A case of gallstone-induced small bowel necrosis masquerading as clinical appendicitis.

Cholecysto-duodenal fistula and gallstone ileus are well-recognised complications of gallstone disease. However, small bowel necrosis is a rare complication of gallstone disease. We describe a case of gallstone-induced ileal necrosis presenting with symptoms and signs resembling acute appendicitis. A 79-year-old woman presented to the surgical team with central abdominal pain which subsequently shifted to the right iliac fossa. Clinically, the patient had localised perotinism in the right iliac fossa with high inflammatory markers. Abdominal radiography showed no diagnostic features. Initial clinical impression was that of acute appendicitis. Given that this diagnosis was unlikely in a patient of this age, an abdominal CT scan was performed. The CT scan showed evidence of a large gallstone causing small bowel obstruction in the presence of a cholecysto-duodenal fistula. At surgery, she was found to have an area of necrosis with a pin-point perforation at the site of impaction of the gallstone in the proximal ileum. This occurred secondarily to pressure necrosis from the gallstone impacting at a site where the small bowel diameter narrows in transition from jejunum to ileum. A limited small bowel resection was performed with an uncomplicated postoperative course. This case report draws attention to a rare complication of gallstone disease which presents with a clinical picture similar to acute appendicitis. Preoperative investigation for an elderly patient who presents with an acute abdomen should include an abdominal CT scan to diagnose any rare disease processes which otherwise may not be suspected.