L10: Thyroid

Question 1

Normal TSH

Answer 1

.3-5.0

Question 2

What etiology causes both TSH and T3/T4 to increase

Answer 2

Primary/pituitary adenoma

Question 3

Best initial test for thyroid function

Answer 3

TSH

Question 4

Normal Free T4

Answer 4

.8-2.8

Question 5

Exogenous hyperthyroidism

Answer 5

Iatrogenic or factitious

Question 6

Iatrogenic hyperthyroidism

Answer 6

Suppressive therapy: Thyroid Cancer (intentional)

Over-replacement in hypothyroidism

Question 7

Factitious hyperthyroidism

Answer 7

Taking thyroid meds: someone else’s

Question 8

Most likely to get Grave’s

Answer 8

<40 year old women

Question 9

TPOab aka

Answer 9

microsomal antibody

Question 10

TgAB aka

Answer 10

colloid antibody

Question 11

Antibodies in hyperthyroidism

Answer 11

+TPOab (microsomal antibody)
+TgAb (colloid antibody)
+TSH Receptor antibody
→ More specific: Thyroid-Stimulating Immunoglobulin (TSI)

Question 12

An extreme goiter could cause

Answer 12

Retrosternal extension

Question 13

Where is T4 converted to T3

Answer 13

peripheral tissues: Liver*, thyroid, kidney, other organs

Question 14

Liver damage could cause

Answer 14

elevated T4

Question 15

reflection of metabolism of thyroid

Answer 15

Radioactive Iodine Uptake and Scan

Question 16

When to scan after the patient ingests radioactive iodine

Answer 16

6 and 24 hours

Question 17

A normal Radioactive Iodine Uptake

Answer 17

15-25%

Question 18

Elevated Radioactive Iodine Uptake

Answer 18

Graves=homogenous uptake

Nodules/TMG=irregular uptake, “Hot”

Question 19

Low Radioactive Iodine Uptake

Answer 19

Inflammation/destruction of gland

Extrathyroidal source of hormone (factitious)

Question 20

Hot vs cold nodules

Answer 20

Hot are functional, take up iodine
Cold are nonfunctional
Cold are ~more likely~ to be malignant, but overall, most nodules are benign

Question 21

Grave’s management

Answer 21

Beta Blocker
ASA→ prevent clot formation in A. Fib
Thionamides: added to beta blockers for more severe symptoms
\+/- Radioablation
\+/- Surgery

Question 22

Methimazole

Answer 22

Thionamide with daily dosing

Question 23

Propylthiouracil (PTU)

Answer 23

Thionamides preferred in pregnancy

Question 24

Fatigue, amenorrhea, depression, weight gain, +/- goiter

Answer 24

Hypothyroidism

Question 25

Most likely cause of hypothyroidism

Answer 25

Hashimoto’s

Question 26

Primary hypothyroidism

Answer 26

Hashimoto thyroiditis: Autoimmune

Ab: TPOab, +/- TRAB (inhibitory, not stimulatory), TgAB

Question 27

Central (secondary or tertiary) hypothyroidism

Answer 27

Less than 5% of causes
All hormones decreased: TSH, T4/T3
Get a Pituitary MRI

Question 28

Iatrogenic hypothyroidism

Answer 28

Radioactive Iodine treatment
Medications: Lithium, Amiodarone
Iodine-containing drugs, Contrast medium
Nodules

Question 29

Amiodarone

Answer 29

will super duper give you Iatrogenic hypothyroidism

Question 30

Lithium

Answer 30

could cause Iatrogenic hypothyroidism

Question 31

Definitive test to diagnose cancer

Answer 31

FNA

Question 32

First step in evaluating a nodule

Answer 32

TSH and Ultrasound

Question 33

Nodule+ High TSH

Answer 33

FNA

Question 34

Nodule+Low TSH

Answer 34

thyroid uptake and scan

Question 35

Cold nodule: FNA?

Answer 35

Yes

Question 36

Hot nodule: FNA?

Answer 36

NO, do not stick a needle in it, risk of thyroid storm

Diagnose it using T3/T4

Question 37

Hot nodule+Normal FT4 and T3

Answer 37

Subclinical hyperthyroidism

Question 38

Hot nodule+High FT4 and T3

Answer 38

Overt hyperthyroidism