Surgery MCQs Q33

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SURGERY • HPB

A 34-year-old woman is found on routine testing to have mildly elevated bilirubin and alkaline phosphatase. She recalls one episode of right hypochondrial pain after a heavy fatty meal (cheese and wine). Ultrasound shows multiple small gallstones in the gallbladder and a slightly dilated common bile duct (CBD), though no obvious obstructing lesion is seen.

What is the most likely diagnosis?

A Cholangitis

B Gallstones in gallbladder

C Carcinoma head of pancreas

D Gallstones in the common bile duct

E Infective hepatitis

The correct statement is Gallstones in the common bile duct.

Decoding the Stem

1

CLUE "Biliary colic history + Cholestatic labs + Dilated CBD"

TRANSLATION Gallstones migrated into the CBD (Choledocholithiasis) causing obstruction.

Explanation

D. Choledocholithiasis: ✅ Correct. The combination of an obstructive LFT pattern (↑ bilirubin, ↑ ALP), dilated CBD, and a history of biliary colic strongly points to stones in the CBD. Ultrasound has limited sensitivity for CBD stones (often blocked by bowel gas), so a dilated duct + abnormal labs = CBD stone until proven otherwise.

A. Cholangitis: ❌ Incorrect. This requires Charcot's Triad (fever, jaundice, RUQ pain). While she has pain and jaundice (biochemical), she is afebrile and lacks signs of systemic infection.

B. Gallstones in gallbladder: ❌ Incorrect. Simple cholelithiasis causes pain (biliary colic) but does not cause CBD dilation or elevated bilirubin/ALP unless a stone has migrated.

C. Carcinoma head of pancreas: ❌ Incorrect. Usually presents in older patients with painless progressive jaundice and weight loss, not intermittent colic-like pain triggered by fatty meals.

E. Infective hepatitis: ❌ Incorrect. Hepatitis shows a hepatocellular pattern (massive ↑ AST/ALT) rather than the cholestatic pattern seen here.

🧠 Clinical Pearls

Feature	Clinical Significance
CBD Diameter	>6-7 mm is generally considered dilated (obstruction marker).
LFT Pattern	↑ ALP + ↑ GGT + ↑ Bilirubin = Cholestatic (Obstructive).
US Sensitivity	High for GB stones (>95%), Low for CBD stones (~50%).

Integrated Clinical Questions

1. What is the investigation of choice if ultrasound is inconclusive but CBD stone is suspected?

Answer: MRCP (Magnetic Resonance Cholangiopancreatography) is the best non-invasive test. ERCP is used if therapeutic intervention (stone removal) is planned.

2. What is the definitive management for this patient?

Answer: ERCP with sphincterotomy and stone extraction, followed by Laparoscopic Cholecystectomy to prevent recurrence.

3. Describe Charcot's Triad and Reynolds' Pentad.

Answer: Triad: Jaundice, Fever, RUQ Pain. Pentad: Triad + Hypotension + Altered Mental Status (indicates severe ascending cholangitis).

4. Why does a fatty meal trigger pain in biliary disease?

Answer: Fat in the duodenum triggers the release of Cholecystokinin (CCK). CCK causes gallbladder contraction and relaxation of the Sphincter of Oddi. If a stone obstructs the neck of the GB or the CBD, contraction increases intraluminal pressure, resulting in pain.

5. What is Courvoisier's Law?

Answer: In a patient with painless jaundice, if the gallbladder is palpable, the cause is unlikely to be gallstones. Instead, it suggests a malignancy (e.g., pancreatic cancer) causing chronic distal obstruction, as gallbladders with stones are often scarred and cannot distend.

⚡ Exam Pearls

• CBD dilation = obstruction until proven otherwise.
• Normal CBD is ≤6 mm (add 1mm for every decade over 60).
• Gallbladder stones + abnormal LFTs ≠ simple cholelithiasis; always look for CBD involvement.
• A fatty meal triggers CCK release, causing gallbladder contraction and biliary colic.

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