Small intestine

Question 1

Malabsorption

Answer 1

Inadequate intestinal absorption that can be specific or multiple nutrients

Question 2

Causes of malabsorption

Answer 2

-Dysfunctional enterocytes
-Loss or reduced absorptive surfaces
-Intestinal mucosal infiltration

Question 3

Tests for small intestine function

Answer 3

-Cobalamin (B12)
-Folate (B9)

Question 4

Cobalamin

Answer 4

Water soluble often obtained from food. It is mainly absorbed in the ileum (receptor mediated)and a small amount is passively diffused. Essential cofactor for enzymatic process, intestinal epithelial function, CNS maintenance, hematopoiesis

Question 5

Cbl absorption in monogastric

Answer 5

Bound to dietary protein in the stomach and is then disassociated and binds to R protein and travels to the proximal SI and dissociates and rebinds to intrinsic factor-> then v=binds to receptor in distal SI and binds to transcobalamin and is now in the blood-> enters enterohepatic circulation

Question 6

Assays for Cbl

Answer 6

GI panels measure serum usually a competitive binding assay
Do not expose to light and prefer serum

Question 7

Cbl in ruminants

Answer 7

Produced by rumen bacteria and metabolism after similar to SA

Question 8

When to measure CBL

Answer 8

-EPI
-Chronic GI disease
-Failure to thrive
-Neurological disorders (increased ammonia in plasma)
-Anemias/neutropenia

Question 9

Increased Cbl

Answer 9

Uncommon
-Supplementation
-Hepatic parenchymal damage (storage site of Cbl)

Question 10

Decreased Cbl

Answer 10

-EPI
-SI bacterial overgrowth
-Decreased absorption due to intestinal disease
-Congenital conditions

Question 11

Folate

Answer 11

Water soluble from diet that is absorbed in the jejunum and is used for DNA synthesis. Stored in RBC

Question 12

Folate metabolism

Answer 12

Folate polyglutamate in stomach gets deconjugated ontp folate monoglutamate by folate deconjugase, that then allows for them to bind to receptors and they are absorbed

Question 13

Folate assays

Answer 13

Competitive binding (antibodies) using serum often done with Cbl

Question 14

Increased folate

Answer 14

-Increased absorption ( EPI, SIBO, Increased oral intake, increased gastric acid secretion)
-Parenteral supplementation
-Cbl deficiency in cats
-Hemolysis

Question 15

Decreased folate

Answer 15

-Decreased absorption of folate
-Dietary deficiency
-Medications, intestinal sterilization, extensive neoplasia