Hypothyroidism

Question 1

In pregnant patients + hypothyroidism, how much should levothyroxine be increased by?

Answer 1

2 tablets per week

Question 2

how often should TSH levels be monitored?

Answer 2

normal adults: q 4-6 weeks until stable, then every 6-12 months

elderly/angina/CVD: q 3-6 weeks (more frequently)

Question 3

What is myxdema coma?

Answer 3

medical emergency- severe hypothyroidism.
symptoms: hypothermia, extreme hypothyroidism, delirium/coma

Question 4

What is the mortality rate of myxedma coma?

Answer 4

60-70%

Question 5

how to manage myxedema coma?

Answer 5

• IV corticosteroids before administering levothyroxine.
• IV levothyroxine loading dose, then maintenance dose. Switch to PO once stabl.
  -supportive tx for hypothermia, hypovolemia, hypoglycemia, hypoventilation

Question 6

Efficacy Endpoints?

Answer 6

TSH: 0.5-4.7
Free T4: 9-24
Free T3: 3.5-7.7

Question 7

Counselling points for Levothyroxine?

Answer 7

1. take 30 min before food
2. space by 4 hours from calcium, iron products
3. space by 6 hours from cholestyramine
4. if taking biotin, stop 48 hrs before lab test
5. do blood test first if switching between brands (Synthroid vs Eltroxin)

Question 8

When is liothyronine (T3) used?

Answer 8

in thyroid cancer after levothyroxine.

Question 9

Does liothyronine interact with Iron products?

Answer 9

no

Question 10

Primary hypothyroidism in relation to TSH levels?

Answer 10

elevated TSH

Question 11

Secondary hypothyroidism in relation to TSH levels?

Answer 11

low or normal TSH

Question 12

What are the side effects of Levothyroxine or Liothyronine?

Answer 12

Hyperthyroid symptoms, may worsen angina.

Question 13

Which drugs may reduce serum concentrations of T4 or T3?

Answer 13

estrogen
carbamazepine
phenytoin