Hypoglycemia

Question 1

what are the following hormonal responses to hypoglycemia?
a. norepinephrine
b. glucagon
c. epinephrine

Answer 1

a. norepinephrine —> lipolysis, adrenal medulla epinephrine production
b. glucagon —> hepatic gluconeogenesis, ketogenesis
c. epinephrine —> glycogenolysis

Question 2

what are some sympathetic (NE/E) vs neuroglycopenic symptoms and signs of hypoglycemia?

Answer 2

sympathetic - anxiety, sweating, tremor, tachycardia, hypertension, palpitations, nausea

neuroglycopenic - blurred vision, headache, drowsiness, confusion, aggressive behavior, memory loss, coma, seizure

Question 3

what is the Whipple triad of hypoglycemia?

Answer 3

1. Symptomatic hypoglycemia.
2. Plasma glucose <55mg/dl
3. Reversal of symptoms after carbohydrate load

Question 4

why does hypoglycemic unawareness occur?

Answer 4

Brain adapts/acclimates to a lower level of glucose availability

Symptoms of hypoglycemia occur at lower thresholds of blood glucose

Question 5

What is the most common cause of hypoglycemia?

Answer 5

Treatment of diabetes mellitus - could be due to insulin overuse, non-adherence to dietary schedule, reaction with alcohol, etc.

Question 6

are most insulinomas genetically predisposed or sporadic?

Answer 6

Over 90% are benign and sporadic - Most common hormone secreting neuroendocrine/carcinoid tumors

10% familial MEN1 including pituitary adenomas and hyperparathyroidism due to mutation in chromosome 11 (menin tumor suppression gene)

Question 7

what are 7 serological tests that can be done to diagnose the cause of hypoglycemia during fasting?

Answer 7

1. glucose
2. insulin
3. C-peptide (remnant of insulin synthesis)
4. proinsulin
5. beta hydroxybutyrate (ketone)
6. sulfonylurea and meglitinide screen (drug screen)
7. anti-insulin/receptor antibodies

Question 8

functional/reactive hypoglycemia vs organic/fasting hypoglycemia

Answer 8

Fasting (organic) hypoglycemia often happens after the person goes without food for 8 hours or longer.

Reactive (functional) hypoglycemia usually happens about 2 to 4 hours after a meal.

Question 9

what is the procedure of choice to confirm an insulinoma?

Answer 9

CT angiogram

can also use EUS (endoscopic ultrasound of pancreas), calcium stimulation of insulin secretion (measure which hepatic vein has more insulin), MRI, etc

Question 10

if a patient is experiencing postprandial hypoglycemia but it has been determined that the pancreas is not responsible for the underlying cause, what other organ/system should be considered?

Answer 10

consider GI tract - patients with bariatric surgery (accelerated gastric emptying), imbalanced GI motility (acetylcholine > norepi activity in the gut), etc

Question 11

childhood ketotic hypoglycemia

Answer 11

term used for episodes of low blood sugar with elevated blood or urine ketones occurring in some children if they have not eaten over a long period of time or when ill. It almost always goes away when the children are a little older and almost never causes any permanent harm.

child becomes lethargic/hysterical/ill with low glucose because brain is slow to change from glucose to ketone oxidation