S3621 When an Ulcer Crosses the Line: A Rare Case of Biliary-Duodenal Fistula

Introduction: A choledochoduodenal fistula (CDF) is an abnormal connection between the common bile duct and duodenum. These fistulas are rare, with limited case reports since first being described in 1840. The use of advanced hepatobiliary imaging such as endoscopic retrograde cholangiopancreatography (ERCP) and magnetic resonance cholangiopancreatography (MRCP) has improved their detection. Case Description/Methods: A 74-year-old woman with a history of chronic kidney disease, HFpEF, valvular disease, hypertension, hyperlipidemia, hypothyroidism, and an outpatient-treated leg ulcer presented after syncopal episode preceded by dizziness and weakness. In the emergency department, she was hypotensive, heart rate 102, with WBC 28.5. She received intravenous fluids and Ancef for presumed cellulitis. Electrocardiogram normal sinus rhythm, and chest x-ray showed no acute findings. Admitted for further workup, she later developed severe, non-radiating epigastric pain relieved by pantoprazole. Computed tomography A/P revealed extrahepatic biliary dilation (1.4 cm) and duodenal thickening. Blood cultures grew gram-negative rods, and Cefepime was started. On day 4, she developed new-onset Afib with RVR, hypotension, anemia, and hypoxia. She received 2 units packed red blood cells and plasma. MRCP showed common bile duct (CBD) dilation (10 mm), gallbladder distention, free fluid, duodenal/gastric thickening, and lung consolidations. ERCP identified a bleeding duodenal ulcer with suspected CDF; the ulcer was cauterized, and a biliary stent placed. Nonsteroidal anti-inflammatory disease (NSAID) deemed likely cause. Antibiotics escalated to Zosyn, and treated with pantoprazole and hydrocortisone. Due to persistent hypoxia, she was intubated, transferred to intensive care unit for septic shock. Meropenem was started, with improvement allowing extubation the next day. TPN initiated for poor oral intake. Repeat computed tomography showed improved duodenal thickening, early ileus, CDF, CBD stenosis with patent stent, intrahepatic pneumobilia, and free fluid. WBC rose to 31.5; Meropenem course given with plans for Levaquin on discharge. Despite improvement, she continued to require intensive care unit-level care. Discussion: This case highlights gram-negative bacteremia and septic shock secondary to a bleeding NSAID-induced duodenal ulcer complicated by CDF—a rare outcome of peptic ulcer disease (PUD). Though PUD is common, CDF is rare and may cause sepsis, cholangitis, and biliary obstruction. The patient’s nonspecific symptoms initially masked the GI pathology. Imaging and ERCP were key in diagnosing the CDF and managing bleeding. Clinicians should maintain high suspicion for GI sources in elderly patients with sepsis and NSAID use. ERCP remains the diagnostic and therapeutic gold standard.