Endocrine 6

Question 1

Where does the thyroid diverticulum arise from and where does it go?

Answer 1

Floor of primitive pharynx and descneds into the neck

Question 2

How is the thyroid connected to the tongue?

Answer 2

Thyroglossal duct

Question 3

What happens when the thyroglossal duct persists?

Answer 3

Becomes the pyramidal lobe of thyroid

Question 4

What is th normal remnant of the thyroglossal duct?

Answer 4

Foramen cecum

Question 5

Where is the most common site of ectopic thyroid tissue?

Answer 5

Tongue

Question 6

Presentation of thyroglossal duct cyst?

Answer 6

Anterior midline neck mass that MOVES with swallowing.

Question 7

How is thyroid hormone formed?

Answer 7

1. Iodine is transported into cuboidal cells of the thyroid follicle. 2. Iodine combines with thyroglobulin via peroxidase forming MIT and DIT. 3. MIT and DIT form T4 and T3. 4. T4 is sent out and converted to more active T3 in the peripheral tissue via 5’deiodinase.

Question 8

Symptoms of Hyperthyroidism?

Answer 8

Heat intolerance, weight loss, inc appetitie, hyperactivity, diarrhea, inc reflexes, warm moist skin, fine hair, chest pain, palpitations, arrythmias, inc B-adrenergic receptors

Question 9

Lab findings in hyperthyroidism?

Answer 9

Dec TSH, Inc free or total T4, Inc Free or total T3

Question 10

Causes of Hyperthyroidism (Thyrotoxicosis)

Answer 10

1. Toxic multinodular goiter. 2. Graves’ disease. 3. Thyroid storm. 4. Struma ovarii teratoma. 5. Subacute thyroiditis (de Quervarian’s)

Question 11

Jod-Basedow phenomenon

Answer 11

When a pt with iodine deficient goiter gets thyrotoxicosis after iodine repletion (ex. recent study using IV iodine contrast)

Question 12

Toxic Multinodular Goiter

Answer 12

Focal patches of hyperfunctoining follicular cells working independently of TSH due to mutaiton in TSH receptor. Inc rel of T3 and T4. Multiple hot nodules.

Question 13

Are hot nodules malig?

Answer 13

No

Question 14

Cause of Graves’ Disease

Answer 14

Autoimmune hyperthyroidism w/ thyroid-stimulating IgG.

Question 15

Presentation of Graves’ Disease

Answer 15

Proptosis (exophthalmos), EOM swelling; pretibial myxedema; inc CT deposition; diffuse goiter

Question 16

Special lab findings in Graves’

Answer 16

Inc resin radioactive T3 uptake and inc radioactive iodine scan

Question 17

HLA assoc w/ Graves’?

Answer 17

HLADR3 and HLAB8

Question 18

Definitive rx for Graves’?

Answer 18

Thyroidectomy

Question 19

Pharmaceutical rx for hyperthyrodism?

Answer 19

1. Propylthiouracil. 2. Methimazol. 3. B-blockers. 4. Radioactive Iodine

Question 20

What is a thyroid storm?

Answer 20

Stress-induced catecholamine surge-> death (by arrythmia) and and coma.

Question 21

What is subacute thyroiditis (de Quervian)

Answer 21

Self-limited hypothyroidism following a flu-like illness (usually viral infexn). Begins w transient hyperthyroidism and becomes hyper. Histo: granulomatous inflammation. TENDER thyroid. Assoc w/ HLAB35

Question 22

Approach to Thyrotoxicosis

Answer 22

See SU 217

Question 23

What happens to thyroid hormone levels during preg?

Answer 23

Increase in thyroid binding globulin; inc free T4 and T4; normal free T4 and T3

Question 24

Single thyroid nodule and hyperthyroidism?

Answer 24

Toxic thyroid adenoma