When the Pleural Fluid Appears in an Unexpected Color: A Bilothorax Case

Abstract Background: Bilothorax, or cholethorax, is a rare cause of exudative pleural effusion characterized by the presence of bile in the pleural space. Recognizing this condition is essential to prevent severe complications such as empyema and acute respiratory distress syndrome. Case: This report presents a 70-year-old male patient who developed right-sided bilothorax following multiple biliary tract interventions. The patient presented with symptoms of jaundice, fever, and abdominal pain. Clinical and radiological evaluations revealed right-sided pleural effusion, and thoracentesis yielded dark yellow-green fluid. The diagnosis of bilothorax was confirmed by a pleural fluid/serum total bilirubin ratio >1.0. Early intervention was performed using a cystofix to drain the pleural fluid. However, despite all interventions, the sepsis condition could not be controlled, and the patient unfortunately passed away. Discussion: Bilothorax is generally associated with hepatobiliary procedures and is mostly observed on the right side due to anatomical proximity. Diagnosis requires a high index of suspicion, especially in patients with relevant clinical histories and characteristic pleural fluid appearance. Rapid thoracentesis and pleural fluid analysis are crucial for diagnosis. Treatment typically involves pleural drainage and early administration of broad-spectrum antibiotics. Conclusion: Bilothorax is a life-threatening condition requiring urgent diagnosis and intervention. This case highlights the importance of recognizing this rare condition and the necessity for early aggressive management in patients with a history of hepatobiliary procedures.