Malabsorption Flashcards
Iron is absorbed in the duodenum
B12 needs intrinsic factor from the stomach for absorption
bile salts are absorbed in the terminal ileum
Other symtpoms of global malabsorption
Borborygmi= hearing gut sounds
What are some gastric causes of malabsorption?
- atrophic gastritis
- autoimmune gastritis (pernicious anemia)
- gastric resection
What are some pancreatic causes of malabsorption?
What are some endocrine causes of malabsorption?
- Addison’s disease
- Diabetes
- Hypothyroidism
If you suspect malabsorption, start with an H&P
What labs should you get for a suspected malabsorptive pt?
–CBC (are they anemic or macro/microcytic)
–Iron, B12, Folate
–Albumin
–Calcium / Vit D
•Malabsorption of ____ is most commonly used indicator of global malabsorption
fat
Why is fat the best indicator for global malabsorption?
(1) among the macronutrients (fat, carbohydrates, and protein), the process by which fat is absorbed is the most complex and, therefore, it tends to be the most sensitive to interference from disease processes; and
(2) it is the most calorically dense macronutrient and, therefore, its malabsorption is a critical factor in the weight loss that often accompanies malabsorptive disorders.
How is fat malabsorption assessed?
Via a stool fat assessment. In healthy people, stool fat excretion is usually less than 6 gram daily (Stool fat remains constant with high fat diets, even greater than 125 grams fat daily). This can be increased in patients with are having diarrhea
Typically the diagnosis of steatorrhea requires 20+gm of fat/24hr
What are some qualitative ways to measure steatorrhea?
- 72 hour stool collection is cumbersome and messy
- A Sudan stain for fat globules from a spot stool sample can detect > 90% of patients with steatorrhea (below)
How can you test for carbohydrate malabsorption?
–Can rely on fermentation of undigested carbohydrates by intestinal bacteria
–Or direct measurement of the absorption of specific nutrients after a test dose (Examples are the lactose tolerance test as well as several breath tests, which measure hydrogen or radioactive isotopes from sugars containing radionuclide carbon analogues.)