Etiology of pleural effusions in a general hospital

AIM: To describe the characteristics of patients with pleural effusion (PE) treated in a General hospital in the last four years. METHODE: We included all patients who underwent diagnostic thoracentesis from 1 January 2010 until 31 December 2013 at our center. Chart review was performed to obtain baseline characteristics, clinical diagnosis and mortality. RESULTS: 728 patients were included. Causes of PE: 213 (29%) infectious non-TB, 189 (26%) congestive heart failure (CHF), 157 (21%) malignant, TB 23 (3%), other diagnosis 15%; in 30 patients (4%) PE was considered idiopathic. We obtained a positive bacteriological culture only in 80 (37%) of the infectious PE. Among the malignant PE, pleural fluid cytology was positive in 91 patients (58%). In patients with CHF, 46.5% had protein in pleural fluid (PF) > 2.5 g/L, and in the 39% of the 103 patients who had LDH measured it was higher than 200U/L. In patients with infectious PE, 23% had PF protein CONCLUSIONS: 1. Pleural effusion is associated with high mortality; 2. In infectious non-TB pleural effusions the germ is isolated only in 1/3 of the cases; 3. In malignant PE, cytology diagnosis contributes in less than 60% of cases requiring the implementation of other diagnostic procedures; 4. Determination of isolated proteins and LDH in pleural fluid is not useful to discriminate between transudates and exudates PE, given the high false positive in patients with CHF.