Hypoglycemia and Islet Tumors

Question 1

definition of hypoglycemia

Answer 1

whipple’s triad: symptoms, low sugar <40 - low enough to cause neuroglycopenia

Question 2

explain the difference b/t children and adult glucose homeostasis

Answer 2

in children, liver is running at max gluconeogenesis rate during fasting –> children are more sensitive to changes is metabolism
in adults, liver isn’t putting out the full potential of glucose

Question 3

disorders that cause neonatal and childhood hypoglycemia

Answer 3

genetic disorders in glycogenolysis, FA metabolism, AA metabolism
transient hyperinsulinemia (post-birth from woman w/ poorly controlled DM)
medication related - insulin or ethanol
hormone deficiency: GH, cortisol

Question 4

what causes persistent hyperinsulinemic hypoglycemia of infancy?

Answer 4

1. gain of function mutation of islet cell glucokinase
2. gain of function mutation of mitochondrial glutamate dehydrogenase –> leucine is an activator
3. loss of function mutation of beta cell ATP dependent potassium channel

Question 5

causes of post-meal hypoglycemia in children

Answer 5

hyperinsulinism-hyperammonia syndrome (protein ingestion)

after abdominal surgery

Question 6

causes of post-meal hypoglycemia in adults

Answer 6

after abdominal surgery
NIPH: non-insulinoma pancreatogenous hypoglycemia syndrome
insulinomas

Question 7

“reactive hypoglycemia”

Answer 7

not a disease - brought on by ingesting lots of carbs

if necessary - acarbose tx - to slow starch absorption)i

Question 8

are islet cell tumors usually functioning?

Answer 8

no - 60% non-functioning

Question 9

insulinoma - rule of 10

Answer 9

10% malignant
10% multifocal
10% diffuse