Etiology of exudative pleural effusion among adults: differentiating between tuberculous and other causes, a multicenter prospective cohort study

Background Exudative pleural effusions have a broad etiology and usually necessitate further investigative work up including invasive procedures. Aims and Objectives The aim of this study is to evaluate and compare the demographic, clinical and biochemical characteristics of tuberculous, malignant and chronic inflammatory pleural effusions. This is a two-year prospective cohort study of patients referred for medical thoracoscopy with an exudative pleural effusion. Results A total of 159 patients were enrolled in the study with a mean age of 42.49 ± 13.8 years with the majority being males 121 (76.1%). As expected, patients with tuberculous effusions were significantly younger than with non-tuberculous effusions (37.7 ± 10.9 vs 49.1 ± 14.9, p <0.001). Serum analysis showed significantly lower white blood cell count (7.5 × 109/L ± 2.7 vs 9.0 × 109/L ± 3.3, p = 0.004), higher total protein (76.2 g/dl ± 10.1 vs 70.2 g/dl ± 8.9 vs, p < 0.001), and higher median CRP (median 77.5, IQR 51, 116 vs median 40.5, IQR 8, 127, p<0.001) among tuberculous compared to non-tuberculosis effusions. Conclusion Our study validates previous findings showing similar results in patients with tuberculous pleural effusions. A predictive model incorporating different demographic and clinical/laboratory characteristics may be useful in early etiological characterization of exudative pleural effusion.