Pleural Tuberculosis: Diagnostic Methods in a General Hospital

Introduction: Pleural tuberculosis (PTB) is the most common extrapulmonary presentation. Diagnosis requires the finding of bacillus or the presence of necrotizing granulomas in a tissue sample. Objectives:To describe the diagnostic methods used in patients with PTB. Establish the utility of adenosine deaminase (ADA) determination in pleural fluid. Material and method: This is an observational, descriptive study. We retrospectively analysed all patients hospitalized between January 2008 and December 2015 with pleural effusion (PE) and suspected PTB. The clinical presentation, characteristics of PE and diagnostic methods was compared. The determination of ADA was performed by the Galanti Giusty method. Continuous variables were compared with the t test, Chi square test was used for the comparison of proportions. Results: A total of 146 patients were analysed, of whom 64 were women. PTB was diagnosed in 41 patients. The presence of pleurisy pain, weight loss and haemoptysis was more frequent. The value of ADA was more than 60 IU/ml in 46.3% of patients. The Sensitivity (S), specificity (E), PPV and NPV at thiscut off (according to the National Standards) were 46.3%, 93.1%, 73% and 81.2%, respectively. In the subgroup analysis of cut off ADA values> 35 IU/ml, S was 83% and E was 83% (PPV 67%, NPV 92%). Discussion: According to the current National Standard, a determination higher than 60 IU/ml is considered positive, which in our group of patients results in low sensitivity, PPV and NPV. There are studies that establish cutoff points between 35 and 40 IU/ml. The determination of ADA establishing a cutoff point at 35 IU/ml is an S and E method, with a high NPV that contributes to the diagnosis of PTB.