Thyroid (mine Flashcards
Exophthalmos
bulging of the eyes
most common cause Graves (hyper)
TPOAB
thyroid peroxidase antibody
what is the first and primary test done to check thyroid function
TSH
- esp if no history of thyroid illness but have symptoms
- if it is high or low, then consider checking thyroid panel
what condition would you expect in a person with a HIGH thyroid stimulating hormone (TSH)
high TSH indicates that you have low thyroid hormones
TSH is from the pituitary
what condition would you expect in a person with a HIGH thyroid stimulating hormone (TSH)
high TSH indicates that you have low thyroid hormones
TSH is from the pituitary
Conditions:
HYPOthyroidism (congenital=cretinism and primary)
secondary HYPERthyroidism
pituitary adenoma
hashimoto’s thyroditis (autoimmune)
amiodarone/ dopamine antagonist= drugs
ectopic TSH producing tumors
TSH producing pituitary adenoma
what condition would you expect in a person with LOW TSH
primary HYPERthyroidism
secondary HYPOthyroidism
- TSH near zero!!
Tertiary HYPO thyroidism
graves disease (autoimmune)- has no effect on TSH levels
glucocorticoids= drugs
excessive exogenous thyroid hormone
high levels of chronic gonadotropin
how much more active is T3 than T4
4-5 X more active
what are the indications of performing a TSH test
screening for congential hypothyroidism
diagnose hypothyroidism, hyperthyroidism, pituitary or hypothalamic dysfunction
differentiate primary (thyroid) hypothyroidism from secondary (pituitary) and tertiary (hypothalamus) hypothyroidism
what are the indications of performing a TSH test
screening for congential hypothyroidism
diagnose hypothyroidism, hyperthyroidism, pituitary or hypothalamic dysfunction
differentiate primary (thyroid) hypothyroidism from secondary (pituitary) and tertiary (hypothalamus) hypothyroidism
what is TSH also called
thyrotropin
what is the best test for screening of hypothyroid and hyperthyroid
!!!!
TSH
what is the best test for screening of hypothyroid and hyperthyroid
!!!!
TSH
if normal= no other test needed
what is it called when we treat hypothyroidism
levothyroxine treatment
aka the medication
what is it called when we treat hypothyroidism
levothyroxine treatment
aka the medication
what are the indications for Total T4 test
evaluates for hypo and hyper
newborn screening of congenital hypo
monitor therapy response for hypo or hyper
what is the drawback to Total T4 test
con be influenced by elevations or declines in serum proteins giving false assumption of low or high levels
what causes high total T4
excessive intake of iodine
hyperthyroidism (graves)
high doses of levothyroxine meds (for hypo Tx)
familial dysalbuminemic hyperthyroxinemia
hepatitis
what decreases total T4
hypothyroid
pituitary, hypothalamic and iodine insufficiencies
protein def
- nephrotic syndrome
- reduced TBG and albumin = reduced protein bound to T4
what are the indications for getting a free T4 test
evaluate signs of hypo or hyper
monitor Tx response of hypo or hyper
what causes elevations in free T4
primary HYPERthyroidism (graves)
acute thyroiditis (hashimotos) - initial excess T4
fictitious hyperthyroidism
what is fictitious hyperthyroidism
caused by treatment for hypo by too much levothyroxine
what causes decreased T4 levels
primary hypothyroidism
pituitary/hypothalamic/iodine insuf
Total T3
rarely checked
influenced by non thyroid diseases like liver problems
why check Total T3
mainly to assist in diagnosis of hyper
suspected T3 toxicosis (rare)
administering drugs that interfere with conversion of T4 to T3 (amiodarone)
what causes elevation in free T3
high altitude
HYPERTHYROIDISM
T3 toxicosis
what causes decreased Free T3
HYPOTHYROIDISM
malnutrition (iodine def)
late pregnancy
what test do we run if patient has no symptoms, but a decreased free T4 and is suspected of having a hereditary condition that would cause an increase in TBG
TBG test would be run
would also run to assess thyroid cancer
when to order TgAB
in addition to TPOAb and TRAb for evaluating autoimmune thyroid disesase
or monitor cancer
what are the two types of TRAb tests
TSI= thyroid stimulating immunoglbulin antibody
- measures net activity of TRAb
- good for graves and goiter
TBII- TSH receptor binding inhibiotr immunoglobulin
when do you order TSI and TBII
for patients with extrathyroidal manifestations like exophtalmos but have a euthyroid
what conditions do you see an increase in radioactive iodine uptake
graves
plummer disease (toxic multinodular goiter)
toxic adenoma (uninodular goiter)
thyroiditis (early hashimoto)
what casues RAIU to decrease
hypo
thyroiditis late stages
iodine induced hyperthyroidism
drugs
who to check thyroid labs on
newbors for congenital hypo screening (TSH only) screen pt with hyperlipidemia unknown cause of hyponatremia consider hypertensive pt
what does hypothyroidism cause in infants
irreversible damage to CNS
developmental defects
mental retardation
Tx is levothyroxine
what to do if you get a low TSH
repeat TSH and check free T4 and T3 (thyroid panel)
if TSH normal, free T4/3 normal= lab error
if TSH low and free T4/3 high= hyperthyroid
