Flashcards in thyroid Deck (14):
thyroglossal duct cyst
cystic dilation of thyroglossal duct remanant
presents as anterior neck mass
persistence of thyroid tissue at the base of the tongue: base of tongue mass
increased basal metabolic rate: incr. synthesis of sodium potassium ATPase
incr. sympathetic nervious sytem: incr. expression of beta receptors
clnical features of hyperhyroidism
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
IgG antibody that stimulates TSH receptor: incr. production and release of thyroid hormone
classically in women of child bearing age
clinical features of graves
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.
histo of graves
scalloping of the colloid and follicle hyperplasia.
incr. total and free T4, decr. TSH, hypocholesterolemia, incr. glucose
Tx for graves
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
What does the thyroid do?
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
elevated catecholamines and massive hormones, usually related to stress (childbirth, surgery)
delirium, diarrhea, tachyarrhythmia, hyperthermia, and vomiting with hypovolemic shock
Tx of thyroid storm
PTU (propylthiouriacil), BBs, and steroids (prednisone)
PTU inhibits peroxidase mediated oxidation, organification. also stops peripheral conversion of T4 to T3.
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.