Hypoglycemia (SACCM) Flashcards

1
Q

Cite three sources of glucose

A
  1. Intestinal absorption from digestion of carbohydrates
  2. Breakdown of the storage form (glycogen) via glycogenolysis
  3. Production of glucose from precursos: Lactate, aa, pyruvate and glycerol, via gluconeogenesis
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2
Q

List hormones that elevate the concentration of glucose in plasma

A

Glucagon
Epinephrine
Cortisol
Growth hormone

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3
Q

What are the stimulants of insuline secretion from the B cells in the pancreas

A
  1. Increased concentrations of glucose after a meal
  2. increased concentrations of aminoacids after a meal
  3. increased GI hormones: gastrin, secretin, cholecystokinin and specially gastric inhibitory peptide
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4
Q

What are the precursors of glucose

A

Lactate, pyruvate, amino acids and glycerol (gluconeogenesis)

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5
Q

Describe the inhibitory function of insulin (3)

A

Insulin inhibits gluconeogenesis, glycogenolysis and decreases glucagon secretion

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6
Q

Describe the stimulatory function of insulin (5)

A
  • It promotes glycogen storage
  • stimulates glucose uptake
  • Utilization by insulin - sensitive cells
  • promotes tryglyceride formation in adipose tissue
  • Promotes the synthesis of protein and glycogen in muscle
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7
Q

What hormones are released in the event of hypoglycemia? Specify the timeline

A

Epinephrine, glucagon, cortisol and growth hormone
- Epi and glucagon within minutes and have a transient effect
- Cortisol ahd GH within few hours and have a longer lasting effect up to 12 hours

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8
Q

Which cells secrete glucagon?

A

Pancreatic alpha cells

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9
Q

Functions of glucagon (4)

A

It acts on the liver to:
1. stimulate hepatic glycogenolysis
2. and gluconeogenesis
3. mobilizes gluconeogenic precursors
4. reduces peripheral glucose utilization

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10
Q

Give 2 effects for each hormone regarding glucose homeostasis:
Epinephrine, cortisol and growth hormone

A

Epinephrine:
- limits insulin secretion
- increases glucagon secretion
Cortisol:
- increases glucose facilitating lipolysis
- release of aminoacids from the muscle for gluconeogenesis in the liver
Growth hormone antagonizes effects of insulin by
- decreasing peripheral glucose
- and promoting lipolysis

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11
Q

What are the 4 mechanisms of hypoglycemia

A
  1. Inadequate dietary intake (requires another mechanism)
  2. excessive glucose utilization
  3. dysfunctional glycogenolytic, gluconeogenic pathways or inadequate precursors for these pathways.
  4. endocrine abnormalities
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12
Q

Which organ relies the most on glucose? what are the clinical manifestations

A

The brain, neuroglycopenia
dullness/obtundation, weakness, ataxia, seizures, blindness

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13
Q

Causes of hypoglycemia (at least 10!)

A
  • Artifact: hemoconcentration
  • Excess insulin (or analogus)
    • exogenous overdose
    • Insulinoma
    • Pareneoplastic syndrome
    • Toxins or meds
  • Excess utilization
    • Infection
    • Exercise
    • polycytemia
    • leukocytosis
    • pregnancy
    • exercise induced
  • Decreased glucose products
    • Neonatal
    • Hepatic dysfunction
    • Hypocortisolism
    • Hormone deficiencies: glucagon, GF,
      thyroid horm, cathecolamines,
      hypopituitarism
    • Glycogenic or gluconeogenic enz
      deficiencies
    • Beta blockers
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14
Q

What percentage of hepatic function is enough to maintain euglycemia ?

A

Approximately 30% ( you need to lose 70% of function to show signs of hypoglycemia)

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15
Q

Mechanism of hypoadrenocorticism related hypoglycemia

A

Loss of cortisol induced counterregulatory mechanisms:
- increases glucose facilitating lipolysis
- release of aminoacids from the muscle for gluconeogenesis in the liver

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16
Q

Drugs for medical managment of persistent hypoglycemia (chronic) due to insulinoma:
1. Med – MOA
2. Med – MOA
… (5)

A
  1. Prednisone: cortisole analogus
  2. Diazoxide: inhibits pancreatic insulin secretion
  3. Streptozocin: selectively destroys the B cells of the pancreas
  4. Octreotide (somatostatin analogus ): suppresses synthesis and secretion of insulin.
  5. Alloxan: Beta cell cytotoxin