# Diagnostic Yield and Safety of Medical Thoracoscopic Biopsy in Undiagnosed Exudative Pleural Effusion: A Five-Year Retrospective Study From a Tertiary Care Center in South India

## TL;DR

This study shows that medical thoracoscopy is a safe and highly effective diagnostic tool for undiagnosed pleural effusions, especially in detecting malignancies.

## Contribution

The study provides robust data on the diagnostic yield and safety of thoracoscopy in a high-volume Indian tertiary center with evolving disease patterns.

## Key findings

- Medical thoracoscopy achieved a 99.4% diagnostic yield in undiagnosed exudative pleural effusions.
- Malignancy was the most common diagnosis (64.6%), primarily lung adenocarcinoma.
- Complications were mostly minor, with no procedure-related mortality observed.

## Abstract

Background: Medical thoracoscopy is a minimally invasive procedure with high diagnostic yield in undiagnosed exudative pleural effusions. There is limited data on its efficacy and safety from high-volume tertiary centers in India, considering the changing etiological spectrum.

Methods: This is a retrospective observational study including all consecutive patients who underwent medical thoracoscopy for undiagnosed exudative pleural effusion at a tertiary care teaching hospital in South India over a five-year period. Data were obtained from departmental records and analyzed for diagnostic yield, etiology, macroscopic findings, therapeutic interventions, complications, and outcomes.

Results: A total of 305 patients were included (mean age 57 ± 15.5 years; 60.3% male). An etiological diagnosis was achieved in 303 patients, yielding a diagnostic yield of 99.4%. Malignancy was the most common diagnosis (64.6%), predominantly lung adenocarcinoma (77.1% of malignancies), followed by benign causes (35.4%), with tuberculosis accounting for 14.4% overall. Nodules (59.7%) and adhesions (41.3%) were the most frequent macroscopic findings, correlating strongly with malignant and infective etiologies, respectively. Talc pleurodesis and adhesiolysis were performed in 18.7% and 23.0% of cases, respectively. Complications were predominantly minor: post-procedure pain (66.6%), followed by subcutaneous emphysema (7.2%). Major complications were rare (hemorrhage 0.3%, prolonged air leak <2%). No procedure-related mortality occurred.

Conclusion: Pulmonologist-performed medical thoracoscopy demonstrated high diagnostic yield and an excellent safety profile in undiagnosed exudative pleural effusions. The predominance of malignancy reflects changing epidemiological trends and supports early thoracoscopic evaluation in undiagnosed exudative pleural effusion.