Etiological distribution and clinical features of fever of unknown origin with pulmonary lesions in South China

Introduction Fever of unknown origin (FUO) with pulmonary lesions is a common syndrome in respiratory diseases, which can be caused by infection, cancer, connective tissue disease and other rare diseases of South China. In patients with FUO associated with pulmonary lesions, pathogeny should be identified and followed by an appropriate treatment strategy. Objective This study aimed to investigate the etiological distribution and clinical features of FUO with pulmonary lesions and to analyze the efficiency of different diagnostic methods for certain disease categories. Methods Patients hospitalized at the Guangzhou Institute of Respiratory Health from July 2012 to December 2016 who had fever ≥38.3°C that lasted ≥21 days, in whom the chest X‐ray or computed tomography (CT) revealed definite pulmonary infiltration, and for whom, despite being examined for a week, no definitive diagnosis could be made, were considered for this study. Results A total of 104 patients were identified as having FUO with lung lesions, and 89.4% (93/104) patients were definitively diagnosed. Infectious disease was the most common cause (46.2%, 48/104). Histopathology was instrumental in the diagnosis of the causes of FUO with pulmonary manifestations, 47.3% (44/93) patients were diagnosed through histopathology, 35.4% (17/48) with infectious disease and 55.2% (16/29) with connective tissue diseases as the etiology were definitely diagnosed using histopathology. Conclusion Most FUO with pulmonary lesions are identified during infections and autoimmune diseases. The most important diagnostic measure for FUO with pulmonary lesions is histopathology. Additionally, lung biopsy must be encouraged in multi‐level hospitals in the future.