Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 15-27: Malabsorption + Key Features Download Section PDF Listen +++ ++ Malabsorptive condition following removal of significant portions of the small intestine Causes Crohn disease Mesenteric infarction Radiation enteritis Volvulus Tumor resection Trauma Type and degree of malabsorption depend on length and site of resection and degree of adaptation of remaining bowel + Clinical Findings Download Section PDF Listen +++ ++ Terminal ileal resection Watery diarrhea Malabsorption of bile salts and vitamin B12 Low serum vitamin B12 levels Steatorrhea and malabsorption of fat-soluble vitamins Cholesterol gallstones Calcium oxalate kidney stones Extensive (> 40–50%) small bowel resection: short bowel syndrome, characterized by weight loss and diarrhea due to nutrient, water, and electrolyte malabsorption + Diagnosis Download Section PDF Listen +++ ++ Clinical diagnosis based on presence of diarrhea and malabsorption with prior bowel resection + Treatment Download Section PDF Listen +++ +++ Terminal ileal resection ++ Vitamin B12 injections subcutaneously or intramuscularly monthly If watery diarrhea, bile salt-binding resins with meals (cholestyramine, 2–4 g/day orally, colestipol tablets 1–2 g orally once or twice daily, or colesevelam, 625 mg, 1–3 tablets orally twice daily) Cholestyramine or colestipol doses can be slowly increased (cholestyramine maximum 24 mg/day; colestipol tablets 16 g/day), but the higher doses are associated with increased side effects of nausea, bloating, and constipation Calcium supplements to bind oxalate +++ Extensive small bowel resection ++ If the colon is preserved, 100 cm of proximal jejunum may be sufficient to maintain adequate oral nutrition with a low-fat, high–complex-carbohydrate diet If the colon has been removed, at least 200 cm of proximal jejunum is typically required to maintain oral nutrition Parenteral vitamin supplementation Monitor levels of zinc, selenium, and magnesium Antidiarrheal agents (eg, loperamide, 2–4 mg three times daily orally) Octreotide Proton pump inhibitor to reduce acid hypersecretion Total parenteral nutrition (TPN) required if < 100–200 cm of proximal jejunum intact TPN has an estimated annual mortality rate of 2–5% resulting from TPN-induced liver disease, sepsis, loss of venous access Teduglutide Stimulates small bowel growth and absorption Has resulted in a reduced need for parenteral nutrition Small intestinal transplantation, chiefly for patients in whom severe problems develop from TPN