Diagnostic accuracy of semirigid thoracoscopy in exudative pleural effusions and relationship of thoracoscopic findings with probability of malignant diagnosis.

Semirigid thoracoscopy is increasingly becoming the procedure of choice for evaluation of undiagnosed exudative pleural effusions. Few studies have reported relationship of thoracoscopic appearances of pleural abnormalities and etiological diagnoses. We aimed our study to assess the diagnostic utility and safety of semirigid thoracoscopy for evaluation of patients with undiagnosed exudative pleural effusion. Further, we also pursued to find any relation of various thoracoscopic findings with the final diagnosis. We prospectively enrolled hospitalized patients with undiagnosed exudative pleural effusion who underwent semirigid thoracoscopy. Demographic, clinical and laboratory data along with data on thoracoscopic appearance of various pleural abnormalities and histopathological diagnosis of pleural biopsy specimens were collected and analysed. Semirigid thoracoscopy was diagnostic in 46 (N=55) patients (83.64%). Malignancy was diagnosed in 31 patients (56.36%), of which adenocarcinoma was the most common histopathological diagnosis (45.16%).  Sensitivity, specificity, PPV, NPV LR+ and LR- of thoracoscopy were 93.87%, 100%, 100%, 66.67%, 40.30 and 0.06, respectively. Pleural nodules, masses and hemorrhagic pleural fluid significantly increased the diagnosis yield of malignancy [OR= 37.16 (95%CI = 3.61-382.65),  =0.002]. The procedure related complications were mild and transient. Post- procedural pain (20%) was most commonly reported followed by dry cough (18.18%), sub-cutaneous emphysema (7.27%) and anaesthesia related complication (1.82%). Semirigid thoracoscopy is simple, safe and effective procedure in diagnosing exudative pleural effusion of unknown etiology with high diagnostic accuracy and minor procedure related complications. The likelihood of diagnosing malignancy is high if combination of pleural nodules, masses and hemorrhagic pleural fluid is present.