Hypoglycemia

Question 1

Whipple’s triad

Answer 1

blood glucose<55 hypoglycemic symptoms relief with glucose administration

Question 2

C peptide levels are useful

Answer 2

C peptide is released after endogenous insulin is made (it’s the final step) so if C peptide levels are high it means that patient is making their own insulin and getting hypoglycemic. If C peptide levels are low it means that someone is using exogenous (iatrogenically) insulin.

Question 3

if patient has normal C peptide and Whipple’s triad for hypoglycemia, need to rule out

Answer 3

surreptitious sulfonylurea use. Get a hypoglycemic drug screen. Glyburide has a long duration of action and so it can be seen.

Question 4

insulinomas can cause

Answer 4

recurrent episodes of hypoglycemia and normal to high insulin and C peptide levels. Tumors are rare and seen in older age. If hypoglycemia screen is negative would get a abd CT scan to look for it

Question 5

when do we a 72 hr fast?

Answer 5

if people who DO NOT HAVE CONFIRMED hypoglycemia. The prolonged fasting of 72 hours can induce hypoglycemia and facilitate further investigation. Then after the fast, a glucagon is given. with prolonged fasting, the hepatic glycogen stores are depleted and administration of glucagon normally causes a small rise in blood glucose >25 mg/dl which suggests that hepatic glucogen has been maintained due to inappropriate hyperinsulinemia. in normal pts plasma glucose does not respond to glucagon because 72 hr fast will have depleted the hepatic glycogen stores.

Question 6

intepretation of hypoglycemia testing

Answer 6

Question 7

mixed meal

Answer 7

food types that have induced onseto f symptoms in the past. SHould have hypoglycemic lab tests measured at baseline and then every 30 minutes for five hours after consuming a mixed meal.

Checking plasma glucose, insulin C peptide, B hydroxybuytrate (low in presence of insulin) and proinsulin.

Repeat these tests at the time of symptomatic hypogyclemia beforegetting carbohydrates.

If there’s sympotmatic hypoglycemia during mixed meal testing pt should be screened for insulin secretagogues (sulfonylurea and meglitinides) and insulin antibodies.

Question 8

causes of hypoglycemia without diabetes are:

Answer 8

drug or ETOH use, critical illness, hormonal deficiency, non islet cell tumor and endogenous hyperinsulinism and accidental or intetional hypoglycemia and prior Roux en Y surgery.

Question 9

72 hr fast is

Answer 9

prolonged fasting while measuring hypoglycemic labs (plasma glucose, insulin, C peptide, Beta hydroxybutyrate, and proinsulin) every 6 hrs followed by 1 to 2 hours once glucose is <60 or pt becomes symptomatic