Severe Leptospirosis (Weil's Disease) Presenting With Fulminant Alveolar Hemorrhage and Multiorgan Failure: A Case Report.

We report the case of a 50-year-old man admitted to the emergency department with fever, asthenia, and diarrhea, who developed multiorgan failure and acute respiratory distress syndrome (ARDS) due to a massive, abrupt-onset alveolar hemorrhage secondary to leptospirosis infection. Leptospirosis is a zoonosis mainly transmitted by rats, with an increasing incidence in Belgium and the rest of Western Europe. The wide spectrum of symptoms and variability in disease severity make this diagnosis particularly challenging. In this case, initial serological testing, including the microscopic agglutination test (MAT), was negative, leading to a diagnostic delay despite a severe clinical presentation, and the diagnosis was only confirmed after repeated MAT testing. This clinical case describes a severe presentation and highlights the importance of thorough history-taking, including information provided by the patient's relatives, together with repeated etiological testing when clinical suspicion persists. Following intensive care management, the patient showed progressive clinical improvement and was ultimately discharged from the intensive care unit and from the hospital.