Hypoglycemia/insulinoma

Question 1

Describe three things in Whipples Triad

Answer 1

– 1) symptoms/signs consistent with hypoglycemia

– 2) Low measured plasma glucose concentration

– 3) Resolution of symptoms/signs with increasing plasma glucose

Question 2

Define hypoglycemia

Answer 2

Plasma glucose low enough to cause signs or symptoms including impairment of brain function. Typically < 70 mg/dl and whipples triad

Question 3

What are some defenses against hypoglycemia?

Answer 3

release of glucagon by alpha cells to increase gluconeogenesis

decrease glucose clearance in kidney

decrease insulin

incrase ACh and NE

Question 4

response of following hormones during HYPOglycemia

insulin

glucagon

epi

cortisol growth hormone

Question 6

How does epinephrine increase glucose levels?

Answer 6

causes increase gluconeogeneis by liver

inhibits insulin release from beta cells

increase glycolysis from muscle and lipolysi from fat

Question 7

What are Neurogenic symptoms of Hypoglycemia

Answer 7

• Tremor • Palpitations • Anxiety/arousal • Sweating • Hunger

Question 8

Neuroglycopenic sypmptoms of Hypoglycemia

Answer 8

• Cognitive impairment • Behavioral Changes • Psychomotor abnormalities • Visual changes • Seizures • Coma

Question 9

What drugs can cause hypoglycemia?

Answer 9

insulinoma, nesidioblastosis, post gastric bypass

Question 10

defiicency of which hormone can cause hypoglycemia?

Answer 10

cortisol

Question 11

Critical illness such as _____ can cause hypoglycemia

Answer 11

liver/kidney/heart fail

sepsis

severe malnourishtmet

Question 12

• Insulin secreting tumors of pancreatic origin that cause hypoglycemia

Answer 12

Insulinoma

Question 14

• Occurs in 1‐4 people per million
• 1‐2% of all pancreatic neoplasms
• 90%: benign, solitary, intrapancreatic, < 2 cm

Answer 14

insulinoma

Question 15

Where in the pancrease are insulinomas located?

Answer 15

Evenly distributed throughout the pancreas

Question 16

When workig up a pt for insulinoma when do we get imaging?

Answer 16

Diagnosis made per hormonal studies when hypoglycemic. Imaging helps to localize an insulinoma after the diagnosis is made.

Question 17

What is the gold standard test to dx insulinoma?

Answer 17

Supervised fast

• Provoke hormonal responses that maintain euglycemia
• Normally symptomatic hypoglycemia should not occur after a prolonged fast given gluconeogenesis

Question 19

What are the parameters necesseary to dx Insulinoma in a supervised fast?

Answer 19

• End Points for the test

glucose ≤ 45 mg/dl

– Signs/symptoms of hypoglycemia

Glucose ≤ 55 mg/dl + Whipple’s triad

Question 20

Both proinsulin and C‐peptide are secreted with_____ insulin (including sulfonylureas) Neither Proinsulin or C‐peptide is contained within_____ pharmacologic insulin

Answer 20

endogenous

exogenous

Question 21

what is the cutoff plasma glucose for insulinoma and regular people during fasting

Answer 21

55

you should be able to maintain euglycemia for up to 72 hours

Question 22

YOu perform fasting test on pt. they have below normal glucose and INcreased insulin, what does this indicate?

Answer 22

isulin above 3 micro = insulinomas/ exogenous insulin/ sylfonlurease or autoimmune

**need to get C peptide!

Question 23

Why do we order a C-peptide on pts with hypoglycemia and elevated insulin during a fasting test?

Answer 23

to tell if the insulin is endogeous (high C-peptide)= insluinoma or sulfynrueas

or exogenous (low C peptide)

Question 24

Why do you need to ourder a sulfonulurea screen in pt with suspect insulinoma?

Answer 24

because both as the same lab values of hypoglycemia, incresaed insluin and increased C peptide

Question 25

What do the B-hydroxybutyrate levels look lik in pt with insulinomas?

Answer 25

The are low but they shuld be HIGH in fasted states

Question 26

When do we use the mixed meal test?

Answer 26

• Not standardized and validated like the 72 hour fast.
• Used to evaluate patients with postprandial symptoms following for example GI procedures such as Roux en Y gastric bypass surgery.