Lecture 20 11/21/24

Question 1

Which glucose monitoring instruments use whole blood as a sample?

Answer 1

-glucometer
-blood gas instrument

Question 2

Which glucose monitoring instrument uses plasma or serum as a sample?

Answer 2

chem analyzer

Question 3

Which glucose monitoring instrument uses interstitial fluid as a sample?

Answer 3

freestyle libre style monitors

Question 4

What are the characteristics of glucose in the blood?

Answer 4

-glucose is dissolved in the aqueous fraction of blood
-cell cytosol contains less water than plasma
-more glucose is found in the plasma than the RBC cytosol
-a given volume of whole blood contains less glucose than the same volume of plasma

Question 5

What are the characteristics of modern glucometers?

Answer 5

-measure glucose in whole blood
-assume normal PCV and normal distribution of glucose in RBCs and plasma
-covert whole blood glucose to plasma-equivalent glucose via calculation

Question 6

Why is it important to use veterinary glucometers?

Answer 6

human glucometers have been known to provide falsely low results for animals

Question 7

When should glucometers NOT be used?

Answer 7

-patients with abnormal PCV; inaccurate results
-effusions; falsely high glucose

Question 8

What should be done to minimize pre-analytical error?

Answer 8

separate plasma or serum from cells ASAP; separates glucose from the cells that will continue to use glucose until they die

Question 9

What are the characteristics of glucose on urine dipstick?

Answer 9

-glucose is freely filtered and reabsorbed
-glucosuria can occur if resorption mechanism is overwhelmed or tubular damage/defect is present

Question 10

What are the mechanisms of hyperglycemia?

Answer 10

-increased intestinal absorption
-catecholamine release
-increased gluconeogenesis/glycogenolysis
-absolute insulin deficiency
-increased insulin resistance
-impaired insulin release
-excess growth hormone
-excess glucagon
-pharmacologic

Question 11

What are the characteristics of glucose in llamas and alpacas?

Answer 11

-hyperglycemia common when sick
-presumed that hyperglycemia is due to stress hormone release and insulin resistance
-may require insulin treatment, especially with marked abnormalities

Question 12

What are the mechanisms of hypoglycemia?

Answer 12

-pre-analytical error
-insulin excess
-decrease in insulin antagonists
-decreased gluconeogenesis
-decreased glycogenolysis
-increased tissue utilization of glucose
-pharmacologic
-paraneoplastic

Question 13

Which patients are predisposed to hypoglycemia during fasting?

Answer 13

-patients undergoing starvation/cachexia
-neonates/juveniles with immature liver
-patients with liver disease

Question 14

Which ketones are of medical importance?

Answer 14

-acetoacetate
-acetone
-beta-hydroxybutyrate

Question 15

When are ketones measured?

Answer 15

-as part of routine urine dipstick test
-when diabetes mellitus is suspected
-when negative energy balance is suspected

Question 16

Which samples are typically used to measure ketones?

Answer 16

-urine
-milk

Question 17

What is the pathogenesis of ketosis?

Answer 17

-high metabolic energy demand + carb poor diet OR insulin lack/resistance
-fats catabolized for energy
-ketones accumulate

Question 18

What are the components of ketosis?

Answer 18

-ketonemia
-ketonuria
-ketonlactia

Question 19

What is the consequence of ketosis?

Answer 19

can lead to titrational metabolic acidosis with a high AG

Question 20

What are the characteristics of beta-hydroxybutyrate?

Answer 20

-not detected on urine dipstick
-must be measured using a BHB meter or via referral lab

Question 21

What are the causes of ketosis?

Answer 21

-untreated or poorly regulated diabetes mellitus
-diabetic ketoacidosis
-hypoglycemia of lactation or pregnancy with inadequate carb intake
-endurance athletes with inadequate carb intake

Question 22

What are the characteristics of ketosis with hyperglycemia?

Answer 22

-think diabetes mellitus
-form of chronic negative energy balance due to insulin lack
-body starves because cells cannot utilize glucose without insulin
-classic findings are PU/PD, polyphagia, and weight loss
-PU/PD due to osmotic diuresis

Question 23

What are the characteristics of ketosis with hypoglycemia?

