AUTHOR=Zhang Qiuping , Gong Qiangjin , Sun Xiaokui , Zhu Huizhi 

TITLE=Massive hemoptysis as the sentinel symptom: a case report of pulmonary nocardiosis in an immunocompetent patient

JOURNAL=Frontiers in Medicine

VOLUME=Volume 12 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2025.1677156

DOI=10.3389/fmed.2025.1677156

ISSN=2296-858X

ABSTRACT=Pulmonary nocardiosis is frequently missed or misdiagnosed due to its atypical clinical symptoms and non-specific imaging findings. Moreover, delayed diagnosis and treatment can lead to high mortality rates, underscoring the need to enhance etiological diagnosis. Here, we report a 55-year-old immunocompetent woman who developed pulmonary Nocardia cyriacigeorgica infection with massive hemoptysis as the initial symptom. The patient had no history of chronic respiratory diseases. Metagenomic next-generation sequencing of bronchoalveolar lavage fluid collected via bronchoscopy was performed, which confirmed the diagnosis. After targeted therapy with oral sulfamethoxazole-trimethoprim and linezolid, the patient achieved significant symptomatic and radiological improvement, accompanied by normalization of white blood cell count and neutrophil count. No recurrence was observed during follow-up.