Chapter 66- Hypoglycemia Flashcards
What 3 sources does glucose come from?
- Intestinal absorption from digestion of carbohydrates
- Breakdown of the storage for of glucose (glycogen) via glycogenolysis
- Production of glucose from precursors - lactate, pyruvate, AA and glycerol via gluconeogenesis
Insulin is secreted from the beta cells of the pancreas in response to?
- Hyperglycemia
- Amino acids
- GI hormones
What does insulin do?
- Glucogneogenesis
- Glycogenolysis
- Promote glycogen storage
- Stimulates glucose uptake and utilization by insulin-sensitive cells
- Decreases glucagon secretion
Low BG causes release of which 4 counter-regulatory hormones?
- Glucagon
- Epi
- Cortisol
- Growth hormone
What cells secrete glucagon?
Pancreatic ALPHA cells
Glucagon
- Directly stimulates hepatic glycogenolysis and gluconeogenesis
- Mobilizes gluconeogenic precursors
- Reduces peripheral glucose utilization
Epinephrine
- Limits insulin secretion
- Increases glucagon secretion
Cortisol
- Increases glucose-fascilitating lipolysis
- Release of amino acids from muscle for gluconeogenesis in the liver
Growth hormone
- Antagonizes effects of insulin by decreasing peripheral glucose utilization
What are the 4 mechanisms of hypoglycemia?
- Inadequate dietary intake (not on own - combined with the other 3)
- Excessive glucose utilization
- Dysfunctional glycogenolytic or gluconeogenic pathways
- Endocrine abnormalities
4 broad categories of hypoglycemia?
- Artifact
- Excess insulin
- Excess glucose utilization
- Decreased glucose production
What are the 3 artifacts?
- Pseudohypoglycemia
- Handheld glucometer
- Hemoconcentration
What are 4 broad categories for excess insulin or insulin analogs for hypoglycemia?
- Exogenous insulin overdose
- Insulinoma
- Paraneoplastic syndromes
- Toxins and medications
What are the cancers that cause paraneoplastic hypoglycemia? (besides insulinoma)
- Hepatomas, hepatocellular carcinoma
- Leiomyomas, leiomyosarcomas
- Pulmonary, mammary and salivary carcinomas
- Lymphoma, plasmacytoid tumors
- Oral melanoma, HSA
2 toxins that cause hypoglycemia
- Xylitol
2. Sulfonylureas
What 6 things can cause excess glucose utilization?
- Infection - sepsis, babesia
- Exercise-induced hypoglycemia (hunting dogs)
- Paraneoplastic
- Polycythemia
- Leukocytosis
- Pregnancy
What 6 things cause decreased glucose production?
- Neonatal hypoglycemia
- Hepatic dysfunction
- Addison’s
- Counter-regulatory hormone deficit
- Glycogenic or gluconeogenic enzyme deficiencies
- Beta blockers
Amended insulin/glucose ration (AIGR) calculation
AIGR= (insulin x 100)/(plasma glucose - 30)
For the AGIR calculation, a denominator of ___ is used if the BG is less than 30 g/dL?
1
An AGIR higher than ___ suggests insulinoma ?
30
Is the AGIR calculation definitive?
No
Approximately what % of patient with insulinoma already have metastatic disease?
50%
Diazoxide
Directly inhibits pancreatitic insulin secretion
Streptozocin
Selectively destroys pancreatic BETA cells
