At cholecystectomy, numerous small, jet-black, brittle stones are recovered from a 25-year-old man. These stones are composed chiefly of calcium bilirubinate. Which underlying disorder most strongly predisposes to this type of stone?

• A Obesity with rapid weight loss after bariatric surgery
• B Hereditary spherocytosis ✓
• C Terminal ileal Crohn disease
• D Multiparous pregnancy

Explanation

Black pigment stones form when chronically elevated unconjugated bilirubin, as in hereditary spherocytosis and other hemolytic states, precipitates as calcium bilirubinate along with calcium carbonate and phosphate. Obesity, rapid weight loss, estrogen exposure, and multiparity promote cholesterol stones instead by increasing biliary cholesterol secretion. Terminal ileal Crohn disease predisposes to brown pigment stones, which are softer, earthy, and driven by bacterial deconjugation in infected stagnant bile.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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