thyroid

Question 1

thyroglossal duct cyst

Answer 1

cystic dilation of thyroglossal duct remanant

presents as anterior neck mass

Question 2

lingual thyroid

Answer 2

persistence of thyroid tissue at the base of the tongue: base of tongue mass

Question 3

hyperthyroid

Answer 3

increased basal metabolic rate: incr. synthesis of sodium potassium ATPase
incr. sympathetic nervious sytem: incr. expression of beta receptors

Question 4

clnical features of hyperhyroidism

Answer 4

weight loss, incr. appetite, heat intolerance and sweating, tachycardia, arrythmia, tremor, insomnia, diarrhea, oligomenorrhea, bone resorption with hypercalcemia, hypocholesterolemia, hyperglcemia, decr. muscle mas w/ weakness

Question 5

graves disease

Answer 5

IgG antibody that stimulates TSH receptor: incr. production and release of thyroid hormone
classically in women of child bearing age

Question 6

clinical features of graves

Answer 6

hyperthyroidism, diffuse goiter, exophthalmos and pretibial myxedema.
Exopthalmos and pretibial myxedema are NOT due to excess thyroid hormone, but excess glycosaminoglycans.
fibroblasts behind eye and over the shin secrete excess GAGs in response to the antibody that stimulates the TSH receptor (which is also present in these two locations).
Myxedema- edema due to glycosaminoglycans.

Question 7

histo of graves

Answer 7

scalloping of the colloid and follicle hyperplasia.

Question 8

graves labs

Answer 8

incr. total and free T4, decr. TSH, hypocholesterolemia, incr. glucose

Question 9

Tx for graves

Answer 9

BBs, thioamide (blocks peroxidase and production of thyroid hormone), radioiodine (taken up by follicular cells of thyroid)
drug names: propanylthiouracil, methimazole
both block throid peroxidase; propanylthiouracil also blocks 5’-deoidinase

Question 10

What does the thyroid do?

Answer 10

tyrosine to thyroglobulin. Pushes TG to follicular lumen
also takes in iodine
togeter, thyroglobuline and I2 added together in organification. makes MIT and DIT.
MIT + DIT = T3
DIT + DIT = T4
all catalyzed by peroxidase

Question 11

thyroid storm

Answer 11

elevated catecholamines and massive hormones, usually related to stress (childbirth, surgery)
delirium, diarrhea, tachyarrhythmia, hyperthermia, and vomiting with hypovolemic shock

Question 12

Tx of thyroid storm

Answer 12

PTU (propylthiouriacil), BBs, and steroids (prednisone)

PTU inhibits peroxidase mediated oxidation, organification. also stops peripheral conversion of T4 to T3.

Question 13

multinodule goiter

Answer 13

enlarged thyroid gland with multiple nodules
d/t relative iodine deficiency
usually non-toxic- pts are euthyroid
but, rarely, regions become TSH-independent (toxic goiter and secrete thyroid hormone.

Question 14

Jod-Basedow phenomenon

Answer 14

thyrotoxicosis if a patient with iodine deficiency goiter is made iodine replete