Thyroid

Question 1

What is T4?

Answer 1

Precursor to thyroid hormone - goes into organ of function to be converted into functioning of molecule

Question 2

What is T3?

Answer 2

Thyroid hormone (2 tyrosine linked + iodine)

Question 3

What are the results of the thyroid function tests if dx = hypothyroidism?***

Answer 3

T4: low, T3: normal or low, TSH: high, serum thyroglobulin: low

Question 4

What are the results of the thyroid function tests if dx = hyperthyroidism?***

Answer 4

T4: high, T3: high, TSH: low, serum thyroglobulin: high

Question 5

What is Hashimoto’s Thyroiditis?

Answer 5

Autoimmune disorder: antibodies against thyroid peroxidase and/or thyroglobulin destroy thyroid gland follicles

Question 6

Name clinical presentations of hypothyroidism:

Answer 6

• Slowing of body functions (bc thyroid hormones stimulate response of adrenergic system)
• Puffiness, droopy eyelids, coarse/thin hair
• Saddle nose, thickened lips

Question 7

Name sx of Hashimoto’s thyroiditis (HT):

Answer 7

• goiter
• slower metabolism
• weight gain
• fatigue
• depression
• bradycardia
• constipation
• muscle weakness
• memory loss
• infertility
• hair loss
• reaction hyperthyroidism

Question 8

What is HT often misdiagnosed as?

Answer 8

• depression
• anxiety
• bipolar

Question 9

How is HT detected?

Answer 9

• Presence of specific antibodies against thyroglobulin and thyroid peroxidase
• Increased TSH
• Lymphocyte invasion of thyroid gland
• detected via radioactive uptake scan (iodine), ultrasound*

Question 10

What is a precaution with thyroid hormone tx for hypothyroidism?

Answer 10

May increase adrenergic receptor sensitivity to catecholamines (normal levels of NE/E, but hyper response)

Question 11

What is the effect of hypo/hyperthyroidism in regards to pregnancy?

Answer 11

Hypo: difficulty becoming pregnant
Hyper: abortion common when pregnant

Question 12

What is used to tx hypothyroidism?

Answer 12

Iodine: if due to iodine deficiency (seen in elderly/poor)
T4: if due to gland failure (body converts T4 to T3 PRN)

Question 13

What is the most common form of hyperthyroidism?

Answer 13

Grave’s disease

Question 14

Grave’s disease pathopysiology:

Answer 14

Activates antibody to TSH receptor –> increased T3 and T4

Question 15

Name 3 dx parameters for hyperthyroidism:

Answer 15

1) < 40 y/o - nervous system effects seen
2) > 40 y/o - CV effects seen
3) catacholamine response

Question 16

What is the treatment of choice for hyperthyroidism:

Answer 16

radioiodine (131T)

Question 17

Radioiodine MOA:

Answer 17

Ionizing radiation destroys the gland

Question 18

What is a caution with radio iodine tx?

Answer 18

Other antithyroid drugs bc radioiodine must be concentrated into uptake gland (management: stop anti-thyroid drug 2 days before and after)

Question 19

Why are other antithyroid drugs a caution in tx with radio iodine?

Answer 19

Other antithyroid drugs bc radioiodine must be concentrated into uptake gland (management: stop anti-thyroid drug 2 days before and after)

Question 20

Radio iodine is CI in?

Answer 20

Pregnancy and children

Question 21

What are 4 precautions in radio iodine tx?

Answer 21

1) delay in response (2-6 months)
2) radiation-induced thyroiditis
3) hypothyroidism
4) thyroid cancer

Question 22

Thioamide drugs MOA:

Answer 22

blocks thyroid hormone synthesis (onset needs depletion of thyroid hormone stores)

Question 23

Thioamide drug therapy schedule:

Answer 23

therapy is adjusted and/or reduced every 4-6 weeks

Question 24

What are 2 advantages of PTU?

Answer 24

1) Fast decrease in T3 due to its peripheral effects
2) Preferred in pregnancy bc does not cross placenta extensively, no teratogenic reports, only 1/10 crosses into breast milk

Question 25

PTU SEs:

Answer 25

1) Rash, arthritis-like sx
2) Leukopenia (management: routine monitoring. stop tx at first sign of sore throat/fever)
3) Agranulocytosis (management: reversible when tx is stopped)

Question 26

Why is propranolol used as an adjunctive tx in hyperthyroidism?

Answer 26

To better CV sx/toxicity (may suppress conversation of T4 to T3)