Microbiological confirmation of tuberculous pleurisy with medical thoracoscopy: targeted pleural washing and pleural biopsy

Background Due to the pauci-bacillary nature of tuberculous (TB) pleurisy, clinical diagnosis is common, but microbiological confirmation is necessary to determine drug resistance. This study aimed to investigate the diagnostic yield of medical thoracoscopy (MT) for microbiological confirmation of TB pleurisy. Methods Medical records of patients diagnosed as TB pleurisy with microbiological or histologic evidence who underwent MT between May 2015 and July 2023 at Incheon St. Mary's Hospital were retrospectively reviewed. Sensitivities of microbiological results [acid-fast bacilli (AFB) culture or TB-polymerase chain reaction (PCR)] of pre-MT pleural fluid and those of targeted pleural washing fluid and pleural tissues obtained during MT were compared. Difference in sensitivity was verified with McNemar's test. Results A total of 72 patients were enrolled. With pre-MT pleural fluid, sensitivities of AFB culture and TB PCR were 5.6% (4/72) and 1.4% (1/72), respectively. With targeted pleural washing fluid, sensitivities of AFB culture and TB-PCR were 23.6% (17/72) and 12.5% (9/72), respectively. With pleural tissues, sensitivities of AFB culture and TB-PCR were 18.1% (13/72) and 40.3% (29/72), respectively. MT showed an additional 27.8% [95% confidence interval (95% CI): 14.2-40.1%, P Conclusions With MT, 44.4% of additional sensitivity gain in microbiological confirmation of TB pleurisy was identified. This underscores the role of MT in the diagnosis of TB pleurisy.