Intestinal malabsorption of ingested nutrients may produce osmotic diarrhea, steatorrhea, or specific deficiencies (e.g., iron; folate; B12; vitamins A, D, E, and K). Table 42-3 lists common causes of intestinal malabsorption. Protein-losing enteropathy may result from several causes of malabsorption; it is associated with hypoalbuminemia and can be detected by measuring stool α1-antitrypsin or radiolabeled albumin levels. Therapy is directed at the underlying disease.
|Maldigestion: Chronic pancreatitis, cystic fibrosis, pancreatic carcinoma|
|Bile salt deficiency: Cirrhosis, cholestasis, bacterial overgrowth (blind loop syndromes, intestinal diverticula, hypomotility disorders), impaired ileal reabsorption (resection, Crohn’s disease), bile salt binders (cholestyramine, calcium carbonate, neomycin)|
|Inadequate absorptive surface: Massive intestinal resection, gastrocolic fistula, jejunoileal bypass|
|Lymphatic obstruction: Lymphoma, Whipple’s disease, intestinal lymphangiectasia|
|Vascular disease: Constrictive pericarditis, right-sided heart failure, mesenteric arterial or venous insufficiency|
|Mucosal disease: Infection (esp. Giardia, Whipple’s disease, tropical sprue), inflammatory diseases (esp. Crohn’s disease), radiation enteritis, eosinophilic enteritis, ulcerative jejunitis, mastocytosis, tropical sprue, infiltrative disorders (amyloidosis, scleroderma, lymphoma, collagenous sprue, microscopic colitis), biochemical abnormalities (gluten-sensitive enteropathy, disaccharidase deficiency, hypogammaglobulinemia, abetalipoproteinemia, amino acid transport deficiencies), endocrine disorders (diabetes mellitus, hypoparathyroidism, adrenal insufficiency, hyperthyroidism, Zollinger-Ellison syndrome, carcinoid syndrome)|
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