Acute respiratory distress syndrome in patients with Legionella pneumonia

Objective. The relationship between specific causative organisms anddevelopment of ARDS in pneumonia patients has not been explored.Several case reports have described the development of ARDS in patientswith Legionella pneumonia. The aim is of this study was to determinefrequency and outcomes of ARDS in patients with LegionellaPneumonia. Methods. A retrospective cohort study of patients withLegionella pneumonia hospitalized at two Mayo Clinic Rochester hospitalswas conducted. To identify the patients with Legionella pneumoniawe searched the Mayo Clinic Life Sciences System (MCLSS)database from 01/01/2003 to 12/31/2007. Electronic medical recordsof patients with active Legionella pneumonia based on positive culturesand/or urinary antigen were reviewed. ARDS was diagnosed onthe basis of the criteria of the North American/European consensusconference definition. Results. We identified 15 patients with microbiologicallyproven Legionella pneumonia of whom 11 were admittedto the intensive care unit (ICU), 6 required mechanical ventilation and5 met the criteria for ARDS. Age (median 42 vs. 50 years, p=0.32)and gender (4/10 vs. 1/5 female, p=0.60) were similar in patients withand without ARDS. Septic shock was present in 4 of the 5 patientswith ARDS and only 1 without. Patients with ARDS had longer ICUlength of stay (median 9 vs. 1 days, P=0.03). Only one patient (fromthe ARDS group) died in the hospital. Conclusion. In this retrospectivestudy ARDS occurred in one third of patients with microbiologicallyproven Legionella pneumonia and was associated with prolongedlength of ICU stay.