Thyroid Pathology

Question 1

What is the essential action of thyroid hormones?

Answer 1

Increase in basal metabolic rate

Question 2

What effect does T3 have on the liver?

Answer 2

Increased cholesterol synthesis, cholesterol reabsorption from plasma, conversion of cholesterol to bile acids, fat oxidation/synthesis and gluconeogenesis

Question 3

What effect does T3 have on the adipose?

Answer 3

Increase FA mobilization

Question 4

What effect does T3 have on the heart?

Answer 4

Increase HR and hypertrophy

Question 5

What effect does T3 have on the pituitary gland?

Answer 5

Decreases TSH production and increases GH

Question 6

What effect does T3 have on the skeletal M?

Answer 6

Increases protein catabolism, glucose utilization and fat oxidation

Question 7

What effect does T3 have on bone?

Answer 7

Increased growth, maturation and resorption

Question 8

What is synthesized and stored in colloid?

Answer 8

Thyroglobulin (Tg)

Question 9

What can cause secondary hyperthyroidism?

Answer 9

Pituitary adenoma (secreting TSH)

Question 10

What are the lab values associated with primary hyperthyroidism?

Answer 10

Low TSH and elevated T3/4

Question 11

What are the lab values associated with secondary hyperthyroidism?

Answer 11

Elevated TSH and T3/4

Question 12

What are some causes of primary hypothyroidism?

Answer 12

Genetic defects in thyroid development, thyroid hormone resistance syndrome, postablative (surgery, radioiodine therapy, irradiation), autoimmune hypothyroidism, iodide deficiency, drugs (lithium, iodides, p-aminosalicylic acid), congenital biosynthetic defect

Question 13

What are some causes of secondary hypothyroidism?

Answer 13

Pituitary or hypothalamic failure

Question 14

What are the signs and sx associated with hypothyroidism in the adult/older child (myxedema)?

Answer 14

Dry brittle hair, hair loss, edema of face and eyelids, cold intolerance, diminished perspiration, coarse, cool, dry yellowish skin, lethargy, memory impairment, slow cerebration, thick tongue, slow speech, deep coarse voice, enlarged heart, poor heart sounds, diastolic HTN

Question 15

What can radioisotope scanning determine?

Answer 15

If a specific nodule is responsible for hyper function; if so, it can be treated with excision or ablation (hot nodules)

Question 16

Cold nodules are more likely to be what?

Answer 16

Neoplastic, but US and FNA are more useful in that workup

Question 17

FNA can be used to determine what?

Answer 17

Cellular constituents of a nodule

Question 18

What is the clinical management when there is insufficient information for a dx after FNA of a cold nodule?

Answer 18

Repeat FNA

Question 19

What is the clinical management for benign cytology of a cold nodule?

Answer 19

Clinical discretion (follow)

Question 20

What is the clinical management for AUS cytology of a cold nodule?

Answer 20

Repeat FNA

Question 21

What is the clinical management for cytology that is suspicious for follicular or Hurthle cell neoplasm?

Answer 21

Hemithyroidectomy

Question 22

What is the clinical management for cytology of a cold nodule that is suspicious for malignancy?

Answer 22

Hemithyroidectomy or near total thyroidectomy

Question 23

What is the clinical management for malignant cytology of a cold nodule?

Answer 23

Near total thyroidectomy +/- central LN dissection

Question 24

What are the treatment options for differentiated thyroid carcinoma?

Answer 24

Surgery or radioactive iodine (I^131); chemotherapy if refractory

Question 25

What is the function of C cells?

Answer 25

Responsible for calcitonin secretion