Acute respiratory distress syndrome in a patient with legionella pneumophila. A case report

Patients suffering from pneumonia caused by Legionella pneumophila may experience severe progression, which can lead to acute respiratory distress syndrome and necessitate intensive care unit admission. The diagnosis of Legionnaires' disease relies on clinical presentation and laboratory tests. The urinary antigen test is a primary diagnostic tool for Legionnaires' disease, providing rapid results with high specificity for L. pneumophila serogroup 1. Employing multiple diagnostic methods enhances diagnostic accuracy, particularly in cases where L. pneumophila serogroup 1 is not the causative agent. Among pro-inflammatory cytokines, IL-6 plays a crucial role in the immune response to Legionella pneumophila infection and is associated with the severity of the inflammatory response in Legionnaires' disease. We report on a patient who was admitted to the intensive care unit due to hypoxemic respiratory failure resulting from Legionnaires’ disease. Although the urinary antigen test came back negative, Legionella was strongly suspected based on clinical, paraclinical, and epidemiological evidence, leading to the initiation of targeted antibiotic treatment. The diagnosis was ultimately confirmed through serology. The severity of the inflammatory response was evaluated by measuring serum biomarkers, among them IL-6 levels. This case report outlines the clinical and laboratory parameters that guide intensive care practices.