Hyper and Hypo-Thyroidism Flashcards Preview

Endo/Repro Exam 1 > Hyper and Hypo-Thyroidism > Flashcards

Flashcards in Hyper and Hypo-Thyroidism Deck (38):
1

Three types of thyroid hormones?

Thyroxine (T4)
Triiodothryonine (T3)
Reverse Triiodothryonine (rT3)

2

What thyroid hormone is produced the most?

T4 (90%)

3

What is the more potent thyroid hormone?

T3 (10x more)

4

In tissue, what turns T4 to T3?

5-deiodinase

5

Where are T3/T4 synthesized?

In the colloid of follicular cells

6

On what molecule are T3/T4 synthesized?

A large tyrosine-rich glycoprotein called thyroglobulin

7

How is iodide transported into the follicular cells?

Na/I cotransporter

8

What turns I- into I2?

Thyroid peroxidase

9

How is I2 conjugated onto tyrosine of thyroglobulin?

By thyroid peroxidase forming MIT and DIT

10

Thyroid peroxidase also couples MIT and DIT what do they form?

MIT + DIT = T3
DIT + DIT =T4

11

Where is iodinated thyroglobulin stored?

In the colloid of the follicular cells

12

What occurs to T4?

It is activated to more potent T3 in target cells

13

Where does T3 bind?

To both an extracellular and an intracellular receptor

14

5 physiologic effects of thyroid hormone?

Growth
CNS development
Skeletal/Cardiac muscle
Central sympathetic nervous stimulation
Upregulates lipid, carbohydrate, oxidative metabolism, protein synthesis

15

What are the four thyroid replacement drugs?

Levothyroxine (drug of choice)
Liothyronine
Liotrix
Desiccated thyroid

16

What is Levothyroxine?

T4

17

What is Liotrix?

T3 + T4

18

What is Liothyronine?

T3

19

What is desiccated thyroid?

Porcine thyroid

20

What is a potential SE of desiccated thyroid?

Antibodies forming against the porcine

21

What are the drug overdose SE of thyroid replacement drugs?

High sympathetic tone

22

What test can Liothyronine used for?

TSH suppression test

23

What are the 5 classes of anti-thyroid drugs?

Radioactive iodides
Anion inhibitors
Beta blockers
Iodides
Thioamides

24

What are the radioactive iodides?

131 I

25

What are the anion inhibitors?

Perchlorate
Pertechnetate
Thiocyanate

26

What are the Thioamides?

Methimazole
Propylthiouracil

27

How do Thioamides work?

Inhibit synthesis but not release by inhibiting thyroid peroxidase

28

When to use Thioamides?

Grave's Disease in children
Propylthiouracil: 1st trimester
Methimazole: 2nd and 3rd trimester

29

How do anion inhibitors work?

Competitively inhibit iodine uptake by follicular cells

30

How do the Iodides work?

Inhibits thyroid hormone release

31

Two possible effects from giving iodides?

Jod-Basedow Effect
Wolff-Chaikoff Effect
(opposites of each other)

32

What occurs in the Jod-Basedow effect?

Severe hyperthyroidism when a TSH stimulated thyroid suddenly receives an increased in iodine (body didn't have any Iodine and TSH was high so kick stated thyroid gland)

33

What occurs in the Wolff-Chaikoff effect?

Temporary suppression of acute hyperthyroidism by increased iodine intake

34

What does 131 I do?

Burns out half of the thyroid; long term treatment of hyperthyroidism

35

What do you never treat hyperthyroidism with?

Only a beta blocker! (malpractice lawsuit)

36

What are the signs of thyroid storm?

Fever
Sympathetic nervous system storm
Confusion/delirium
NVD

37

Thyroid storm treatment?

IV beta blocker (propranolol)
IV Propylthiouracil
Iodides
Glucocorticoids (inhibit peripheral T4->T3)

38

What are two iodides given?

Lugol's solution
KI