Graves' Disease/Hyperparathyroidism

Question 1

Graves’ Disease therapy options

Answer 1

Antithyroid drug
Radioactive iodine
Thyroidectomy

Question 2

Factors favoring an option for antithyroid drug

Answer 2

Mild disease
Increased surgical risk
Limited life expectancy
Moderate-severe GO
No surgeon access
Previous neck operation/irradiation

Question 3

CIs to ATD

Answer 3

Previous known allergic reaction

Question 4

Patient preference factors for ATD

Answer 4

High value on avoidance of lifelong LT4 therapy, exposure to radioactivity, and surgery

Low value on need for monitoring and possible relapse

Question 5

Thioamides use

Answer 5

For Graves’ disease and to get patients chemically euthyroid before RAI/thyroidectomy

Question 6

Will thioamides cure Graves’?

Answer 6

NO

Question 7

Methimazole (MMI)

Answer 7

~10 times as potent as PTU

Preferred thioamide

Question 8

MMI dosing

Answer 8

Depends on FT4:
1-1.5x ULN: 5-10mg QD
1.5-2x-ULN: 10-20mg/day QD or BID
2-3x-ULN: 30-40mg/day BID

Question 9

MMI ADEs

Answer 9

Agranulocytosis, aplastic anemia, exfoliative dermatitis, hepatitis, abdominal pain, dark urine, jaundice, acholic stools

Most common are fatigue and rash

Question 10

MMI baseline labs

Answer 10

CBC with diff

Question 11

MMI monitoring

Answer 11

Leukopenia, pruritic rash, arthalgia

Question 12

MMI treatment algorithm

Answer 12

1. Consider CBC and liver panel to establish baseline values
2. Start MMI and dose on FT4 level
3. Check FT4, T3 levels in 2-6 weeks
   4a. If patient isn’t euthyroid, continue therapy at the MD (30-50% reduction from initial dose)
   4b. If patient IS euthyroid, taper dose down by 30-50% over a few weeks and repeat thyroid panel in 4-6 weeks
   5a. If patient isn’t euthyroid after that, increase dose slightly by 5-10mg/day and repeat the thyroid panel in 4-6 weeks
   5b. If patient IS euthyroid, continue therapy for 12-18 months and monitor thyroid labs every 2-3 months
4. Consider stopping MMi if TSH and TRAb levels are normal after 12-18 months of therapy

Question 13

Propylthiouracil (PTU)

Answer 13

Drug of choice in thyroid storm and 1st trimester of pregnancy

Question 14

Factors favoring an option for radioactive drug

Answer 14

Increased surgical risk, planning pregnancy >6 months out, CIs to ATD use, no surgeon access, previous neck operation/irradiation

Question 15

CIs to radioactive drug

Answer 15

Pregnancy, lactation, suspected or known cancer, unable to meet safety guidelines, informed caution for pregnancy 4-6 months out

Question 16

Patient preference factors for radioactive drug

Answer 16

High value on definitive control and avoidance of surgery

Low value on rapid cure, development of GO, and need for lifelong LT4 replacement

Question 17

Radioactive iodine (Na 131I)

Answer 17

Used to render the patient hypothyroid

Question 18

Radioactive iodine counseling points

Answer 18

Avoid high-iodine foods before treatment
No contact with children for 5 days
No contact with pregnant women for 10 days
No more than 2 hours of contact at a time
Bathroom etiquette
Avoid bodily fluid contact for 4 days
Flush things with bodily fluid contact
Wash things separately

Question 19

Radioactive iodine side effects

Answer 19

Transient hyperthyroidism, release of orbital antigen, thyroid tenderness, salivary gland tenderness/enlargement, dysphagia

Question 20

Radioactive iodine CI

Answer 20

Pregnant/lactating

Question 21

When do you use propranolol?

Answer 21

For symptomatic patients

Question 22

Iodides

Answer 22

Potassium iodide (SSKI), Lugol’s solution

Question 23

When are iodides used?

Answer 23

Surgery-prep drug, adjunct to RAI treatment

Question 24

Iodides side effects

Answer 24

“Iodism”

Metallic taste, head cold, burning mouth/throat, sore teeth/gums, stomach upset, diarrhea

Hypersensitivity reactions, salivary gland swelling, gynecomastia

Question 25

RAI treatment timeline: at diagnosis

Answer 25

Propranolol for symptoms
MMI in severe disease 3-7 days before the RAI dose
Females of childbearing potential do a pregnancy test before

Question 26

RAI treatment timeline: after RAI dose

Answer 26

Start steroids (prednisone, 0.4-0.5 mg/kg/day) 1-3 days after RAI
Start MMI PRN 3-7 days after RAI dose, taper weeks after RAI dose and D/C
Taper steroids over 2 months and taper the propranolol if used

Question 27

Post-RAI monitoring

Answer 27

Lab work q4-6 weeks that includes FT4, total T3, and TSH

Question 28

Post-RAI treatment if successful

Answer 28

If successful, start IBW-based levothyroxine dosing

Question 29

If hyperthyroidism persists after 6 months…

Answer 29

…suggest retreatment with radioactive iodine

Question 30

Factors favoring thyroidectomy

Answer 30

Larger goiter, malignancy suspected, planning pregnancy <6 months out, moderate-severe GO, high TRAb levels

Question 31

Thyroidectomy CIs

Answer 31

Substantial comorbidity, pregnancy, lack of access to high-volume surgeon

Question 32

Patient preference factors for thyroidectomy

Answer 32

High value on prompt, definitive control and avoidance of exposure to radioactivity

Low value on surgical risk and need for lifelong LT4 replacement

Question 33

Thyroidectomy complications

Answer 33

Transient or permanent hypocalcemia, hyperthyroidism can persist, vocal cord abnormalities

Question 34

Thyroidectomy prep goal

Answer 34

Get patient euthyroid and stable before surgery

Question 35

Thyroidectomy prep

Answer 35

Start MMI 6-8 weeks before surgery
Start iodide 10-14 days before surgery
Start beta-blocker 7-10 days before surgery
Consider normalizing calcium and vitamin D

Question 36

What to do post-thyroidectomy

Answer 36

Obtain serum calcium, intact parathyroid hormone levels, wean beta-blocker, stop MMI, start levothyroxine

Question 37

Drugs known to affect thyroid levels

Answer 37

Lithium and amiodarone