Cholecystoduodenal fistula as an intraoperative finding in a patient with calculous cholecystitis: Case report and expanded discussion

Cholecystoduodenal fistula is the most common form of bilioenteric fistula and typically presents as a late complication of cholelithiasis with chronic cholecystitis. Its clinical expression is heterogeneous, and diagnosis is often established intraoperatively. We present the case of a 44-year-old woman with no comorbidities who presented with severe colicky pain in the right upper quadrant of 10 hours’ duration, accompanied by malaise, subjective fever, and dark urine. On admission, physical examination revealed a positive Murphy sign, without relevant laboratory abnormalities. Ultrasound showed a distended gallbladder with thickened wall and gallstones, a liver with grade II steatosis, and nondilated bile ducts. An urgent surgical approach was chosen, and open cholecystectomy with closure of an intraoperatively diagnosed cholecystoduodenal fistula was performed. Postoperative recovery was favorable, with discharge on postoperative day 3 and drain removal on day 5. We provide a comprehensive discussion of pathophysiology, diagnostic approach, differentiation from other entities (Mirizzi syndrome, gallstone ileus, and Bouveret syndrome), and therapeutic strategies (laparoscopy vs open surgery, duodenal repair, antibiotic management, and the role of ERCP). This case underscores the need to maintain a high index of suspicion in calculous cholecystitis with atypical or persistent features and highlights the importance of timely surgical decision-making to prevent major complications. We also analyze perioperative aspects that optimize outcomes and reduce morbidity and mortality.