A46-02 Discordant Pleural Chemistries Unmask a Pancreaticopleural Fistula

Abstract Introduction Pancreaticopleural fistula (PPF) is an exceptionally rare (1% of pancreatitis-related complications) cause of pleural effusion in which enzyme-rich pancreatic secretions enter the pleural space. Delayed diagnosis is common when effusions are bilateral and chemistries are discordant. We report a young adult with an amylase-rich exudate contralateral to a transudate driven by pancreatic ascites and profound hypoalbuminemia. Case Report A 37-year-old man with polysubstance use, severe malnutrition, and a recent critical-illness admission re-presented weeks later with abdominal pain, distention, and shortness of breath. CT showed large-volume ascites, a 16 cm loculated upper-abdominal collection, and a 9 mm pancreatic-tail pseudocyst with side-branch dilation; small bilateral effusions were present with dependent opacities. Initial respiratory status required low-flow NC with basal atelectasis from abdominal splinting. Pleural fluid profiles were discordant (Table 1): the right thoracentesis demonstrated an amylase-rich exudative pattern consistent with PPF, while the left revealed transudative features in the setting of pancreatic ascites/low oncotic pressure. Ascites had low SAAG. Lung ultrasound showed no complex septations requiring drainage. MRCP did not visualize a pleural tract; given the biochemical profile, PPF was presumed, and octreotide SQ TID was started. Definitive endoscopic therapy followed: EUS-guided cyst-gastrostomy with a 10 x 10 lumen-apposing metal stent decompressed the pseudocyst. ERCP identified a tail-duct leak (∼4 mm); a 7 Fr x 15 cm transpapillary stent was deployed across the defect. The patient’s oxygen requirement fell to baseline (room air) with rapid symptomatic improvement; chest tubes were avoided. Interval endoscopic stent removal was planned with GI. Discussion Despite nondiagnostic MRCP, the combination of ERCP-proven duct disruption, amylase-rich pleural fluid, and clinical response after ductal stenting establishes a functional PF with retroperitoneal transdiaphragmatic tracking. This case highlights three practice points: 1. Obtain pleural chemistries. High amylase mandates pancreatic imaging and GI consultation. Early recognition of PPF in unexplained or recurrent effusions, especially when chemistries are discorodant, steamlines care and improves outcomes. 2. Beware of discordant bilateral effusions. A contralateral transudate from pancreatic ascites/hypoalbuminemia can misdirect if only one side is ampled or if empiric diuresis is pursued. 3. Endoscopic-first management works. EUS drainage plus ERCP stenting, with adjunctive octreotide, can obviate chest tubes and surgery, hasten respiratory recovery, and reduce recurrence. This abstract is funded by: None