Investigating causes of undiagnosed exudative pleural effusion by medical Pleuroscopy and close biopsy

Introduction: Pleural effusion may develop during various acute or chronic medical conditions. Despite different diagnostic workups, some cases of pleural effusion may remain undiagnosed. Pleuroscopy and closed biopsy are common diagnostic approaches used for the diagnosis of undiagnosed cases. The present research aimed to evaluate the diagnostic yield of medical pleuroscopy and closed biopsy in Iran. Materials and methods: The present cross-sectional study was performed within 2016-2018, in the North-East of Iran. Patients who had undiagnosed lymphocytic predominance exudative pleural effusion were included in the present research. Every patient underwent medical pleuroscopy or closed pleural biopsy by an Abrams needle. The collected data were analyzed in SPSS software (version 12).Ap-valuelessthan0.05 was considered statistically significant. Results:A total of 108 patients with the mean age of 58.73±18.13 years enrolled in the present study. Around 50 patients underwent needle biopsy,while the other 58 patients went through medical pleuroscopy. Chronic pleuritis, malignant pleural effusion, negative results, and tuberculosis were the common results. When pleuritis is regarded as negative results and malignant and tuberculosis pleural effusion as positive results, medical thoracoscopy provides more significant positive results and fewer negative results (P=0.024). No patient developed complications after the procedures. Conclusion: In contrast to other studies, both of these techniques had low diagnostic yield for the diagnosis of undiagnosed pleural effusion. Therefore, performing other diagnostic workups (e.g., imaging techniques) may decrease the rate of undiagnosed pleural effusion.