Hyperthyroidism

Question 1

Drug of choice in pregnancy?

Answer 1

propylthiouracil in first trimester –> then can switch to methimazole

Question 2

signs and symptoms

Answer 2

nervousness, anxiety, irritable, insomnia
heat intolerance, sweating, weight loss, tremor
muscle weakness, palpitations, tachycardia, periorbital edema, warm moist skin/oily skin

Question 3

what is thyrotoxicosis?

Answer 3

excess thyroid hormon production

Question 4

what is factitious hyperthyroidism?

Answer 4

abusive replacement of thyroid replacement agents, intention to lose weight

Question 5

Jodbase dow phenomenon?

Answer 5

ingestion of large amount of iodine

Question 6

lab rest results

Answer 6

low TSH
high fT3 and fT4

Question 7

Which lab tests should be avoided in pregnancy?

Answer 7

Thyroid scan (scintigraphy) and Radioactive Iodine Uptake (RAIU)

Question 8

how long should treatment with methimazole or PTU be continued for?

Answer 8

1-2 years

Question 9

what are the complications for untreated hyperthyroidism?

Answer 9

cardiac abnormalities, myopathy, osteoporosis

Question 10

Treatment for thyroid storm?

Answer 10

PTU
propranolol
KI (Lugol’s solution)
rehydration
rest, sedation
acetaminophen (but avoid ASA or NSAIDs)

Question 11

When is lugol’s solution used?

Answer 11

for thyroid storm and prior to a thyroidectomy

Question 12

T/F: lugol’s solution can stain.

Answer 12

True - it contains Iodine and Potassium iodide, can stain skin, clothes and surfaces. Can be hard to remove.

Question 13

Which drug inhibits the conversion of T4 –> T3 more?

Answer 13

PTU

Question 14

Side effects of methimazole?

Answer 14

nephrotoxicity
hepatotoxicity
risk of skin rash
agranulocytosis

Question 15

Which drug is the drug of choice in pregnancy?

Answer 15

PTU

Question 16

Which drug should be avoided in children?

Answer 16

PTU

Question 17

Which drug is the drug of choice for general population and children?

Answer 17

methimazole

Question 18

A patient is on warfarin and was prescribed methimazole. What would you counsel?

Answer 18

monitor INR regularly, as hyperthyroidism can alter the response to warfarin

Question 19

What is a major concern of PTU?

Answer 19

hepatotoxicity –> monitor AST/ALT, bilirubin

Question 20

Drug interactions with PTU?

Answer 20

warfarin
BB
digoxin
theophylline

Question 21

What is the most common cause of hyperT?

Answer 21

Grave’s Disease

Question 22

What is a risk factor for graves disease?

Answer 22

smoking

Question 23

Pathophysiology of Grave’s Disease

Answer 23

thyroid receptor stimulating immunoglobulins stimulate the TSH receptor on the thyroid gland

Question 24

complications of hyperthyroidism

Answer 24

1. graves ophthalmology (exophthalmos)
2. thyroid storm

Question 25

does iodine block thyroid hormone production

Answer 25

yes

Question 26

how do nsaids worsen thyrotoxicosis?

Answer 26

displaces thyroid hormones from globulins

Question 27

drugs that can cause hyperthyroidism?

Answer 27

levothyroxine/liothyronine lithium (rare) tyrosine kinase inhibitors amiodarone (can cause excess free iodine load) interferon-alpha

Question 28

if a patient needs surgery to remove thyroid gland, what step needs to be done first?

Answer 28

initiate medical therapy prior to surgery to create euthyroid state.

Question 29

AEs of radioactive iodine used to damage thyroid tissue?

Answer 29

n/v/d metallic taste, sore neck *can worsen graves' opthalmopathy

Question 30

Drug interactions with radioactive iodine?

Answer 30

-amiodarone, levothyroxine -anti-thyroid drugs can reduce the effects, so stop the drug 2-3 days prior to RAI -lithium: can prolong RAI

Question 31

MoA of methimazole?

Answer 31

inhibits the incorporation of iodine tyrosine residues.

Question 32

MoA of Prophylthiouracil?

Answer 32

same as methimazole, plus inhibits peripheral conversion of T4 to T3

Question 33

AEs of Methimazole and PTU?

Answer 33

-arthralgia, rash, nausea -> can improve in 4 weeks -rare: edema, bone marrow suppression, agranulocytosis, hepatic/autoimmune effects -higher risk of hepatotoxicity and agranulocytosis in first 3 months

Question 34

which drug must be AVOIDED in the 1st trimester of pregnancy?

Answer 34

methimazole

Question 35

Drug interactions with PTU?

Answer 35

clozapine - can cause agranulocytosis as well

Question 36

after therapy with radioactive iodine, how long should you wait before conceiving?

Answer 36

wait at least 6 months

Question 37

Women of childbearing age require a NEGATIVE Pregnancy test within ___ hours of receiving Radioactive Iodine?

Answer 37

48 hours

Question 38

how long should a patient be treated with thionamides?

Answer 38

can be life-long, treat until euthyroid for atleast 12-18 months

Question 39

how often to monitor patients blood work?

Answer 39

Every 4-6 weeks until Euthyroid, then every 2-3 months. If > 18 months of therapy, monitor Q 6 months.

Question 40

how long does it take for symptom improvement in hyperthyroidism?

Answer 40

2-3 weeks. peak may occur in 4-6 weeks.

Question 41

Why is methimazole preferred over PTU?

Answer 41

Faster onset, long lasting, less side effects (hepatotoxicity)

Question 42

How long prior to radioactive iodine should anti-thyroid drugs be discontinued?

Answer 42

2-3 days