Thyroid

Question 1

Symptoms of Hypothyroidism

Answer 1

Fatigue, cold sensitivity, constipation, dry skin, unexplained weight gain, elevated cholesterol, heavy/irregular menses, thin hair, slow HR, depression, impaired memory

Question 2

Treatment of Hypothyroidism

Answer 2

Synthroid/Levothyroxine (T4) is preferred

Cytomel/Liothyronine (T3)

Question 3

Contraindications for thyroid replacement

Answer 3

any condition that tachycardia is dangerous

Question 4

Why is T4 preferred for thyroid replacement?

Answer 4

Longer half life and less potential for cardiac toxicity

Question 5

Why is T3 not preferred for thyroid replacement?

Answer 5

short half life, usually taken in combination with T4

Question 6

What do you have to consider when prescribing T4?

Answer 6

if patient is taking bile acid sequestrants, iron and antacids, estrogen, beta-blockers, digoxin, warfarin

Question 7

What can decrease the absorption of T4?

Answer 7

bile acid sequestrants, antacids, iron

Question 8

What can decrease the body’s response to T4 replacement?

Answer 8

estrogen

Question 9

What does T4 affect the efficacy of?

Answer 9

beta blockers, digoxin, warfarin

Question 10

What symptoms would you have if your dose of T4 is too high?

Answer 10

hyperthyroid symptoms - weight loss, palpitations, increased appetite, menstrual irregularities

Question 11

What is monitored when prescribing T4? How often do you monitor it?

Answer 11

TSH, T4

Check TSH after 3 mo, adjust dose by 10-25 mcg increments at 8 week intervals until TSH is in normal range

Question 12

What is the goal of thyroid replacement therapy?

Answer 12

to maintain TSH within normal limits

Question 13

What can lead to “burn out” of the thyroid?

Answer 13

chronic lithium therapy so TSH should be screened, may need replacement therapy

Question 14

Symptoms of hyperthyroidism

Answer 14

Sudden weight loss, tachycardia, arrhythmia, palpitations, increased appetite, nervousness, anxiety, irritability, tremor, sweating, changes in menses, heat intolerance, frequent BMs, goiter, difficulty sleeping, skin thinning, fine, brittle hair

Question 15

Treatment for hyperthyroidism

Answer 15

1. Thioamides

2. Radioactive Iodine

Question 16

Thioamides MOA

Answer 16

block synthesis of thyroid hormone (inhibits thyroid peroxidase catalyzed reactions)

Question 17

Radioactive Iodine MOA

Answer 17

destroys thyroid gland via radiation

Question 18

Side effects of Thioamides

Answer 18

Common: rash, fever, joint pain
Rare: impaired immunity, hepatotoxicity, vasculitis

Question 19

Contraindications of Thioamides

Answer 19

1. pregnancy (crosses placental barrier)

2. severe thioamide reaction

Question 20

Side effects of radioactive iodine

Answer 20

inflammation of salivary glands, dry mouth, altered taste, dental caries/pain, small risk of cancer, patient requiring lifelong thyroid replacement

Question 21

Contraindications for radioactive iodine

Answer 21

1. Absolutely in Pregnancy!!!!!
   even avoid pregnancy 6 mo after treatment
   *will require lifelong thyroid replacement

Question 22

Examples of thioamides

Answer 22

Propylthiouracil (PTU), methimazole, carbimazole

Question 23

How long does it take for anti-thyroid medications to lower thyroid hormone levels?

Answer 23

3-4 weeks –> consider beta blockers for immediate relief of signs/symptoms

Question 24

How often is TSH monitored when prescribing thioamides?

Answer 24

Initially monthly, then every 1-3 months when symptoms are under control

Question 25

Can hyperthyroidism go into remission?

Answer 25

yes

Question 26

Diseases associated with hypothyroidism

Answer 26

Hashimoto’s thyroiditis, myxedema, cretinism

Question 27

Disease associated with hyperthyroidism

Answer 27

Grave’s Disease, Thyrotoxic storm

Question 28

Which body systems does thyroid hormone affect?

Answer 28

Metabolic, cardiovascular, skin and hair, GI, musculoskeletal, hematologic, reproductive