Hypoglycemic States Flashcards
What are the six hormones that increase BG?
- Glucagon
- Cortisol
- GH
- Epi
- NE
What is the molecule that is needed to convert pyruvate to lactate?
NADH
What is the effect of leptin? Ghrelin?
Leptin decreases appetite
Ghrelin increases appetite
What is the effect of insulin on serum [K]?
Decreases d/t increased uptake by cells
What happens to the adrenergic system with hypoglycemia? What, then, are the ssx of hypoglycemia?
Increases
- Diaphoresis
- Tachycardia
- Anxiety
What is the satiety center of the brain?
Ventromedial nucleus of the hypothalamus
What is the thirst/cooling center of the brain?
Anterior hypothalamus
What is the heating center of the brain?
Posterior hypothalamus
What is the hunger center of the brain?
Lateral hypothalamus
What are the most common causes of hypoglycemia in adults?
- EtOH
- Sepsis
- Adrenal insufficiency
How can EtOH cause hypoglycemia? (2)
- EtOH metabolism reduces the amount of NADH, which is needed for the conversion of pyruvate to lactate for energy.
- Failure of the Cori cycle leads to hypoglycemia
What is more common: hyper or hypoglycemia with sepsis? What is the prognosis of this?
Hyper, but hypo has a worse prognosis
What is the mechanism through which there is hyper or hypoglycemia with sepsis?
Not totally known, but suspected to be 2/2 cytokine release
What are the causes of fasting hypoglycemia?
- Islet cell tumor
- Liver failure
- Hypercatabolic state
- Prolonged EtOH consumption
What are the etiologies that can produce postprandial hypoglycemia?
- Gastric resection
- Islet cell tumor
- Glycogen storage disease
- Heriditary fructose intolerance
What is hereditary fructose intolerance?
Insufficient liver aldolase B
What is type I GSD?
Van Gierke’s disease
-Deficiency in glucose-6-phosphatase leads to the inability to export new glucose
What is type II GSD?
Pompe’s disease
-Defect in acid maltase (alpha glucosidase), which is required for the degradation of glycogen. –presents with cardiac hypertrophy
What is type III GSD?
Cori’s disease
-Defect in the glycogen debranching enzyme, leading to large glycogen granules
What is type V GSD?
Defect in muscle glycogen phosphorylase, which renders the muscles unable to utilize stored glycogen.
This presents as muscle cramps with a lack of lactic acid
What is the treatment for postprandial hypoglycemia 2/2 gastric resection? Why does this occur?
Smaller meals more frequently
Gastric bypass leads to a hyperplasia of beta cells d/t compensation for lower calorie intake
What abx can cause hypoglycemia?
Fluoroquinolones
What NSAID can cause hypoglycemia?
Indomethacin
What antimalarial drug can cause hypoglycemia?
Quinine
What is Whipple’s triad?
- Hypoglycemia
- ssx of hypoglycemia
- relief of ssx after restoration of normoglycemia
How do you diagnose an Islet cell tumor?
FBG less than 40 mg/dL with an elevated insulin level
How do you distinguish between an insulinoma and artifactual hypoglycemia?
Used a collection tube that contains an inhibitor of glycolysis
What happens to ketogenesis with exogenous insulin administration?
Suppressed
What is the ketone that should be measured with ketosis?
Beta-hydroxybutyrate
How do you differentiate between insulinomas and sulfonylurea use?
Check levels of oral hypoglycemic agents
What are the glucose, insulin, c-peptide, beta-hydroxybutyrate levels with autoimmune dz against insulin? How do you confirm?
Low glucose
High insulin
High c-peptide
Low ketones
Check abs
What is the purpose of the 72 hour fast with hypoglycemia?
Checking for deficiency in glucose or too much insulin with fasting
What BG level is diagnostic for an insulinoma after a 72 hour fast?
Less than 50 mg/dL, with high insulin levels
What BG level is diagnostic for an insulinoma after a 72 hour fast and glucagon administration?
Rise above 50 for a while, but then sharply decline
What are the ketone levels with an insulinoma after a prolonged fast?
Low
How is tolbutamide used to diagnose and insulinoma?
(first gen sulfonylurea) It promotes insulin production, but BG should return to normal after 3 hours in normal patient. Will remain high if there is an insulinoma
How is glucagon used to diagnose an insulinoma?
BG will increase initially, but then sharply decrease with an insulinoma
What is the treatment for hypoglycemia?
- Oral sugar if conscious
- D5 or D10 IV + glucagon
What is the treatment for an insulinoma?
Surgical resection
What is the calcium stimulation test?
Injecting calcium will increase insulin secretion. This can help localize a tumor on imaging
