Quiz 30: Thyroid basics and practical applications

Quiz Summary

0 of 16 questions completed

Questions:

You have already completed this quiz. You cannot start it again.

Quiz is loading…

You must sign in or sign up to take this quiz.

You must first complete the following:

Results

Quiz complete. Results are being recorded.

Results

0 of 16 questions answered correctly

Your Time:

You have reached 0 of 0 point(s), (0)

Average Score
Your Score

Your grade: F
Your grade: D
Your grade: D+
Your grade: C-
Your grade: C
Your grade: C+
Your grade: B-
Your grade: B
Your grade: B+
Your grade: A-
Your grade: A
Your grade: A+

Current
Review
Answered
Correct
Incorrect

Question 1 of 16

1. Question
Basic thyroid concepts: There should be a better definition of the states of hypothyroidism (choose correct answer):
- Primary hypothyroidism – deficiency of output
- Thyroid dysfunction or functional hypothyroidism
- Decreased conversion of T4 to T3
- Increased conversion from T4 into rT3
- Thyroid resistance polymorphisms
- All of the above
- None of the above
Correct

Incorrect
Question 2 of 16

2. Question
Basic thyroid concepts (choose correct answer):
- Thyroxine (T4) is a prohormone that requires conversion to T3 to activate thyroid receptors
- Only 20% of the circulating Triiodothyronine (T3) is produced and released by the thyroid gland
- Peripheral “intracrine” conversion through the action of the deiodinase enzymes is the primary source of active thyroid hormone
- All of the above
- None of the above
Correct

Incorrect
Question 3 of 16

3. Question
Basic thyroid concepts (choose correct answer):
- Circulating levels of T4 and T3 may not fully assess the true activities of these hormones at the cellular level – therefore, clinical effects must be appreciated to both assess and adjust treatment of altered thyroid states
- Hypothyroidism, with the symptoms and physiological changes, can occur when T4 and TSH production or replacement is adequate, even high normal T4
- Clinical picture may be more important than lab testing
- All of the above
- None of the above
Correct

Incorrect
Question 4 of 16

4. Question
Basic thyroid concepts (choose incorrect answer):
- Control of conversion of T4 to T3 or rT3 is controlled peripherally by the selenodeiodinases D1, D2, and D3
- The changing patterns of activities of these enzymes are modified by aging, disease states, drugs, inflammatory cytokines and hormones (GH, DHEA, E2, P4)
- Selenium deficiency is uncommon in the United States
Correct

Incorrect
Question 5 of 16

5. Question
Thyroid Metabolism

Basic thyroid concepts (choose incorrect answer):
- Control of thyroid hormone activity within each cell is based on activation of the nuclear thyroid receptor (TR)
- TR is only bound by T3, not T4 – therefore, T4 is a prohormone
- TR is bound by both T3 and T4, making T4 a more prevalent though less tightly bound of the two thyroid hormones
- All tissues are exposed to the same plasma levels of T4 and T3
- Tissues control variable activity, TR-T3 binding, by rate of importation of T4, rate of conversion of T4 to T3 (D2), and rate of deactivation by D3
- There are 3 types of selenodeiodinase enzymes
- D1 found mainly in the liver, kidney, thyroid and pituitary and in circulating mononuclear cells, but conspicuously absent from the CNS
- Because of D1 absence from brain, mental symptoms such as fatigue can exist in the face of adequate circulating levels of T4 and T3
- D2 is found in most tissues and accounts for the majority (~60%) of T3 conversion
- D3 the deactivating enzyme – produces rT3
Correct

Incorrect
Question 6 of 16

6. Question
Factors that impair conversion of T4 to T3 and increase rT3 conversion – drugs (choose incorrect answer):
- PDE-5 inhibitors
- Glucocorticoids
- Amiodarone – several types of thyroid dysfunction seen with this drug
- Beta-adrenergic antagonists
- Propylthiouracil (PTU), Tapazole
- Synthetic progestins (BCPs, MPA)
- Elevated insulin or excessive treatment
- SSRIs, phenothiazines
Correct

