lupus erythematosus and anorexia), but in the biopsied patient who was the only male and previously in good health. In 2/5 patients oseltamivir was started without clinical improvement. Anemia and peripheral cytopenia were documented in autopsied cases. Hydrothorax, hemorrhagic lung consolidation and diffuse alveolar damage were documented in all patients. Lung, lymph node, bone marrow and liver hemophagocytosis was observed. Alveolar macrophages showed electron dense structures surrounded by membranes close to nuclear envelope and to the cytoplasmic membrane.
Conclusions: Influenza A (H1N1) complicate the clinical course of chronically ill young patients and is associated with diffuse alveolar damage, hemophagocytosis and electron dense structures in alveolar macrophages.
Wednesday, March 24, 2010 1:00 PM
Poster Session VI # 211, Wednesday Afternoon