Cohen Thyroid Physio/Patho

Question 1

For hyper-thyroid treatment; do you choose Methimazole or PTU?

Answer 1

Methimazole

less side effects, longer half life

Question 2

Why does exogenous thyroid hormone result in an atrophied thyroid gland and LOW Radioiodine uptake?

Answer 2

Because TSH gets shut off, which is responsible for up-regulating the Na/I symporter as well as Pendrin

Question 3

From the blood, sodium and Iodine enter follicular thyroid cells via Na/Iodide symporter. From follicular cells, the body uses ______ to bring Iodine into the colloid.

Answer 3

Pendrin

Question 4

Thyroid Receptor _____ is linked to the liver, hypothalamus, and pituitary

Answer 4

Beta

Question 5

Exogenous Thyroid hormone makes the thyroid feel ______

Answer 5

Tiny

Question 6

Key difference between TSH-Secreting Pituitary Adenoma and a Toxic Thyroid Nodule? (2 answers)

Answer 6

• Low TSH in Toxic thyroid nodule (because it’s Primary)

- High or “inapp. norm) in TSH adenoma (because it’s secondary)

Question 7

In pregnancy, hCG activates TSH also and Estrogen increases TBG. In early pregnancy what happens to total t4? Free t4? TSH?

Answer 7

• Total T4 goes up
• Free T4 slightly goes up because counter balanced with extra TBG
• TSH goes down, because the free T4 negatively feeds back and wins out

Question 8

Of all the causes of hyperthyroidism, what is the only one where you see LOW THYROGLOBULIN?

Answer 8

Exogenous Thyroid Hormone

Question 9

Formation of T4 and T3 are catalyzed by the enzyme _____, afterwards thyroglobulin gets endocytosed & combo’d w/ a lysosome to cleave & diffuse

Answer 9

Thyroperoxidase (TPO)

[Not Thrombopoietin]

Question 10

If a patient has hypothyroidism because of improper de-iodinase activity, then you provide which medication which has a short half-life and high risk of over-treatment?

Answer 10

Liothyronine (T3)

Question 11

In regards to thyroid function, what is Jod-Basedow Effect?

Answer 11

Mega Turn-on from excess iodine (hyper)

Question 12

Since hCG is similar to TSH, what happens in pregnancy?

Answer 12

You would expect increase of activity

Question 13

Diastolic HTN, Increased LDL & Triglyc is associated with ____Thyroidism

Answer 13

HYPO

Question 14

What would the THYROGLOBULIN levels be in a patient with destructive thyroiditis versus in excessive intake of thyroid hormone?

Answer 14

• High in destructive

- Low in Excess intake

Question 15

How do you distinguish destructive thyroiditis vs excessive intake of thyroid hormone?

Answer 15

Check Thyroglobulin levels

Question 16

TSH serum levels are not a good test in _____ hypothyroidism

Answer 16

Central

Question 17

The most common cause of primary Hypothyroidism in US is _____

Answer 17

Hashimoto’s (autoimmune); AKA Chronic Lymphocytic Thyroiditis
[Look for buttload of lymphocytes around follicles]

Question 18

To treat hypothyroidism, normally you provide _____, which has a long half-life and a lower risk of overtreatment

Answer 18

Levothyroxine (T4)

Question 19

In regards to thyroid function what is Wolff-Chaikoff Effect?

Answer 19

Auto Thyroid Shut-Off from too much Iodide (hypo)

Question 20

Thyroid Receptor _____ is linked to the Heart, GI, and Bone

Answer 20

Alpha

Question 21

T4 vs T3 Function

Answer 21

• T4: Reservoir

- T3: Active Form

Question 22

What is the negative feedback for TSH?

Answer 22

T4 levels

Question 23

Graves disease pathophys?

Answer 23

TSH antibodies activate thyroid

Question 24

Systolic HTN, decreased LDL & Triglyc is associated with ____Thyroidism

Answer 24

HYPER

Question 25

Methimazole (MMI) or Propythiouracil (PTU) will do what in regards to thyroid function?

Answer 25

Blocks production of T4/T3 by inhibiting TPO

Question 26

2 Key causes of transient thyroiditis WITHOUT hyperthyroidism

Answer 26

1. Transient Thyroiditis

2. Exogenous Thyroid Hormone

Question 27

On Embryonic Day _____, a bilobed early thyroid forms lateral to the trachea

Answer 27

50

Question 28

Hashimoto’s is autoimmune targeting _____

Answer 28

Thyroid gland

Question 29

Thyroid Parafollicular cells AKA C-Cells produce ______

Answer 29

Calcitonin

Question 30

Hormone levels expected in Graves?

Answer 30

Low TSH, High T4/T3

Question 31

TSH is the perfect screening test for primary thyroid disease, but not if there is pituitary or hypothalamic problem. Why?

Answer 31

TSH may be in a “normal” range, yet you would want it to be higher to compensate for a loss.

Question 32

What is best test for primary thyroid dysfunciton?

Answer 32

TSH levels

Question 33

Acutely, if the thyroid gland gets destroyed what happens to T3/T4? What about thyroglobulin levels?

Answer 33

Everything will raise up acutely

Question 34

List the three phases of the “Tri-phasic” Transient Thyroiditis often associated with viral illness or childbirth. Note that you should just provide supportive care, don’t provide meds usually.

Answer 34

1. Burst of T4/T3 from destroyed gland release into blood
2. TSH suppresion dunks everything low
3. Successful recovery

Question 35

Even though an adenoma and Graves will fully light up the thryoid in a radioactive scan, Describe the TSH levels in a TSH-producing adenoma vs Graves (2 answers)

Answer 35

• TSH would be high/(innappropriate norm) in adenoma

- TSH would be low in graves

Question 36

Is active thyroid hormone free or bound?

Answer 36

Free