Endocrinology - Glucose homeostasis...

Question 1

Glucose is the sole source of energy for the ________.

Answer 1

brain

Question 2

What is the range for normal blood glucose?

Answer 2

70-120 mg/dl

Question 3

What are the exogenous sources of glucose?

Answer 3

intestinal absorption

Question 4

What are the endogenous sources of glucose?

Answer 4

glycogenolysis and gluconeogenesis

Question 5

Post-prandially, how long does glucose provide fuel for and for what?

Answer 5

fuel for 4-8 hours of cell metabolism

Question 6

In the fasted state, what sources maintain normoglycemia?

Answer 6

The endogenous sources

Question 7

What is glycogenolysis?

Answer 7

breakdown of hepatic glycogen stores into glucose

Question 8

When are the hepatic glycogen stores exhausted during fasting?

Answer 8

after 2-3 days of fasting

Question 9

When glycogen stores are depleted in fasted patients, what takes over to maintain normoglycemia?

Answer 9

gluconeogenesis

Question 10

What is gluconeogenesis?

Answer 10

The formation of glucose from precursors

Question 11

What are the precurosors for gluconeogenesis?

Answer 11

Amino acids, glycerol, and lactate

Question 12

Where does gluconeogenesis occur?

Answer 12

Mainly in the liver, but it can also occur in the kidney

Question 13

Aside from the exogenous and endogenous sources of glucose, what is also required for normoglycemia?

Answer 13

hepatic function/hepatic blood supply and a functioning endocrine system

Question 14

What does insulin do?

Answer 14

Promote the cellular uptake of glucose, AA, FA, and electrolytes
Promotes the storage of glucose as glycogen
Inhibits lipolysis and subsequent release of FFA into circulation
Inhibits gluconeogenesis and glycogenolysis

Question 15

Hypoglycemia is when BG falls below what level?

Answer 15

70 mg/dl

Question 16

What is the normal response to hypoglycemia?

Answer 16

There is a stimulation of a release of diabetogenic hormones - glucagon, cortisol, catecholamines, and growth hormone (unimportantly progesterone and thyroxine too)

Question 17

What is the net effect of the diabetogenic hormones?

Answer 17

Promote gluconeogenesis and glycogenolysis, decrease peripheral glucose use, and shut down insulin secretion

Question 18

What is the net result of the effect of diabetogenic hormones?

Answer 18

to normalize blood glucose levels

Question 19

What hormones increase BG?

Answer 19

cortisol, epinehrine, glucagon, and growth hormone

Question 20

What hormone decreases BG?

Answer 20

insulin

Question 21

What can cause hypoglycemia?

Answer 21

Lack of intestinal absorption, lack of hepatic production, endocrine disorders, increased glucose utilization, and miscellaneous

Question 22

What can cause lack of intestinal absorption of glucose?

Answer 22

severe malnutrition/starvation and severe intestinal disease

Question 23

What can cause lack of hepatic production of glucose?

Answer 23

Portosystemic shunts, hepatic failure, and glycogen storage diseases

Question 24

What are the sub-categories of endocrine disorders can cause hypoglycemia?

Answer 24

Lack of diabetogenic hormones or too much insulin

Question 25

What endocrine disorders can cause lack of diabetogenic hormones?

Answer 25

hypoadrenocorticism - cortisol deficiency

Question 26

What endocrine disorders can cause the production of too much insulin?

Answer 26

iatrogenic and insulinoma

Question 27

What can cause increased glucose utilization?

Answer 27

sepsis, pollycythemia, and extreme exertion

Question 28

What miscellaneous causes can lead to hypoglycemia?

Answer 28

Juvenile hypoglycemia, xylitol toxicity, paraneoplastic, and artifact

Question 29

What is the pneumonic to remember the eitiologies for hypoglycemia?

Answer 29

SHIN SPLATS - Sepsis, Hunting dog hypoglycemia, Insulin overdose/iatrogenic, Neoplasia, Spurious, Puppy or polycythemia, Liver disease, Addison's disease, Toxin, and Storage diseases

Question 30

What is the first area affected by hypoglycemia?

Answer 30

the cerebral cortex

Question 31

Clinical signs from hypoglycemia in the brain result from what?

Answer 31

Neuroglycopenia and sympathoadrenal stimulation

Question 32

What is neuroglycopenia?

Answer 32

lack of glucose to the brain

Question 33

What is sympathoadrenal stimulation?

Answer 33

The release of epinephrine as a result of hypoglycemia

Question 34

What are the clinical signs of neuroglycopenia?

Answer 34

weakness, lethargy, behavioral change, ataxia, seizures, and coma

Question 35

What are the clinical signs associated with sympathoadrenal stimulation?

