Bile Acid Malabsorption Caused by Ileal Resection

Two syndromes of bile acid malabsorption caused by ileal resection—bile acid diarrhea (cholerheic diarrhea) and fatty acid diarrhea (steatorrheic diarrhea)—have been identified, characterized, and symptomatic therapy has been developed. In patients with small resections, bile acid malabsorption is mild, and compensatory increase in hepatic synthesis of bile acids is sufficient to restore their secretion. The increased passage of bile acids into the colon causes diarrhea. In patients with large resections, bile acid malabsorption is severe, and increase in bile acid synthesis is insufficient to restore their secretion. This results in impaired micellar dispersion of lipolytic products and malabsorption of fat. Diarrhea responds to removal of long-chain triglycerides from the diet, suggesting that unabsorbed fatty acids or their bacterial products cause the diarrhea in these patients.