Answer 23

-think excess energy demand
-happens when there are inadequate carbs in diet
-occurs with lactational hypoglycemia, pregnancy hypoglycemia, and endurance athletes

Question 24

What is the pathogenesis of milk fever/parturient paresis in cattle?

Answer 24

-lactation leads to calcium loss
-calcium loss results in hypocalcemia
-hypocalcemia impairs insulin activation
-hyperglycemia occurs
-hyperglycemia can be exacerbated by stress

Question 25

What is the pathogenesis of lactational hypoglycemia in cattle?

Answer 25

-poor feed quality or decreased food intake during lactation leads to increased tissue demand for glucose -liver cannot keep up with tissue glucose demand -hypoglycemia and ketosis occur

Question 26

What is the pathogenesis of pregnancy hypoglycemia in sheep?

Answer 26

-poor feed quality or decreased food intake when carrying twins leads to increased tissue demand for glucose -liver cannot keep up with tissue glucose demand -hypoglycemia and ketosis occur

Question 27

What are the characteristics of fructosamine?

Answer 27

-protein, typically albumin, irreversibly binds to glucose -reflects blood glucose over the lifespan of the albumin molecule -measured in serum -increased with sustained hyperglycemia

Question 28

How is fructosamine used in vet med?

Answer 28

-helps determine if hyperglycemia is transient and due to stress or caused by true diabetes mellitus -used to monitor response to insulin treatment in diabetics -increased fructosamine suggests prolonged hyperglycemia

Question 29

What causes increased fructosamine?

Answer 29

persistent hyperglycemia/diabetes mellitus

Question 30

What causes decreased fructosamine?

Answer 30

-persistent hypoglycemia -hypoproteinemia/hypoalbuminemia

Question 31

What are the characteristics of medically important lipids?

Answer 31

-cholesterol, triglycerides, and NEFAs are commonly measured -no routine tests to measure various lipoprotein classes, such as LDL vs HDL -increased conc. of lipid in plasma referred to as hyperlipidemia, hyperlipemia, or hyperlipoproteinemia

Question 32

What are the characteristics of cholesterol?

Answer 32

-cholesterol readout on biochem panel is total cholesterol; HDL + LDL + VLDL -measured in plasma or serum -measured in mg/dL -ideally measured in a fasted sample

Question 33

What are the characteristics of triglycerides?

Answer 33

triglyceride readout on biochem panel is chylomicron + VLDL -in fasting sample, TG = mostly VLDL -in post-prandial sample, TG = mostly chylomicron -measured in plasma or serum -measured in mg/dL -ideally measured in a fasted sample

Question 34

What are the potential causes of lipemia?

Answer 34

-not fasting patient (error) -endocrine disease --idiopathic hyperlipidemia -pancreatitis

Question 35

What is the visible appearance of lipemia?

Answer 35

opaque, white, milky plasma or serum

Question 36

What are the characteristics of lipemia as an interferent?

Answer 36

falsely increases: -total protein -hemoglobin -MCH/MCHC

Question 37

What are the characteristics of lipemia handling in lab?

Answer 37

-labs prevent lipemia from interfering with sample readouts by running samples through ultrafugation -need to tell labs not to do ultrafugation when trying to do a medical assessment of tryglycerides

Question 38

What are the characteristics of the lipemia refrigeration test?

Answer 38

-crude assessment of chylomicron presence -positive test will have formation of a cream layer

Question 39

Which disorders always cause hypercholesterolemia?

Answer 39

-cholestasis -hyperadrenocorticism -hypothyroidism -protein-losing nephropathy

Question 40

Which disorders always cause hypertriglyceridemia?

Answer 40

-acute pancreatitis -anorexia in obese animals -diabetes mellitus -equine metabolic syndrome -post-prandial

Question 41

Which disorders cause low cholesterol?

Answer 41

-hepatic insufficiency -protein-losing enteropathy -hypoadrenocorticism -certain cancers

Question 42

What are the characteristics of NEFAs/FFAs?

Answer 42

-biomarker of negative energy balance -measured in plasma or serum -measured in mEq/mL -typically measured in dairy cattle; increased NEFAs suggests need for better management