Definition
Defective absorption of nutrients.
- Most commonly manifests as chronic diarrhea
- Steatorrhea -- Diarrhea with excessive amounts of fat
- Results in weight loss, vitamin deficiencies, muscle wasting, borborygmi (grumbling sounds and hunger pangs)
Etiology
The cause of the malabsorption depends on the chemical/anatomical step of absorption being defected:
- Intraluminal digestion -- Breaking down of macronutrients (carbohydrates, fats, proteins) within the lumen of the GIT
- Terminal digestion -- Further breakdown of micronutrients (disaccharides, peptides) in the brush border of enterocytes
- Transepithelial transport -- Transport of fluid and nutrients across the enterocytes
- Lymphatic transport -- Transport of chylomicrons to the lymphatic system