Chapter 66- Hypoglycemia

Question 1

What 3 sources does glucose come from?

Answer 1

1. Intestinal absorption from digestion of carbohydrates
2. Breakdown of the storage for of glucose (glycogen) via glycogenolysis
3. Production of glucose from precursors - lactate, pyruvate, AA and glycerol via gluconeogenesis

Question 2

Insulin is secreted from the beta cells of the pancreas in response to?

Answer 2

• Hyperglycemia
• Amino acids
• GI hormones

Question 3

What does insulin do?

Answer 3

• Glucogneogenesis
• Glycogenolysis
• Promote glycogen storage
• Stimulates glucose uptake and utilization by insulin-sensitive cells
• Decreases glucagon secretion

Question 4

Low BG causes release of which 4 counter-regulatory hormones?

Answer 4

1. Glucagon
2. Epi
3. Cortisol
4. Growth hormone

Question 5

What cells secrete glucagon?

Answer 5

Pancreatic ALPHA cells

Question 6

Glucagon

Answer 6

• Directly stimulates hepatic glycogenolysis and gluconeogenesis
• Mobilizes gluconeogenic precursors
• Reduces peripheral glucose utilization

Question 7

Epinephrine

Answer 7

• Limits insulin secretion

- Increases glucagon secretion

Question 8

Cortisol

Answer 8

• Increases glucose-fascilitating lipolysis

- Release of amino acids from muscle for gluconeogenesis in the liver

Question 9

Growth hormone

Answer 9

• Antagonizes effects of insulin by decreasing peripheral glucose utilization

Question 10

What are the 4 mechanisms of hypoglycemia?

Answer 10

1. Inadequate dietary intake (not on own - combined with the other 3)
2. Excessive glucose utilization
3. Dysfunctional glycogenolytic or gluconeogenic pathways
4. Endocrine abnormalities

Question 11

4 broad categories of hypoglycemia?

Answer 11

1. Artifact
2. Excess insulin
3. Excess glucose utilization
4. Decreased glucose production

Question 12

What are the 3 artifacts?

Answer 12

1. Pseudohypoglycemia
2. Handheld glucometer
3. Hemoconcentration

Question 13

What are 4 broad categories for excess insulin or insulin analogs for hypoglycemia?

Answer 13

1. Exogenous insulin overdose
2. Insulinoma
3. Paraneoplastic syndromes
4. Toxins and medications

Question 14

What are the cancers that cause paraneoplastic hypoglycemia? (besides insulinoma)

Answer 14

• Hepatomas, hepatocellular carcinoma
• Leiomyomas, leiomyosarcomas
• Pulmonary, mammary and salivary carcinomas
• Lymphoma, plasmacytoid tumors
• Oral melanoma, HSA

Question 15

2 toxins that cause hypoglycemia

Answer 15

1. Xylitol

2. Sulfonylureas

Question 16

What 6 things can cause excess glucose utilization?

Answer 16

1. Infection - sepsis, babesia
2. Exercise-induced hypoglycemia (hunting dogs)
3. Paraneoplastic
4. Polycythemia
5. Leukocytosis
6. Pregnancy

Question 17

What 6 things cause decreased glucose production?

Answer 17

1. Neonatal hypoglycemia
2. Hepatic dysfunction
3. Addison’s
4. Counter-regulatory hormone deficit
5. Glycogenic or gluconeogenic enzyme deficiencies
6. Beta blockers

Question 18

Amended insulin/glucose ration (AIGR) calculation

Answer 18

AIGR= (insulin x 100)/(plasma glucose - 30)

Question 19

For the AGIR calculation, a denominator of ___ is used if the BG is less than 30 g/dL?

Answer 19

1

Question 20

An AGIR higher than ___ suggests insulinoma ?

Answer 20

30

Question 21

Is the AGIR calculation definitive?

Answer 21

No

Question 22

Approximately what % of patient with insulinoma already have metastatic disease?

Answer 22

50%

Question 23

Diazoxide

Answer 23

Directly inhibits pancreatitic insulin secretion

Question 24

Streptozocin

Answer 24

Selectively destroys pancreatic BETA cells

Question 25

Octreotide

Answer 25

Somatostatin analog

Question 26

Mean survival time for insulinoma with medical management only?

Answer 26

• 74 days

- 196 days