Answer 35

Think of someone that is hangry - muscle tremors, nervousness, restlessness, and hunger

Question 36

What is an insulinoma?

Answer 36

A tumor of pancreatic beta cells that autonomously secretes insulin

Question 37

Insulinomas are common in _____, uncommon in ______, and rare in _______.

Answer 37

ferrets, dogs, and cats

Question 38

What breed of dog is over-represented in insulinomas? Age of diagnosis?

Answer 38

Large breeds are over-represented and average age is 9-10 years

Question 39

Are the majority of insulinomas benign or malignant?

Answer 39

malignant

Question 40

What is the behaviorof insulinomas?

Answer 40

Chronic, insidious onset - at the time of diagnosis a majority of them metastasize

Question 41

How may patients with insulinomas present?

Answer 41

They may have severe hypoglycemia with relatively mild clinical signs

Question 42

How are insulinomas diagnosed?

Answer 42

By demonstrating high insulin with concurrent low glucose - you must measure insulin when BG is low (i.e. prior to stabilization of the patient)

Question 43

If BG is <50 mg/dl and insulin is above the reference range, what is the likelihood that the cause is due to an insulinoma?

Answer 43

a high probability

Question 44

If BG is <50 mg/dl and insulin is low, what is the chance that an insulinoma is the cause?

Answer 44

it should be ruled out

Question 45

If the insulin:glucose ratio is greater than 30, what should you suspect?

Answer 45

hyperinsulinemia

Question 46

What is the recommended emergency therapy for hypoglycemia?

Answer 46

IV catheter, 50% dextrose solution, and Administer glucose slowly over 10 minutes

Question 47

Why do we want to treat for clinical signs associated with hypoglycemia and not the number?

Answer 47

Because if the reason for hypoglycemia is due to an insulinoma, the increase in BG will promote insulin release ultimately worsening the hypoglycemia

Question 48

What some alternative options to using glucose to treat hypoglycemia?

Answer 48

glucagon and dexmedetomidine CRI

Question 49

Why would you want to give dexmedetomidine to treat hypoglycemia?

Answer 49

it antagonizes insulin

Question 50

When is hyperglycemia a normal finding?

Answer 50

2-4 hours post prandial - it is mild

Question 51

What are the etiologies of hyperglycemia?

Answer 51

Too much of one (or more) hormones that raise BG, deficiency in hormone that decreases BG, and miscellaneous

Question 52

What hormones can cause hyperglycemia if they are in excess?

Answer 52

cortisol, growth hormone, epinephrine, glucagon, and progesterone

Question 53

True or False: If there is excess of a hormone, hyperglycemia is not usually the sole clinical presentation.

Answer 53

TRUE

Question 54

When is therapy for hyperglycemia indicated?

Answer 54

Usually only if diabetes develops as a complication of the primary endocrine disease

Question 55

What are the sources of stress hyperglycemia?

Answer 55

Catecholamine release and glucocorticoids

Question 56

What is the renal threshold for glucose in dogs?

Answer 56

180 mg/dl

Question 57

What is the renal threshold for glucose in cats?

Answer 57

280 mg/dl

Question 58

What disease process that is due to low insulin can cause hyperglycemia?

Answer 58

Diabetes mellitus

Question 59

What is the pathophysiology of insulin deficiency in diabetes mellitus?

Answer 59

There is decreased tissue utilization of glucose, increaed hepatic glycogenolysis and gluconeogenesis, and then the glucose from the liver accumulates in the circulation resulting in hyperglycemia

Question 60

How does hyperglycemia in diabetes mellitus patients lead to glucosuria?

Answer 60

The high glucose levels exceeds renal tubular reabsorptive abilities

Question 61

How does hyperglycemia in diabetes mellitus patients lead to polyuria?

Answer 61

It causes osmotic diuresis

Question 62

Why does polydipsia follow polyuria in diabetes mellitus patients?

Answer 62

it is a compensatory mechanism to prevent dehydration

Question 63

Why does polyphagia occur in the face of hyperglycemia in diabetes mellitus patients?

Answer 63

Normally, the satiety center inhibits the feeding center after a meal. In order to do this, the satiety center requires insulin for glucose transport. When insulin is defficent, glucose does not enter the satiety center and therefore fails to inhibit the feeding center. Polyphagia is the result

Question 64

What are the clinical signs of diabetes mellitus?

Answer 64

polyuria, polydipsia, polyphagia, and weight loss

Question 65

How is diabetes mellitus diagnosed?

Answer 65

Resting hyperglycemia with glucosuria in an animal with compatible clinical signs