Thyroid Disorders

Question 1

What regulates the amount of thyroid hormone that reaches the fetus?

Answer 1

placenta

Question 2

Thyroid hormone abnormalities negatively affect what aspects of growth/aging in children?

Answer 2

bone
mental age
height

Question 3

What are common symptoms (or patient complaints) associated with hypothyroidism?

Answer 3

1. fatigue/weakness
2. dry/coarse skin
3. feeling cold
4. hair loss
5. memory
6. constipation
7. wt gain (poor appetite)
8. menorrhagia

Question 4

What are common physical signs associated with hypothyroidism?

Answer 4

1. puffy face/hands/feet
2. diffuse alopecia
3. bradycardia
4. peripheral edema
5. carpal tunnel syndrome
6. serous cavity effusions
7. delayed tendon reflex relaxation

Question 5

What are common symptoms (or patient complaints) associated with hyperthyroidism?

Answer 5

1. fatigue/weakness
2. hyperactivity
3. irritability/dysphoria
4. heat intolerance or sweating
5. palpitations
6. wt loss with increased appetite
7. diarrhea
8. oligomenorrhea
9. loss of libido

Question 6

What are common physical signs associated with hyperthyroidism?

Answer 6

1. tachycardia
2. a-fib in elderly
3. tremor
4. goiter
5. warm/moist skin
6. muscle weakness, prox myopathy
7. lid retraction

Question 7

What labs are used to assess thyroid function? (Which of these is most useful?)

Answer 7

TSH***
T4 (total + free)
T3 (total + free)
T3 index

Question 8

What are possible causes of inappropriate TSH labs, which point to hyperthyroidism?

Answer 8

TSH secreting pituitary adenoma

isolated pituitary resistance to thyroid hormone

Question 9

What are possible causes of inappropriate TSH labs, which point to euthyroid?

Answer 9

systemic illness

generalized resistance to thyroid hormone

assay interference

Question 10

What are possible causes of inappropriate TSH labs, which point to hypothyroidism?

Answer 10

central hypothyroidism

Question 11

Why don’t you see changes in T4 quickly in response to therapy?

Answer 11

T4 has a long half life, 6.2 days

Question 12

Why do you see changes in T3 quickly in response to therapy?

Answer 12

T3 has a short half-life, 1 day

Question 13

What are endogenous causes of hyperthyroidism?

Answer 13

1. Graves
2. toxic multinodular goiter
3. toxic adenoma
4. activating mutation of TSH receptor or Gs(alpha)
5. strauma ovarii
6. thyroiditis
7. secondary hyperthyroidism

Question 14

What are the causes of primary hypothyroidism?

Answer 14

1. thyroiditis
2. RIA trx for Graves
3. thyroidectomy
4. excessive iodine intake
5. iodine deficiency
6. inborne errors of TH synthesis
7. drugs

Question 15

What drugs cause primary hypothyroidism?

Answer 15

Li
amiodarone
interferon-alpha

Question 16

How is thyroiditis classified?

Answer 16

1. acute
2. subacute
3. silent
4. Riedel’s thyroiditis

Question 17

Causes of thyroid enlargement:

Answer 17

• -Diffuse nontoxic (simple) goiter
• -Nontoxic multinodular goiter
• -Toxic multinodular goiter
• -Hyperfunctioning solitary nodule
• -Thyroid neoplasm/cancer

Question 18

How is thyroid cancer classified?

Answer 18

• -Well differentiated (Papillary, Follicular)
• -Anaplastic
• -Thyroid lymphoma
• -Medullary thyroid carcinoma

Question 19

What are the risk factors for thyroid cancer?

Answer 19

• -Hx of head/neck radiation
• -M, < 20 or > 45 y/o
• -New or enlarging neck mass
• -Hoarse voice/vocal cord paralysis
• -Iodine deficiency
• -Family history of thyroid cancer or MEN 2

Question 20

What characteristics of thyroid nodules are at increased thyroid cancer risk?

Answer 20

• -nodule >4 cm
• -fixed to adjacent structures
• -new/enlarging
• -Extra-thyroidal extension
• -Suspected lymph node involvement