Bilothorax or cholothorax is the accumulation of bile in the pleural cavity. It is the result of direct flow of bile from the biliary tree to the pleural space through a bilopleural fistula of traumatic, infectious or iatrogenic etiology . In a review by Austin, et al., 59 cases of bilothorax were reported from 1960 to 2017 , 13 of which were related to percutaneous biliary drainage (PTBD). Karnik and Shair reported 14 cases from 2000 to 2019 , 4 of which were PTBD related. Bilothorax occurs almost exclusively on the right due to the anatomical location of the liver and biliary tree. It is a rare entity, which needs, nevertheless, immediate treatment and management due to the toxicity and inflammatory effects of bile in the pleural cavity that may result in pleural empyema.
Anatomically, each hemithorax is internally invested by parietal pleura. As the pleura changes direction caudally reflecting to cover the right hemidiaphragm, this reflection forms a continuous line, the right costophrenic sulcus-pleural reflection. On the skin, from front to back, this pleural reflection corresponds to an imaginary line that connects the following spots: 6th rib-anterior midline, 8th rib-right mid-clavicular line, 10th rib-right mid-axillary line, 12th rib-scapular line. When accessing the right biliary system, classical teaching states that the fluoroscopically guided puncture, should be performed on the mid-axillary line below the 10th rib, with the tip of the needle angled 10 degrees cephalad and 10 degrees forward angulation. Staying below the 10th rib and just anterior to the mid-axillary line minimizes the chances of crossing the pleura . While pleural complications are relatively rare (0,5% of PTBD cases performed) , it is not uncommon to traverse the pleural space  during PTBD. The exact rate, however, is unknown. In a series of 230 PTBDs, utilizing a right-sided intercostal approach only one case of bilothorax occurred . In another series of 419 PTBD procedures, two cases of bilothorax were reported .
We believe that in our case, bilothorax occurred for the following reasons: first, and most important, the initial puncture was certainly high, and well through the pleural space as proven, although fluoroscopically it seemed acceptable. Second, the patient was sedated, thereby, full excursion of the lungs and hemidiaphragms was not done to fully appreciate the caudal extent of the right costophrenic sulcus. Third, there was possible malfunction of the drainage catheter associated with the retraction. And, finally, the negative intrathoracic pressure within the pleural space  created a de-facto suction effect, thereby directing bile flow toward the pleural space instead of the duodenum.
Drainage catheters are usually secured on the skin with sutures and/or an adhesive locking device to prevent from external causes of dislodgment. It is important to allow for some slack to be present otherwise the catheter may coil in the intraperitoneal space (or in the pleural space). This is more likely to occur when the procedure is done under sedation, thus the liver is high within the thoracic cavity, which did occur in our patient . Coiling of the catheter in our case was further exacerbated by the increased downward pressure on the liver, exerted by the massive bilothorax. That created an angled rigid catheter course resulting in very tedious guide wire advancement through the catheter lumen. Loss of access in this case would have been catastrophic.
Bilothorax should be suspected in any patient post-PTBD who develops dyspnea, ipsilateral pleuritic chest pain, or septicemia, especially when the biliary drainage catheter has been dislodged. Pleural drainage must be performed with fluid culture/analysis and prompt initiation of empiric antibiotic treatment. At the same time, bile should be prevented from further entering the pleural cavity. Upsizing the drainage catheter to 12Fr or 14Fr was not considered, as the on-going clinical scenario could easily repeat itself. A new puncture was also not an option as there was no biliary dilatation. After documenting that the stent we placed was widely patent, the tract was successfully sealed with Gelfoam pledges and coils to prevent further leakage of bile. The use of compressed gelatin foam pledget in a pre-loaded delivery device (Hep-PlugTM) along the intrahepatic tissue tract has also been reported .