Endocrinology 2

Question 1

If high Sex hormone globulin - what is reduced?

Answer 1

Insulin
Androgen
FSH/LH

Question 2

PCOS ultrasound findings?

Answer 2

12 follicles +/- string of pearls

1 ovary > 10 mls

Question 3

Sex hormone globulin binding affinity?

Answer 3

Dihydrotestosterone the most!
Testosterone - 2nd
Estradiol - 3rd

Question 4

COCP does what?

Answer 4

Increase SHBG - bind to estradiol ( ovaries androgen)

Question 5

What can be given to induce ovulation?

Answer 5

Letrozole (1st line)

Clomiphene (2nd line)

Question 6

Hypothalamic amenorrhoea (Tertiary) causes?

Answer 6

Intense exercise - Female athlete triad
—–Amenorrhea + Reduced bone density due to eating disorder

Reduce weight/calorie intake = reduced leptin

High stress - Cortisol inhibit GnRH

Question 7

Biotin cause false Hyperthyroidism (Graves presentation) why?

Answer 7

Biotin bind to Streptavidin site = thyrotrophin (TSH) can’t bind and signal it = so low TSH (falsely low)

No signal so all Free T4 roams around = so high T4 (falsely high)

Question 8

How clexane affects Thyroid hormone long term?

Answer 8

Displace T3/4 from binding proteins = low T3/4

Question 9

How does anticonvulsants affect thyroid hormone?

Answer 9

Hypothyroidism - induce high thyroid hormone metabolism

Question 10

How does lithium affect thyroid hormone?

Answer 10

Lithium reduces pinocytosis process - so thyroid hormone stays in colloid = goitre

Question 11

When do thyroidectomy?

Answer 11

Large goitre + obstruction
Active Graves’ opthalmopathy

Co-existing Hyper parathyroidism
Thyroid malignancy

Question 12

When do RAI?

Answer 12

Relapse post anti-thyroid medications
Poor surgical candidate
Doesn’t want children / breast-feeding

Question 13

what happens in sick euthyroidism?

Answer 13

Low T3 syndrome
-Rapid inhibition of D1 - drops T3

T4/TSH normal but if goes on - T4/TSH drops as well

Question 14

Causes of secondary hyperthyroidism?

Answer 14

Assay interference - main cause

IF assay interference ruled out;
TSHoma/ Thyroid hormone resistance

Question 15

Medications to prevent DM retinopathy?

Answer 15

Anti-VEGF therapy

Fenofibrate

Question 16

If atherosclerotic event + obese is dominant in DM patients - use what?

If HF + CKD is dominant in DM patients - use what?

Answer 16

GLP-1 receptor agonist

SGLT2 inhibitors

Question 17

GnRH antagonist - Degarelix benefit?

Answer 17

Avoid testosterone surge thus flare

Question 18

Androgen receptor blocker mechanism of action?

Answer 18

Block 17a hydroxylase enzyme

Question 19

Castration of testosterone - aim testosterone level?

Answer 19

< 1.7 nmol

Question 20

Main hormone secreted by anterior pituitary hormone?

Answer 20

Growth hormone

Question 21

Iron polymatose infusion causes?

Answer 21

Reduced serum PO4 - increase FGF-23

Question 22

How leptin induces satiety?

Answer 22

Stimulate POMC neurons

Inhibit Neuropeptide Y neurons

Question 23

What causes metabolic syndrome?

Answer 23

TNFa from Adipocyte

Question 24

Orlistat mechanism of action?

Answer 24

Lipase inhibitor - reduce fatty acid absorption

Question 25

Acromegaly has what type of cancer?

Answer 25

Thyroid cancer

Question 26

Diuretics in nephrogenic DI?

Answer 26

Paradoxical effect - diuresis causes hypovolemia | Then body reabsorb NA at PCT so less loss of NA/H20 in DCT

Question 27

Extra-adrenal tumor of pheochromocytoma - name? and cause?

Answer 27

SDH8 mutations = Paragangliomas ( sympathetic system)

Question 28

PCOS infertility pathway?

Answer 28

1. High adipocytes - high estrogen - inhibit FSH 2. High insulin - high 17a hydroxylase - more androgen 3. High LH

Question 29

How clomiphene helps fertility?

Answer 29

Induce ovulation - GnRH agonist - increases LH + FSH

Question 30

Testosterone supplement only for what type of hypogonadism?

Answer 30

Secondary ( pituitary/hypothalamus) hypoGnRH hypogonadism