CRA1 BROWN PLEURAL EFFUSION IN PATIENTS WITH ADENOCARCINOMA: A CASE SERIES ANALYSIS

Lee XY1, Huan NC2, Larry EN3, Hema Y2, K. Kannan2
1Department of Medicine, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
2Department of Respiratory Medicine, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia
3Department of Medicine, University Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia

Introduction:

Bilothorax, characterized by the presence of bile in the pleural cavity, is usually suspected in any patient with olive green or brown pleural effusion. A raised pleural fluid-to-serum bilirubin ratio of >1.0 is the most specific diagnostic test. It is a rare phenomenon often linked to biliary diseases or procedures. Its manifestation in adenocarcinoma patients without apparent biliary involvement presents a diagnostic conundrum. 

Objectives:

To demonstrate the atypical presentation of bilothorax in adenocarcinoma, offering insights into its diagnosis and clinical implications of raised pleural fluid bilirubin to guide clinicians and researchers in navigating these clinical scenarios.

Methodology:

4 case summaries were reviewed and information extracted to demonstrate the occurrence of bilothorax. 

Results:

4 patients of biochemically proven bilothorax identified.  All 4 cases received a final diagnosis of adenocarcinoma (3 lung origins and 1 gastric origin), with no apparent fistula between pleural cavity and hepatobiliary system. Postulates for the development of brown effusion include haem oxygenase-1 (HO-1) overexpression in malignant cells situated in the pleura, intrapleural haemolysis following malignancy-related haemorrhage, and passive movement of bile through the diaphragmatic pores and drainage of biliary fluid into pleural lymphatics. All patients were commenced on prophylactic antibiotics although none developed frank pleural infection eventually. 

Conclusion:

Further research is warranted to explore these postulates and to study clinical and prognostic implications of raised pleural fluid bilirubin levels in patients with malignant effusions.