Mechanisms of Malabsorption
Mechanisms of Malabsorption
Location | Disease | Mechanism |
|---|---|---|
Luminal | Exocrine pancreatic insufficiency | Lack of pancreatic enzymes (maldigestion) |
Luminal | Small-intestinal dysbiosis
| Bacterial activity: bile salt deconjugation, fatty acid hydroxylation, competition for cobalamin and nutrients |
Mucosal | Infectious enteropathies
Chronic inflammatory enteropathy
Neoplastic infiltration | Mucosal damage: inflammation, brush border defects, disturbed enterocyte function, reduction of surface area |
Mucosal | Villous atrophy | Reduction in surface area, immature enterocytes due to increased cell turnover with reduced brush border enzyme expression |
Mucosal | Inherited and acquired brush border enzyme deficiencies | Lactase deficiency, diffuse small-intestinal disease |
Postmucosal | Lymphangiectasia | Lymphatic obstruction impairs delivery of chylomicrons |
Postmucosal | Vasculitis, portal hypertension | Impaired delivery |