Endocrine

Question 1

TSH regulation?

Answer 1

• feedback of free T3

+ control of TRH

Question 2

TSH screen used for?

Answer 2

Best initial test for thyroid fxn:

Low TSH = hyperfxn or over-treatment

High TSH = hypofxn or under-treatment

Question 3

Total T4 tells us?

Free T4 tells us?

Answer 3

All serum thyroxine (not good marker of fxn)

Direct measure of hormone activity

Question 4

Thyroglobulin (Tg) is?

Answer 4

Thyroid-exclusive protein used for T3/4 synth

Question 5

Tg levels tell us?

Answer 5

Normally low/undetectable

Used as marker for thyroid CA tx/recurrence

Question 6

Autoimmune Thyroiditis labs tests show?

Answer 6

Antibodies against:
Tg (TgAb)
Thyroid peroxidase (TPOAb)
TSH receptors (TrAb)
Thyroid-stim immunoglobulins (TSIg)

Question 7

TgAb (U) seen w/?

Evaluates?

Answer 7

(U) Hashimoto’s
(P) Grave’s

Likelihood of Grave’s to become hypothyroid

Question 8

TPOAb do what?

Seen w/?

Answer 8

Ø peroxidase that coverts T4 to T3

(U) Hashimoto’s
(P) Grave’s

Question 9

TrAb (TBAb) do what?

Seen w/?

Answer 9

Block TSH binding to receptors -> hypothyroid

ONLY Hashimoto’s

Question 10

TSIg seen w/?

Answer 10

(U) Grave’s

Question 11

Thyroid labs?

Answer 11

TSH:
High -> eval FT4 and all Ab’s
Low -> eval FT4/3, Tg, TPOAb, TgAb, TSIg

Question 12

Thyroid US used when?

Answer 12

Distinguish b/w solid or cystic nodules
Abn thyroid fxn tests
Palp thyroid
Eval tx of Grave’s

Question 13

Hyper/Hypo/Isoechoic is?

Answer 13

measure of density in US

Question 14

Hemorrhage w/i nodule seen as what ∆ on US

Answer 14

hyperechoic becomes hypo

Question 15

Heterogenous thyroid on US indicates?

Next step?

Answer 15

(P) autoimm destruction

Get TFTs, repeat US in 6 mo

Question 16

Nodules on US:

< 4mm, next step?

> 4 mm, next step?

Answer 16

< 4: repeat US 3mo

> 4: biopsy

Question 17

Test of choice for thyroid nodules?

Answer 17

fine needle aspiration (bx)

Question 18

Follicular cells considered what?

Answer 18

malignant until proven otherwise

Question 19

Thyroid nuclear scan used for?

Answer 19

Differentiate hot/cold:
Grave's
toxic goiter
thyroiditis
malignancy

Question 20

Nuclear scan results:

Hot?

Patchy hot?

Cold?

Answer 20

Hot = Grave’s

Patchy hot = Hashimoto

Cold = 20% CA

Question 21

Calcitonin is?

Does?

Answer 21

Thyroid gland hormone for Ca2+/PO4 metabolism

↓ blood Ca2+ via:
Osteoclast inhib (↓ bone resorp)
Renal tubular reabsorp inhib of Ca2+/PO4 (excreted in urine)

Question 22

PTH regulates?

Calcitriol (active Vit D) regulates?

Answer 22

minute-to-minute ionized Ca2+

intestinal Ca2+ absorption

Question 23

PTH circulates in what forms?

Answer 23

90% fragmented
10% intact

INTACT evals PT disease

Question 24

PT disease labs?

Answer 24

Intact PTH
Serum Ca2+
Ionized Ca2+
Mg
PO4
Vit D
BMD

Question 25

Test for BMD?

Tells us?

Answer 25

DEXA

bone mineral content (BMC)
bone area (BA)

BMC/BA = BMD

Question 26

T-score results from DEXA:

Normal?

Osteopenia?

Osteoporosis?

Severe?

Answer 26

N ≥ -1.0

Penia: between -2.5 and -1.0

Porosis: < -2.5

Sever: < -2.5 w/ fragility fractures

Question 27

Risks of fracture independent of BMD?

Answer 27

Age
Glucocort use
Low body weight
FHx
Smoke/drink

Question 28

Cortisol levels highest?

Answer 28

a.m.

Question 29

Meds that ↑ cortisol?

Answer 29

E2/birth control, amphetamines, spironolactone, prednisone

Question 30

Meds that ↓ cortisol?

Answer 30

androgens, lithium, levodopa

Question 31

Adrenal fxn labs?

Answer 31

Plasma cortisol
Plasma ACTH and Ab
24 hr urine cortisol
Cosyntropin stim test
Dexamethasone suppression test
Clonidine suppression test

Question 32

Plasma ACTH and Ab tells us?

Answer 32

anterior pitu fxn

Levels N higher in a.m.

Question 33

Plasma ACTH ↑ by what states?

Answer 33

stress, menses, pregnancy

Question 34

Meds that ↑ ACTH?

Answer 34

E2, ampheta, sprionol, insulin, ETOH

Question 35

Meds that ↓ ACTH?

Answer 35

steroids

Question 36

24 hr urine cortisol(17-OCHS) tells us?

Answer 36

HYPERadrenal fxn

Question 37

Meds that ↑ 17-OCHS?

Answer 37

spirono, quini’s, EMC

Question 38

Meds that ↓ 17-OCHS?

Answer 38

E2/birth cont

Question 39

Cosyntropin Stim Test tells us?

Answer 39

HYPOadrenal fxn

adrenal gland response to ACTH

Question 40

Rapid Cosyntropin results that confirm HYPOadrenal fxn?

Answer 40

Cortisol does NOT ↑ > 18 mg and > 7 above baseline

Question 41

Dexamethasone Suppression Test tells us?

What things interfere w/ results?

Answer 41

Hypothalm, pitu, adrenal fxn

Stress, E2, spirono, TCN, steroids can interfere

Question 42

Dexamethasone Suppression Test results w/ Cushings?

Answer 42

(Bilateral Adrenal Hyperplasia)

Prolonged/High Dose:
50% ↓ in plasma and urine cortisol

Rapid/Low Dose:
no ∆

Question 43

Dexamethasone Suppression Test results showing no ∆ in cortisol tells us?

Answer 43

Adrenal adenoma/carcinoma

Ectopic ACTH-producing tumor

Question 44

Clonidine Suppression Test tells us?

Answer 44

pheochromocytoma

Question 45

Clonidine Suppression Test done where?

Answer 45

inpatient

Question 46

Clonidine Suppression Test results positive for pheochromocytoma?

Answer 46

Levels HIGHER than the following at 3 hrs:
Norepi 0.2 - 0.8
Epi 0.04 - 2

Question 47

Adrenal imaging?

Answer 47

CT - standard for abdom masses

MRI - more accurate

US - not helpful

Question 48

Pituitary fxn labs?

Answer 48

Prolactin
GH/IGF1
LH/FSH
ACTH
Vasopressin

Question 49

HyperProlactin can result in?

Answer 49

↓ GnRH/FSH -> hypogonadism, amenorr

Milk prdxn

Question 50

GH best evaluated by what labs?

Answer 50

IGF1 due to pulsatile release of GH

Question 51

Pituitary Adenoma MRI results?

Answer 51

Size not indicative of extent of disease
Must have comparison MRI to follow
Must do lab w/u regardless of MRI results