Wk 8. Thyroid Disorders

Question 1

What two hormones does the thyroid produce?

Answer 1

Triiodothyronine T3

Thyroxine T4

Question 2

2. Which thyroid hormone is converted in the periphery?

Answer 2

T4 is converted to T3

Question 3

3. Which thyroid hormone is more potent?

Answer 3

T3

Question 4

4. Describe the steps of thyroid hormone regulation. (TRH, TSH, T3, T4, negative feedback loop)

Answer 4

TRH from hypothalamus TSH from anterior pituitary T3 & T4 from thyroid inhibit TSH from anterior pituitary

Question 5

5. Describe the relationship of TSH levels to T3 and T4 levels.

Answer 5

Low T3 or T4 increases TSH, high T3 or T4 lowers TSH

Question 6

6. Describe common clinical signs and symptoms of hypothyroidism?

Answer 6

Goiter; puffy, expressionless face; cold/dry skin; brittle hair; hair loss from scalp & outer half of eyebrows; fatigue; irritability; depression; lack of concentration; cold intolerance; constipation; heavy menses; increased cholesterol

Question 7

7. Persons over 50 years of age may need what change in the initial dose of levothyroxine?

Answer 7

Lowered

Question 8

8. Discuss the effects on the fetus of maternal hypothyroidism in pregnancy. A person treated for hypothyroidism may need to increase the dose of levothyroxine by how much?

Answer 8

Decreased IQ and neuropsychological function of the child. Increase levothyroxine dose by up to 50%.

Question 9

9. Discuss the effects of congenital hypothyroidism in infants.

Answer 9

Mental retardation, large tongue, pot belly, dwarfish stature, derangement of growth - nerves, muscles, bone, teeth

Question 10

10. How long until levothyroxine reaches a plateau?

Answer 10

One month

Question 11

11. Levothyroxine should be given with or without food?

Answer 11

Without food

Question 12

12. Discuss the expected change in TSH when a patient is responding to levothyroxine.

Answer 12

TSH decreases to normal levels

Question 13

13. Describe the signs and symptoms of thyrotoxicosis.

Answer 13

Tachycardia, angina, tremor, nervousness, insomnia, hyperthermia, heat intolerance, sweating, abdominal cramping, weight loss, increased appetite, menstrual irregularities

Question 14

14. Which drugs can cause decreased absorption of levothyroxine? How many hours after the administration of levothyroxine may these drugs be given?

Answer 14

H2-recptor blockers, proton pump inhibitors, bile-acid sequestrants such as colestyramine (Questran) and colestipol (Colestid); sucralfate (Carafate); calcium, iron, magnesium, aluminum.
4 hours.

Question 15

15. Why would a nurse administer levothyroxine with caution to a patient on warfarin?

Answer 15

Levothyroxine increases the degradation of Vitamin K-dependent clotting factors and may increase the chance of bleeding. May need to decrease dose of warfarin.

Question 16

16. What is the interaction between catecholamines and levothyroxine?

Answer 16

Levothyroxine increases the body’s response to epinephrine, norepinephrine, and dopamine.

Question 17

17. Why might liothyronine (Cytomel) be given instead of levothyroxine (Levothyroid)?

Answer 17

Rapid onset of action in myxedema coma.

Question 18

18. Discuss the nursing care of a patient with hypothyroidism.

Answer 18

Life-long replacement; take on an empty stomach; monitor for hypothyroidism & hyperthyroidism; hold levothyroxine if pulse >100/min & call primary care provider; monitor TSH, T3 & T4; minimize adverse drug interactions; monitor warfarin levels.

Question 19

19. What are the symptoms of thyrotoxic crisis (thyroid storm)? What usually triggers it?

Answer 19

Restlessness, agitation, tremor, severe tachycardia, hypotension, heart failure, hyperthermia, profound weakness, unconsciousness, coma.
Severe illness or major surgery.

Question 20

20. What mimics TSH in patients with Grave’s Disease?

Answer 20

Thyroid-stimulating immunoglobulins (TSI)

Question 21

21. What are some signs and symptoms of Grave’s Disease?

Answer 21

Rapid, strong heartbeat; rapid thoughts & speech; trouble concentrating; tremor; insomnia; weakened muscles; increased body temperature; warm, moist skin; increased appetite with weight loss; diarrhea; exophthalmos.

Question 22

22. What TSH level is expected with hyperthyroidism?

Answer 22

Decreased TSH

Question 23

23. Give two ways propylthiouracil (PTU) works in hyperthyroidism?

Answer 23

Inhibits thyroid hormone synthesis by inhibiting peroxidase. Suppresses conversion of T4 to T3 in the periphery.

Question 24

24. Name a blood disorder caused by thionamides?

Answer 24

Agranulocytosis – may see sore throat or fever.

Question 25

25. What may happen to thyroid hormone production after the use of a thionamide?

Answer 25

Hypothyroidism

Question 26

26. How does Tapazole (methimazole) work differently from PTU?

Answer 26

Inhibits thyroid hormone synthesis, but does not block T4 or T3 in the periphery.

Question 27

27. LOW-dose iodine-131 causes which delayed adverse effect?

Answer 27

Hypothyroidism

Question 28

28. What precautions should be taken with persons undergoing HIGH-dose iodine-131?

Answer 28

Stay 3-6 feet from patient; only 30 min of contact per day; double flush urine and secretions down toilet; have patient increase fluids and void frequently.

Question 29

29. How does an iodine solution work?

Answer 29

Inhibits synthesis and release of thyroid hormones.

Question 30

30. At what heart rate would the nurse hold the levothyroxine and call the prescriber?

Answer 30

Hold if >100/min