Week 1: Hypoglycemia

Question 1

Normal serum glucose values. Hypoglycemic values.

Answer 1

-Fasting 70-100mg/dl

<50: further eval needed

Question 2

Definition of severe hypoglycemia

Answer 2

• an episode that the patient cannot self treat, so that external help is required regardless of blood sugar values, or seizures or loss of consciousness.
• 30 will cause seizures or loss of consciousness

Question 3

Source of glucose used in fasting conditions

Answer 3

• Glycogen stores peaks at about 6-8 hours
• At best we have about 24 hours of glycogen stores to feed us in fasting state. Gluconeogenesis starts around peak of glycogen
• After, gluconeogenesis: catabolism, serve up muscle first. -In starvation state, body eats muscle and also reduces muscle mass to reduce caloric intake needed to exist

Question 4

Symptoms of hypoglycemia

Answer 4

• at around 55mg/dL: sweating, anxiety, palpitations, hunger, tremor
• around 50: cognitive dysfunction
• below 50: lethargy, stupor, combativeness
• below 30: seizures and coma,d eat
• see these as higher points in men than women

Question 5

Counter-regulatory hormones (oppose insulin actions)

Answer 5

1. Glucagon
   -acts on liver, stimulates glucogenolysis, gluconeogenesis
   -fast response
2. Adrenaline (epinephrine)
   -acts via beta adrenergic receptors
   -decreases peripheral utilization of glucose
   -stimulates lipolysis, increasing FFA, for gluconeogenesis
3. Cortisol and growth hormone
   -20-30 mins later
   -decrease peripheral utilization of glucose and work to enhance glucose production from liver
   These responses occur around 70 mg/dL

Question 6

What triggers the country regulatory response to hypoglycemia?

Answer 6

• receptors in the CNS sense glucose levels
• hypoglycemia itself increases glucagon gene expression direction
• glucose sensors in the liver may also trigger release of catecholamine directly

Question 7

counter regulatory impairment with hypoglycemia in diabetics

Answer 7

• glucagon response becomes impaired within few years of developing Type 1 DM
• possibly due to exogenous insulin, down regulating response of glucagon. Patients rely on sympathetic response
• hypoglycemic unawareness: response to hypoglycemia is blunted and they no longer experience warning symptoms

Question 8

Causes of Hypoglycemia: Fasting hypoglycemia

Answer 8

1. Deficient glucose production
   - hepatic dysfunction:glycogen storage dz, liver dz, hepatoma
   - endocrine: addison’s dz (too lil cortisol), hypopituitarism, glucagon deficiency
   - substrate deficiency: starvation, chronic renal failure, ketotic hypoglycemia of infancy
2. Overutilization of glucose
   - hyperinsulinism: insulinoma, noninsulinoma pancreatogenous hypoglycemic syndrome, sepsis with endotoximia, insulin auto-antibodies, drug induced
   - appropriate insulin: extra pancreatic tumors, cachexia with fat depletion, systemic carnitine deficiency

Question 9

Causes of Hypoglycemia: Drug-induced

Answer 9

1. Exogenous insulin
2. Insulin secretagogues: sulfonylurea drugs
   - they induce beta cell to secrete more insulin
3. EtOH: inhibitory effect on release of glycogen stores. blood sugar gets low
4. Misc: propanolol, salicylates, pentamidine
   - these affect ability of liver to make glucagon
   - propanolol is an antagonist to glycogen

Question 10

Dx of hypoglycemia -whipple’s triad

Answer 10

1. hypoglycemic symptoms
2. low blood glucose
3. symptoms relieved by glucose administration
   There’s also 72 hour fast, but not done frequently.

Question 11

Management of hypoglycemia

Answer 11

1. insulinoma
   - intraoperative ultrasound or MRI to visualize
2. Diabetes
   - HbA1c aimed to be less than 7 (nl4-6)
   - risk factors: strenuous exercise out of proportion of norm, antecedent hypoglycemia, alcohol ingestion
   - patient education: symptoms, prevention, carry sugar tablets, glucagon injection, check glucose before driving, ID

Question 12

Treatment of hypoglycemia in diabetics

Answer 12

• acute: give source of easily absorbed sugar (liquid)
• 10-15 g of glucose is used, followed by assessment of symptoms and blood glucose check
• repeated up to 3x. If not responding, call ambulance.