Endocrine

Question 1

When do you test for pituitary hormone levels in pituitary incidentaloma?

Answer 1

If < 1 cm - just prolactin

If > 1 cm in size
Also check - TSH, LH, FSH, IGF, 24 hr urine cortisol

Question 2

Kallman v. Klinefelter

Answer 2

Kallman - anosmia, dec FSH/LH

Klinefelter - high FSH/LH

Question 3

Tx of Acromegaly

Answer 3

Cabergoline (inc dopamine, dec GH release)

Octreotide (somatostatin inhibits GH release)

Pegvisomant (GH receptor antagonist)

Question 4

How do you interpret a normal T4 when suspect hypothyroidism?

Answer 4

If TSH very high (2x ULN) w/ normal T4 … replace thyroid hormone

If TSH (< 2x ULN) w/ normal T4 … check anti-thyroid peroxidase and anti-thyroglobulin antibodies … if positive then replace thyroid hormone

Question 5

How do you treat subacute thyroiditis?

Answer 5

aspirin

TENDER!

Question 6

Tx of Hypercalcemia

Answer 6

1 - hydration (NS) + diuretics if not peeing on own

2 - Bisphosphonates

3 - calcitonin (rapid onset)

Question 7

Indications for Removing Parathyroid Glands

Answer 7

1 - osteoporosis

2- age < 50 yo

3- renal involvement / stones

4- Ca consistently 1 above normal limit

Question 8

How does Ca affect EKG?

Answer 8

Hypocalcemia - prolonged QT

Hypercalcemia - shorter QT

Question 9

Tx of Adrenal Mets

Answer 9

Mitotane

Question 10

MEN Syndromes

Answer 10

1 - parathyroid, pancreatic tumors, anterior pituitary

2 - medullary thyroid, parathyroid, pheo

3 - medullary thyroid, pheo, GI neuromas (MARFAN LIKE)

Question 11

When should people w/ hirsutism get biochemical tests? Which tests?

Answer 11

If irregular periods and virilization (clitoromegaly)

tests = prolactin, DHEA, testosterone level, FSH/LH, 17-hydroxyprogesterone

Question 12

PCOS Diagnostic Criteria

Answer 12

2/3

1- Clinical hirsutism OR high testosterone/DHEA

2- Irregular menstruation

3- US showing 10 cysts w/ ovary > 10 cm

Question 13

PCOS Tx

Answer 13

• lifestyle mod + check glucose, lipids, BP, weight
• OCPs w/ progesterone
• metformin
• last resort is spironolactone if hirsutism does not go away

Question 14

How does estrogen affect thyroid function?

Answer 14

Inc estrogen (not topical) –> inc thyroid-binding globulin (less catabolism/ more synthesis in liver) –> normal thyroid person then makes more T4 to bind this new globulin (will then have elevated total T4 but normal free T4 on labs)

In someone who is hypothyroid, they will not be able to make more T4 and will need increased dose of SYNTHROID to compensate

Question 15

What decreased thyroid-binding globulin?

Answer 15

Androgens

Steroids

Slow release nicotinic acid

Question 16

Interactions w/ Levothyroxine

Answer 16

Dec absorption … if taken with iron supplement, calcium, cholestyramine, sucralfate, PPIs

Inc TBG = inc requirement
Dec TBG = dec requirement

Inc thyroid hormone metabolism … inc requirement … caused by rifampin, phenytoin and carbamazepine

Question 17

Euthyroid Sick Syndrome

Answer 17

Abnormal thyroid labs in the setting of serious acute illness

Most commonly normal TSH and T4 but low T3

Thought to be 2/2 decreased peripheral T4 –> T3 conversion