Thyroid part I Flashcards
decreased levels t3T4 stimulate what
release of TRH from hypothalamus and TSH from anterior pituitary
increased T3 T4 levels cause what
decreased release of TRH and TSH
42 y.o increased sweating, pounding heart and weight loss
phyiscal exam reveals slightly enlarged nontender thyroid with no nodules
enlarged thyroid
signs of hyperthyroidism
wide eyed, staring gaze from overactivity SAN
What is Graves
hyperthyroidism with protruding eyeballs
what are the studies used in thyroid function testing
serum TSH and T4
US and radionucleotide uptake studies
serum Ab
if TSH is low and T4 high what is it
hyperthyroidism
if TSH is high and low T4
hypothyroidism
what will an US of thyroid tell you
cystic or solid
what will a toxic multinodular goiter look like on radionucleotide scan
lumpy bumpy in all different areas
what will graves look like on radionucleotide scan
increased uptake on both lobes of thyroid
what will a toxic adenoma look like on radionucleotide scan
one mass with increased density
what is thyrotoxicosis
hypermetabolic state caused by increased levels of free T3 and T4
what are the 3 most common casues of thyrotoxicosis
diffuse hyperplasia (Graves) hyperfuncitonal multinodular goiter hyperfunctional thyroid adenoma
what branch of SAN is turned up in hyperthyroidism
beta adrenergics
describe signs hyperthyroidsm
increased in basal metabolic rate, skin is warm and flushed from inc blood floww (vasodilation) heat intolerance, increased sweating, weigh loss despite increased appetite
what are the cardiac manifestations of hyperthyroidism
tachy, palpitations, cardiomegaly
arrhythmias, atrial fibrillation
some have L ventricular dysfuntion and low output HF “thyrotoxic cardiomyopathy”
what are signs from overactivity of SAN in hyperthyroidism
tremor, hyperreactivity, emotional lability, anxiety, inability to concentrate and insomnia
what GI Sx can you have if hyperthyroid
hypermotlity, diarrhea, malabsorption
what are the ocular changes contributed to hyperthyroidism
wide, staring gaze an lid lag
what can hyperthyroidism lead to in skel system
osteoporosis from increased resoprtion
what is the thyroid storm
short onset of severe hyperthyroidism
usually in Graves from acute elevation catecholamine levels
signs of thyroid storm
febrile, tachycardia
medical EM because can lead to cardiac arrhythmia
seondary causes of hyperthyroidism
TSH secreting pituitary adenoma
most common cause endogenous hyperthyroidism
Graves
pretibial myxeema
graves disease
what causes Graves
autoimmune disorder from autoAb against multiple thyroid proteins (TSH R)
what is most common Graves Ab subtype
TSImmunoglobulin which acts like TSH
what cells undergo the hyperplasia in hyperthyroid
the thyroid follicular epithelial cells
pale follicular lumen with scalloped margins and colloid
graves
audible bruit on thyroid
graves
what causes the exopthalmus in graves? complicaiton?
fat and inflammation taht push eye forward
can’t close lides- corneal abrasion
what is the pretibial myxedema seen in graves
scaly thickening and induration of skin on shins
patients with graves are at higher risk for what
SLE, pernicious anemia, type I DM, and addisons
lab findings in graves
increased free T3 T4 adn depressed TSH
Tx graves
beta blockers and thionamides, radioiodine ablation adn thyroidectomy
when is surgery used in graves
large goiters that are compressing surrounding structures
42 y.o weight gain, constipation and feeling cold
enlarged thyroid
hypothyroid
Lab testing for hashimoto hypothyroidism
TPO autoAb, TPO specific T cells, cytokines that lead to thyrocyte damage and thus decrease T4T3 even though increase TSH
when do you not do thyroid function testing
hospitalized paitent because sick sinus syndrome- will have abnormal values
pregnant women- abnormal thyroid function
what are primary causes of hypothyroidism
genetic defects thyriod hormone resistance syndrome postablative autoimmune iodine deficiency drugs congenital biosynthestic defect
what are the secondary causes of hypothyroidism
pituitary failure, hypothalamic failure
what is the ww cause of congenital hypothyroidism
endemic iodine deficiency in diet
what is the msot common cause of hypothyroidism in the iodine sufficient areas in world
autoimmune
what is cretinism
hypothyroidism that develops in infancy or early childhood
clinical features of cretinism
impaired development of the skeletal system and central nervous system:
mental retardation, short stature, coarse facial features, protruding tongue and umbilical hernia
severity of mental impairment in cretinism
related to time at which thyriod deficiency occurs in utero
when is a deficiecny in maternal thyroid hormone not at risk to baby in pregnancy
once fetal thyroid has become functional
myxedema
slowing of physical and mental activity
generalized fatigue, apathy, mental sluggishness (mimic depression)
speech and intellectual function slowed
listless, cold intolerant, overweight
skin of hypothyroid patients
cool and pale
wy is SOB a complain in hypothyroid
reduced CO
why is there an increased CV mortality rate in patients with hypothyroidism
promotes increase in total cholesterol and LDL levels
what causes nonpitting edema, coarsening facial features, enlargement of tongu and deepening of voice in hypothyroidism
accumulateion of gags and hyaluronic acid in skin, subq and viscera
what can cause painful thyroid
infecitous thyroiditis, subacute granulomatous thyroiditis
what are the non painful types of thyroiditis
subacute lymphcytic thyroiditis and fibrious thyroiditis
what are the 3 most common types thyroiditis
hashimoto
granulomatou thyroiditis
subacute lymphocytic thyroiditis
what will fine needle aspiration of hashimoto thyroid look like
lots of lymphocytes
Hurthle cells
thyroid follicles in hashimoto
what is hashitoxicosis
disruption of thyroid follicles, transient thyrotoxicosis before full blown hashimoto
hashimoto patients increase risk for
DM I, autoimmune adrenalitis, SLE, myasthenia gravis and sjogren syndrome
what malignancy are hashimoto patients at increased risk for
extranodal zone B cell lymphomas
