GI Clin Path

Question 1

what are the 3 components of routine ancillary analysis of the GI system?

Answer 1

1. folate (vitamin B9)
2. cobalamin (vitamin B12)
   2a. methylmalonic acid
3. fecal alpha-1 protease inhibitor

Question 2

describe the sources of B9 (folate) and cobalamin (B12); where are they absorbed?

Answer 2

folate is from the diet and microbes; absorbed in the jejunum

cobalamin is also from the diet and absorbed later in the ileum (seCond)

Question 3

what can hyperfolatemia indicate? (3)

Answer 3

1. increased synthesis by bacteria
2. iatrogenic: supplementation
3. hemolysis

Question 4

what can hypofolatemia indicate? (2)

Answer 4

1. decreased absorption in the jejunum
2. hypocobalaminemia (cobalamine needed to convert folate to active form)

Question 5

what can hypercobalaminemia indicate?

Answer 5

iatrogenically: supplementation

Question 6

what can hypocobalaminemia indicate?

Answer 6

decreased absorption in the ileum due to severe small intestinal disease or increased binding by bacteria in the small intestine

Question 7

what is methylmalonic acid?

Answer 7

a marker for cobalamin deficiency on a cellular level; cobalamin deficiency favors MMA production

Question 8

describe alpha-1 protease inhibitor (where found what indicated if increased (3))

Answer 8

normally found in plasma, interstitial fluid, and lymph, NOT in intestinal lumen!!

if increased, can indicate:
1. protein-losing enteropathy
2. blood loss/hemorrhage into the GI tract
3. blood contamination (if poke too hard with fecal loop)

Question 9

how are lipids transported in the blood? what are the sources?

Answer 9

as lipid-protein complexes from hepatocytes and small intestinal enterocytes

Question 10

describe biochemical analysis of plasma lipids (3) what does hyperlipidemia mean?

Answer 10

1. triglycerides (chylomicrons and VLDLs): use a fasted sample; have gross lipemia if greater than 200mg/dL that can interfere with other blood tests
2. cholesterol (LDL, HDL)
3. non-esterified fatty acids

hyperlipidemia: increased serum triglycerides and/or cholesterol

Question 11

what does hyperlipidemia indicate? (2)

Answer 11

1. increased production/absorption (can occur after a meal)
2. decreased lipidosis or lipoprotein processing

Question 12

what does hypolipidemia indicate? (2)

Answer 12

1. decreased production (in the liver) or absorption (in the ileum); can indicate GI or liver disease
2. altered metabolism/uptake

Question 13

what is the source of NEFAs? (3)

Answer 13

1. hepatic lipidosis
2. adipocytes
3. mammary tissue

Question 14

what does a negative energy balance cause in terms of NEFAs?

Answer 14

negative energy balance causes increased lipolysis, meaning triglycerides in adipose are converted to NEFAs and sent to the liver, where they are converted to ketones (causing ketosis) or VLDL; if hepatocytes are overwhelmed by converting triglycerides to VLDL to hepatic lipidosis

Question 15

what are the 2 important proteins analyzed in the GI tract? describe

Answer 15

1. albumin: synthesized in the liver; in plasma; responsible for 80% colloid osmotic pressure
2. globulins: all proteins in serum other than albumin; alpha and beta are synthesized by the liver; gamma are immunoglobulins and made by B lymphocytes and plasma cells

Question 16

what does hyperalbuminemia indicate?

Answer 16

hemoconcentration (dehydration)

Question 17

what does hyperglobulinemia indicate? (2)

Answer 17

1. hemoconcentration (dehydration)
2. increased globulin synthesis (inflammation or neoplasia)

Question 18

what can hypoproteinemia indicate? (4)

Answer 18

1. increased protein loss
2. decreased protein synthesis or increased protein catabolism
3. failure of passive transfer (of foals/calves via colostrum)
4. hemodilution: iatrogenic, edematous diseases

Question 19

what are the 2 types of protein loss? describe

Answer 19

nonselective/panhypoproteinemia: due to blood loss or protein losing enteropathy
selective (decreased albumin):

Question 20

what can result in abnormal electrolytes in blood?

Answer 20

1. changes in free water
2. decreased or increased intake
3. shifts to and from ICF
4. increased renal retention
5. increased loss via kidneys, GI tract, skin, or airways (5)