Misdiagnosis of pneumorrhagia leptospirosis as common CAP: A case report and literature review.

Background: The incidence of critical leptospirosis manifested as massive pulmonary hemorrhage has been significantly reduced, which has been rarely reported in recent years, while the mortality rate is extremely high once it occurs. Case presentation: A 54-year-old man with no HIV infection was admitted to the local county hospital due to high-grade continuous fever lasting four days (38.5-40.5C), upper limb and shoulder-back muscle pain, and general fatigue. The chest CT (Aug 26, 2021) showed "multiple patchy, cloudy, and fuzzy shadows in both lungs, mainly under the pleura of the upper and lower lobes of both lungs; some lymph nodes in the mediastinum are enlarged". Despite being diagnosed with "common community-acquired pneumonia" and starting injectable levofloxacin, the symptoms worsened, and massive hemoptysis occurred. However, after being transferred to our hospital, the patient was diagnosed with the "pulmonary hemorrhage type of leptospirosis" through comprehensive dynamic analysis. The patient recovered very well after undergoing "penicillin 3MIU q6h" alone for two weeks to fight the infection. Conclusions: Leptospirosis has a high mortality rate when it becomes critical or severe. Diagnosis typically relies on factors such as epidemiology, clinical symptoms, and pathogenetic testing. Metagenomic next-generation sequencing (mNGS) is more effective in sensitivity and speed than traditional detection methods, making it an excellent option for diagnosing challenging and severe infections in emergencies. Additionally, when experiencing sudden coughing up of blood, it's important to consider the possibility of pulmonary hemorrhage as a type of leptospirosis.