Evaluation of clinical risk factors for developing pleural empyema secondary to liver abscess

Background: The aim of this study was to investigate the clinical manifestation and predictive risk factors of pleural empyema developing during treatment of the pyogenic liver abscess. Methods: Medical records of patients with the liver abscess in our institution were reviewed retrospectively. Enrolled patients were classified into four groups; Group 1: patients without pleural effusion, Group 2: patients with pleural effusion and who were treated noninvasively, Group 3: patient with pleural effusion and who were treated with thoracentesis, and Group 4: patients with pleural effusion that developed into empyema. Patient characteristics, clinical manifestation, and possible risk factors in development of empyema were analyzed. Results: A total of 234 patients was enrolled in this study. The incidence rate of empyema was 4.27% (10 patients). The mean interval for developing pleural effusion was 5.6 ± 6.35 days. In multivariate analysis, risk factors for developing pleural effusion included the location of the liver abscess near the right diaphragm (segment 7 and 8, OR = 2.30, p = 0.048), and larger diameter of the liver abscess (OR = 1.02, p = 0.042). Among patients who developed pleural effusions, presences of mixed microorganisms from culture of liver aspirates (OR = 10.62, p = 0.044), bilateral pleural effusion (OR = 46.72, p = 0.012) and combined biliary tract inflammation (OR = 21.05, p = 0.040) were significantly associated with the need for invasive intervention including surgery on effusion. Conclusion: The location of the liver abscess as well as pleural effusion, elevated inflammatory markers, and combined biliary tract inflammation may be important markers of developing pleural complication in patients with pyogenic liver abscess.