Snapshot An 85-year-old woman presents to the emergency department with nausea, vomiting, and abdominal pain. She states her symptoms started 1 week ago. She describes the pain as crampy, intermittent, and localized to the right upper quadrant (RUQ). She has a history of hypertension and cholelithiasis. On physical exam, mucous membranes are dry and abdominal RUQ is tender to palpation. Abdominal radiograph reveals dilated loops of small bowel and gas in the biliary tree. Introduction Clinical definition mechanical obstruction of the bowel by a large gallstone Epidemiology Demographics most commonly seen in elderly women Risk factors elderly chronically inflamed gallbladder gallstones > 2 cm etiology Pathogenesis caused by perforation and cholecystenteric fistula formation connecting the an inflamed gallbladder with the bowel most common sites are the ileocecal valve and the terminal ileum Presentation Symptoms episodic bowel obstruction nausea vomiting constipation abdominal pain abdominal distension may be seen in severely ill patients with altered mental status who may not be able to localize pain Physical exam fever abdominal tenderness abdominal distension signs of dehydration imaging Abdominal computed tomography (CT) gold standard for diagnosis Riger triad pneumobilia air in the biliary tract intestinal obstruction obstructing/ectopic gallstones Abdominal ultrasound may be more sensitive for pneumobilia may help identify location of gallstones but intestinal gas can reflect ultrasound waves, which limits gallstone visualization Abdominal radiograph if CT or ultrasound not available Studies Diagnostic testing studies cholescintigraphy/hepatobiliary iminodiacetic acid (HIDA) scan consider if CT is not diagnostic Treatment Management approach primarily surgical to address intestinal obstruction, cholelithiasis, and biliary-enteric fistula First-line enterolithotomy (enterotomy with stone removal) may require bowel resection where there is perforation, significant ischemia, or a gallstone that cannot be dislodged Second-line cholecystectomy and biliary-enteric fistula closure indication in low-risk patients can undergo biliary procedure same time as enterolithotomy in high-risk patients (i.e., American Society of Anesthesiologists (ASA) class III or IV, patients in shock, or who have significant intra-abdominal inflammation/adhesion) can be performed at a later time after enterolithotomy if recurs or when condition permits Other treatments prophylactic antibiotics indication for peri-operative period i.e., cefoxitin lithotripsy indication if poor surgical candidate Complications Mortality higher risk compared with other causes of mechanical bowel obstruction majority of patients with gallstone ileus are older and with serious concomitant medical conditions Recurrent gallstone ileus especially with enterolithotomy alone