Gallstone Ileus and Pneumobilia

Question

A 55-year-old woman presents with colicky abdominal pain, distension and bilious vomiting. She has had known gallstones for 10 years. She is dehydrated with a distended abdomen and hyperactive bowel sounds. Heart rate is 120 beats/min, hemoglobin 100 g/L and white cells 18.6 × 10⁹/L. Computed tomography shows dilated small bowel loops with a transition point and air within the biliary tree. Which diagnosis is most likely?

Accepted Answer

C. Gallstone ileus — The pairing of mechanical small bowel obstruction with pneumobilia in a patient with long standing gallstones is the hallmark of gallstone ileus. Despite its name the condition is a true mechanical obstruction, not an ileus, and it occurs when a large stone erodes through the inflamed gallbladder wall into adjacent bowel, creating a cholecystoenteric fistula, usually cholecystoduodenal. The stone then travels distally and impacts where the small bowel is narrowest, typically the terminal ileum, producing colicky pain, distension, bilious vomiting and hyperactive bowel sounds. Air in the biliary tree is the crucial clue, since the fistula allows intestinal gas to pass retrogradely into the ducts. The classic Rigler triad on imaging is small bowel obstruction, pneumobilia and an ectopic gallstone, although all three are seen in a minority of cases. Leukocytosis reflects the inflammatory process and possible bowel compromise. Cholangitis would present with fever, jaundice and cholestatic biochemistry rather than obstruction. Acute cholecystitis causes localised right upper quadrant pain and a positive Murphy sign without small bowel obstruction. Gallstone pancreatitis causes epigastric pain radiating to the back with markedly raised pancreatic enzymes. Treatment is resuscitation followed by enterolithotomy, with management of the fistula and gallbladder decided case by case.

Gallstone Ileus and Pneumobilia

Explanation

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