Thyroid and Parathyroid

Question 1

T4 is converted to T3 primarily where?

Answer 1

Liver

Question 2

What is the best initial test to check thyroid function?

Answer 2

TSH levels

Question 3

TSH levels are tightly regulated by levels of what?

Answer 3

Serum levels of T4 and T3

Question 4

FT4 is more diagnostically relevant than TT4 and is used to evaluted what hormone?

Answer 4

TSH levels

Question 5

Thyroid peroxidase antibodies (TPO Ab) is most often found in?

Answer 5

Hypothyroidism (Hashimoto’s)

Question 6

Thyroglobin antibodies (TgAb) is most often found in?

Answer 6

Hypothyroidism (Hashimoto’s)

Question 7

Thyrotropin receptor antibody (TRAb) is most often found in?

Answer 7

Hyperthyroidism (Grave’s)

Question 8

What functional study is used to evaluted suppressed TSH?

Answer 8

Radioactive Iodine/thyroid uptake scan

Question 9

What imaging study is used to assess structure of the thyroid gland tissue and nodules?

Answer 9

US

Question 10

What is the single most accurate, reliable, cost effective test to DX thyroid CA?

Answer 10

Fine needle aspiration

Question 11

Endogenous hyperthyroidsm is due to what?

Answer 11

Overproduction of thyroid hormone

Question 12

What are the 4 most common causes of endogenous hyperthyroidism?

Answer 12

Graves’ disease, toxic multinodular goiter (MNG), toxic adenoma, thyroiditis

Question 13

What are the most common causes of exogenous (iatrogenic) hyperthyroidism? (2)

Answer 13

Over-replacement in hypothyroidism, suppressive therapy (intentional for thyroid cancer)

Question 14

What lab values would you expect to see with primary hyperthyroidism?

Answer 14

Low TSH, high FT4, high T3

Question 15

What is the most common cause of primary hyperthyroidism?

Answer 15

Grave’s disease

Question 16

What lab values would you expect to see with subclinical hyperthyroidism?

Answer 16

Low TSH, normal FT4, normal T3

Question 17

What lab values would you expect to see with T3 toxicosis?

Answer 17

Low TSH, normal FT4, high T3

Question 18

Opthalmopathy (exophthalmos, proptosis) is a common sign of what?

Answer 18

Graves’ disease

Question 19

Radioactive iodine uptake and scan is used to evaluate what?

Answer 19

Hyperthyroidism

Question 20

What uptake % is normal on radioactive iodine uptake and scan?

Answer 20

15% uptake after 6 hrs

Question 21

Diffuse high/ elevated uptake on radioactive iodine uptake and scan indicates what?

Answer 21

De novo synthesis of hormone

Question 22

Diffuse low/decreased uptake after a radioactive iodine and uptake sckin can indicate what? (2)

Answer 22

Inflammation/destruction of thyroid tissues (thyroiditis) or extrathyroidal source of thyroid hormone (factitious thyrotoxicosis)

Question 23

What will Graves’ show on a radioactive iodine and uptake scan?

Answer 23

Diffuse uptake

Question 24

What will a nodule or toxin MNG show on a radioactive iodine and uptake scan?

Answer 24

Irregular uptake

Question 25

What is indicated by a hyperfunctioning "hot" nodule? (2)

Answer 25

Increased irregular uptake, rarely malignant

Question 26

What is indicated by a hypofunctioning "cold" nodule? (2)

Answer 26

Decreased irregular uptake, more likely to be malignant

Question 27

If you identify a cold nodule on radioactive iodine scan, what additional test should you consider?

Answer 27

FNA

Question 28

What are the treatment options for Graves'? (4)

Answer 28

Beta blockers (sx control), antithyroid drugs (Methimazole, PTU), radioactive iodine ablation, surgery

Question 29

What is the most common cause of primary hypothyroidism?

Answer 29

Hashimoto's thyroiditis (autoimmune)

Question 30

What are the 2 different types of central hypothyroidism?

Answer 30

Pituitary (secondary) or hypothalamic (tertiary)

Question 31

What will TSH and FT4 levels show with central hypothyroidism?

Answer 31

Both low (T3 also low)

Question 32

If TSH and FT4 levels are low and you suspect central hypothyroidism, what should the next step be?

Answer 32

Pituitary MRI

Question 33

What is the treatment for iatrogenic hypothyroidism?

Answer 33

Radioactive Iodine

Question 34

What medications can cause iatrogenic hypothyroidism? (4)

Answer 34

Lithium, amiodarone, other iodine-containing drugs, contrast agents

Question 35

What labs would you expect to see w/ primary hypothyroidism?

Answer 35

High TSH, low FT4, normal or low T3

Question 36

What labs would you expect to see w/ subclinical hypothyroidism?

Answer 36

High TSH, normal FT4, normal T3

Question 37

In primary hypothyroidism, the serum TSH is increased in a reflex effort to stimulate what?

Answer 37

The failing gland (represented by low serum FT4)

Question 38

What are the most important considerations when treating hypothyroidism with levothyroxine replacement? (4)

Answer 38

Weight based, take on empty stomach, mindful of meds that interfere w absorption, goal = acheive euthyroid state and alleviate sxs

Question 39

Pt presents for a routine PE when you note a thyroid nodule. How do you proceed?

Answer 39

TSH and US first

Question 40

What % of nodules are benign vs cancerous?

Answer 40

95% benign, 5% cancerous

Question 41

Most cancerous thyroid nodules are what?

Answer 41

Papillary

Question 42

When evaluating a thyroid nodule, if TSH is N or elevated, what should be ordered next?

Answer 42

Check for TPO antibodies

Question 43

If low TSH and low FT4 what is the most likely cause of hypothyroidism?

Answer 43

Central (secondary or tertiary)