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53 Cards in this Set

  • Front
  • Back
What are 3 main causes of hypothyroidism?
Hashimoto's thyroiditis
radioactive iodine
How long does it take to achieve steady state of levothyroxine?
about 4 wks
Which pts should be started on a lower levothyroxine dose?
>50 or with cardiac disease
How should synthroid be taken?
empty stomach with full glass of water at least 30 min before breatkfast
What might decrease the absorption of synthroid?
dietary fiber or soy protein supplements
When will the pt typically get resolution of symptoms after starting levothyroxine?
2-3wks; but check in 4-6
In which pts is the TSH misleading/worthless?
those w/central hypothyroidism (from hypothalamic or pituitary disease)
What are ADRs of levothyroxine?
s&s of hyperthyroidism (tremors, palpitations, anxiety, weight loss, tachycardia, inc bowel movements)

cardiac arrythmias, angina, or MI, afib, osteoporosis (depending on risk factors/age/length of tx)
What is liothyronine?

shorter half-life than levothyroxine
not recommended
What is thyroid USP?
Armour thyroid - desiccated porcine thyroid tissue

100mcg of levothyroxine = 60mg (1grain) of armour

don't use it
What happens to free T4 in pg? what does this mean for tx?
decreases b/c elevated estrogen -> dec hepatic clearance of TBG; inc requirement for levothyroxine
how do you treat myxedema coma?
large doses of synthroid (sometimes use levothyroxine liothyronine combo in this case)

may also need hydrocortisone to avoid adrenal crisis
What is the most common cause of hyperthyroidism?
Grave's disease (autoimmune)
What is more commonly used, antithyroid drugs or radioactive iodine tx?
radioactive iodine
What are the two antithyroid drugs?
propylthiouracil (PTU) and methimazole
What class are PTU and methimazole in?
How do the thionamides work?
inhibit synthesis of thyroid hormone
Which thionamide interferes with conversion of T4 -> T3 at high doses?
Why is methimazole generally preferred over PTU?
can be given qd (instead of bid or tid like PTU)
What are the ADRs of thionamides?
immunoallergic hepatitis (only PTU)
ANCA positive vasculitis w/acute renal failure (PTU usually)
GI intolerance
What do you order if a pt taking a thionamide presents w/sore throat or fever?
CBC (b/c worried about agranulocytosis)
What do PTU and methimazole do to warfarin?
decrease effect -> need higher dose of warfarin
What might high concentrations of iodine be used for in thyroid tx?
severe thyrotoxicosis
thyroid storm
(rapid effects)
What is the treatment of choice for hyperthyroidism in pg?
Do thionamides cross the placenta?
What are the classic symptoms of thyroid storm?
fever, agitation, psychosis, tachycardia (>140), high-output HF, profuse sweating
Is PTU or methimazole preferred for thyroid storm?
PTU (b/c it blocks conversion of T3 to T4)
What mesd are linked to thyroid problems?
How do you treat euthyroid sick pt?
trick question: will resolve on its own
What effect does hypothyroidism have on the heart?
reduces CO
Which thyroid med has a higher ratio of T3:T4? (may cause T3 thyrotoxicosis)
Armour thyroid
What are the 4 most common causes of hyperthyroidism?
Toxic multinodular goiter
Autonomous nodule
What will hyperthyroidism do to the heart?
inc CO
inc myocardial oxygen demand
in HR
hyperdynamic precordium
inc contractility
What drugs are used to tx hyperthyroidism?
beta blockers
Which drug has a higher intrathyroidal concentration, methimazole or PTU?
Which lasts longer, methimazole or PTU?
What enzyme converts thyroine (T4) to triiodothyronine (T3) in extrathyroidal tissue?
Which is more likely to cause an ANCA positive vasculitis, methimazole or PTU?
Which steroid is most often used for short term symptomatic tx of hyperthyroidism?
Why is cholestyramine used for hyperthyroidism?
inhibits enterohepatic recycling of thyroid hormone
What restrictions are there before radioactive iodine for hyperthyroid?
must be off T3 for 2 weeks and T4 for 4 weeks

no IV contrast in 2-3mo (get a urine iodine level)
How long does it take for radioactive iodine to work?
2-12 weeks
Surgery is often last choice for hyperthyroidism but is first choice for these three things. . .
autonomous nodules
thyroid CA
When is thyroiditis common?
following viral illness
How is thyroiditis treated?
may offer beta blocker
do you treat thyroiditis with methimazole or PTU?
in thyroiditis which will normalize first, the FT4 or TSH?
What thyroid nodules are suggestive of CA?
inc vascularity
What is the most common thyroid CA?
TSH goal post papillary CA is ______, for medullary CA is ______
0-0.5 (suppressed for papillary)

"normal" (for medullary)
Does amiodarone cause hypo or hyperthyroidism more often?
What drug can cause hyperthyroidism resistant to tx?
There is 10x as much iodine in this daily drug than in a nL diet.