Bile acid malabsorption occurs in patients with terminal ileum resection. Beyond fat malabsorption, which specific complication arises from loss of the enterohepatic circulation of bile salts?

• A Hyperchloremic metabolic acidosis from bicarbonate secreted with bile salts being lost in stool
• B Cholelithiasis (cholesterol gallstones) due to reduced bile salt pool depleting micellar cholesterol solubilization capacity
• C Vitamin K deficiency coagulopathy from fat-soluble vitamin malabsorption and reduced bile salt synthesis
• D Enteric hyperoxaluria — unabsorbed fatty acids bind luminal calcium, leaving oxalate free for colonic absorption causing oxalate kidney stones ✓

Explanation

Ileal resection causes two important downstream effects: cholesterol gallstones (option B is partly correct) and enteric hyperoxaluria. Normally, dietary oxalate is bound by calcium in the gut lumen forming insoluble calcium oxalate (not absorbed). With fat malabsorption, unabsorbed fatty acids bind luminal calcium avidly, leaving oxalate unbound and free for excessive colonic absorption — causing hyperoxaluria and calcium oxalate kidney stones. Option B is also a valid consequence but option D is the specifically 'unique' complication of fat malabsorption + bile salt loss. Option A is incorrect; option C is a consequence of steatorrhea in general.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

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