Incorrect
Question 7 of 16

7. Question
Factors that impair conversion of T4 to T3 and increase rT3 conversion (choose incorrect answer):
- Aging
- Selenium deficiency
- Growth hormone deficiency
- Low DHEA/DHEAS
- High cortisol
- High E2 and SHBG
- Inflammatory cytokines – IL-1β, IFNγ and TNFα
- Zinc deficiency – copper excess
- Depression
- Diabetes mellitus
- Uremia
- Fasting
- Hepatic dysfunction
- Chronic infection, inflammation
- Cancer
- Stress (trauma, illness, post-op state)
- Blood transfusion
- Hemochromatosis
Correct

Incorrect
Question 8 of 16

8. Question
True or false: Euthyroid-Sick Syndrome is about conversion issues.
- True
- False
Correct

Incorrect
Question 9 of 16

9. Question
True or false: T3 conversion lessens in high cortisol/stress states.
- True
- False
Correct

Incorrect
Question 10 of 16

10. Question
True or false: T3 and TSH in stress states: T3 conversion is suppressed.
- True
- False
Correct

Incorrect
Question 11 of 16

11. Question
True or false: T3 and IL-6 in stress states: T3 conversion is suppressed.
- True
- False
Correct

Incorrect
Question 12 of 16

12. Question
True or false: Aerobic metabolism increases in hypothyroidism.
- True
- False
Correct

Incorrect
Question 13 of 16

13. Question
Thyroid metabolism: Key concepts (choose incorrect answer):
- Most thyroid dysfunction comes from a downward shift from T4 conversion to T3 primarily from reduced D2 activity
- Concurrently, there is increased relative production of rT3 primarily from T4 directly through increased D3 activities
- Treatment should be aimed at understanding the pathology, correcting the hormone/cytokine milieu, and improving the T3 to rT3 ratio
- The most direct method is the use of sub-suppressive low dose T3 alone
- Natural desiccated thyroid has a robust amount of T3 in it, but because of the T4 it also contains, it should not be used as a sub-suppressive low dose T3
Correct

Incorrect
Question 14 of 16

14. Question
Euthyroid dysfunction – Rx (choose incorrect answer):
- Small doses of T3 will reduce T4 and rT3 levels and suppressing TSH
- Start with 3 mcg SR caps AM and HS daily
- Increase weekly as long as there is no improvement in symptoms
- Doses above 12 mcg BID may be suppressive to TSH
- These doses should be reduced/stopped after 3–4 months of iodine and selenium
- In all cases when final T3 dosage is determined, add in at a minimum 50 mcg of T4
Correct

Incorrect
Question 15 of 16

15. Question
When thyroid replacement is required due to deficiency (choose incorrect answer):
- T4 plus T3 should be given together, in the morning, on an empty stomach
- T4 plus T3 should duplicate biologic patterns (T4 given hs – T3 up on awakening)
- T4 and Cytomel 5 mcg may be used
- Give T4 hs; T3 SR caps 3–5 mcg or Cytomel in the AM
- Monitor free T3 and TSH
- Goal to get free T3 to 3.0 – 4.0 ng/ml range with TSH 0.5–2.0 range
Correct

Incorrect
Question 16 of 16

16. Question
Changing from T4 replacement alone (choose incorrect answer):
- If changing from T4 alone, first measure free T3 levels and TSH and check levels monthly until stable
- Only about 10% of people can take T4 alone and convert successfully to T3 to meet their needs
- Change doses only if there are symptoms and freeT3 levels below 3.0 ng/ml
- Those patients that are aging or not well often need the addition of T3 to their treatment
- Reduce T4 as T3 doses are increased
- Keep TSH levels 0.5–2.0 range
- Target levels are best in the T3:T4 ratios – 1:10 up to 1:5
- T4 and T3 can be combined into a single SR capsule in the AM or split dosed AM and HS
Correct

Incorrect

Andropause Mastery

Quiz Summary

Information

Results

Results

Categories

Your grade: F

Your grade: D

Your grade: D+

Your grade: C-

Your grade: C

Your grade: C+

Your grade: B-

Your grade: B

Your grade: B+

Your grade: A-

Your grade: A

Your grade: A+

1. Question

2. Question

3. Question

4. Question

5. Question

Thyroid Metabolism

6. Question

7. Question

8. Question

9. Question

10. Question

11. Question

12. Question

13. Question

14. Question

15. Question

16. Question