Suspected common bile duct stone — MRCEM SBA MCQ

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EasyProcedures, imaging and diagnosticsSuspected common bile duct stoneMRCEM SBA

A 47-year-old woman presents to the emergency department after an episode of right upper quadrant pain that has now settled. She is mildly jaundiced but afebrile and haemodynamically stable. Her bilirubin is 46 micromol/L and alkaline phosphatase is 238 U/L. Transabdominal ultrasound shows gallbladder stones and a 9 mm common bile duct, but no duct stone is seen. There is no sonographic evidence of acute cholecystitis. Which investigation is most appropriate next to assess for a common bile duct stone?

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Correct answer: C — Magnetic resonance cholangiopancreatography

The dilated common bile duct and abnormal liver function tests sustain suspicion of a duct stone despite the negative ultrasound finding. NICE recommends considering magnetic resonance cholangiopancreatography (MRCP) when ultrasound has not detected a common bile duct stone but the duct is dilated and/or liver function tests are abnormal. She is stable, with no features in the stem requiring immediate biliary drainage. She needs ongoing clinical assessment while duct imaging and the subsequent treatment plan are arranged. ([nice.org.uk](https://www.nice.org.uk/guidance/cg188/resources/gallstone-disease-diagnosis-and-initial-management-35109819418309)) A repeat transabdominal ultrasound is less useful after an adequate scan has already established duct dilatation without identifying a stone; repeating it could be reasonable if the first study were technically inadequate. Contrast-enhanced CT may help if another abdominal diagnosis is suspected, but it is not the recommended next test for this specific unresolved question. Endoscopic ultrasound is a plausible way to investigate duct stones, but NICE places it after MRCP if MRCP does not establish a diagnosis. ERCP can clear a duct stone and may be needed subsequently, but proceeding directly to this invasive intervention is not the best diagnostic step in this stable patient without a demonstrated duct stone. ([nice.org.uk](https://www.nice.org.uk/guidance/cg188/resources/gallstone-disease-diagnosis-and-initial-management-35109819418309))

Reference: NICE CG188, Gallstone disease: diagnosis and management — recommendations (29 October 2014; last reviewed 31 August 2018) — https://www.nice.org.uk/guidance/cg188/resources/gallstone-disease-diagnosis-and-initial-management-35109819418309 NICE CG188, Gallstone disease: diagnosis and management — key priorities for implementation (29 October 2014) — https://www.nice.org.uk/guidance/cg188/chapter/2-research-recommendations