34 - Thyroid Disorders Flashcards
more common in what gender
women
Hypothyroidism is an ______ TSH level
elevated
What is subclinical hypothyroidism?
defined by an elevated TSH with normal thyroid hormone levels
Symptoms of hypothyroidism
fatigue, impaired memory, bradycardia, dry skin and hair, constipation, cold intolerance
What does dessicated thyroid contain?
both t4 and t3
Hypothyroidism:
What is the treatment of choice?
Levothyroxine (L-T4) to normalize TSH level
Hypothyroidism:
Dose adjust for levothyroxine every ____ weeks as needed
4-6
Hypothyroidism:
Dose of levothyroxine in adults
1.6 mcg/kg/day
Hypothyroidism:
Dose of levothyroxine in newborns
10-16 mcg/kg/day
Hypothyroidism:
When do you give liothyronine (T3) ?
short term management of patients with thyroid cancer undergoing withdrawal of L-T4 when recombinant TSH is not an option or in order to prepare for radioactive iodine therapy
Hypothyroidism in Pregnancy:
How do you manage women who are already taking thyroid hormone replacement therapy?
- increase the dose by 2 extra tabs/week immediately after a positive pregnancy test
- further dose adjustments based on TSH levels
Hypothyroidism in Pregnancy:
When do you get TSH levels drawn?
-have TSH levels q 6 weeks or 4 weeks after dose adjustment
Hypothyroidism in Pregnancy:
For those not on therapy, what is the target TSH?
TSH should be maintained at < 4 mU/L
Hypothyroidism in Pregnancy:
When would you initiate therapy if they’re not on it already?
if the TSH > 10 mU/L or if the patient has TSH > 4 mU/L and is positive for anti-TPO antibodies then you want to initiate thyroid replacement therapy
Hypothyroidism:
How do you explain the safety of thyroid replacement in pregnancy and breastfeeding?
thyroid replacement is completely safe in pregnancy and breastfeeding and is important to ensure a healthy pregnancy and normal fetal development
Hypothyroidism in Breastfeeding:
How do you treat it?
same as non-breastfeeding women
Thyrotoxicosis is also caused ______
hyperthyroidism
Hyperthyroidism is when TSH is ____
low
Define subclinical hyperthyroidism
TSH is low but thyroid hormone levels are normal
Symptoms of hyperthyroidism
weight loss, palpitations, diarrhea, heat intolerance, anxiety
What drugs can suppress TSH
corticosteroids, domperidone, metoclopramide, dopamine
Hyperthyroidism:
What can radioactive iodine cause as a side effect?
hypothyroidism
Hyperthyroidism:
Radioactive iodine is CI in ____
pregnancy
Hyperthyroidism:
What are the 2 antithyroid drugs?
- methimazole
- PTU
Hyperthyroidism:
How do antithyroid drugs work?
decrease production of thyroid hormone
Hyperthyroidism:
What can PTU also do?
block conversion of L-T4 to T3
Hyperthyroidism:
When do antithyroid drugs need to be stopped?
Need to be stopped 5 days prior to a thyroid scan or treatment with iodine
Hyperthyroidism:
Which antithyroid drugs is preferred? Why?
MTZ is preferred due to lower incidence of hepatotoxicity
Hyperthyroidism:
In what situation is PTU preferred over MTZ?
1st trimester of pregnancy
Hyperthyroidism:
How do beta blockers work?
ameliorate the symptoms of adrenergic excess and are usually used adjunctively in the management of Graves disease or toxic nodules
Hyperthyroidism:
Which beta blockers can decrease conversion of L-T4 to T3
propranolol and nadolol
Hyperthyroidism:
How does iodine (Lugol solution) work?
blocks thyroid hormone production
Hyperthyroidism:
When should iodine (Lugol solution) be given in relation to antithyroid drugs?
1 hour after administration of an antithyroid drug
Hyperthyroidism:
What can methimazole and PTU cause?
neutropenia
Hyperthyroidism:
How can corticosteroids help?
they lower the level of free T3
Hyperthyroidism:
Place of selenium in therapy?
Selenium 100mcg BId may prevent worsening of mild Graves orbitopathy and can be considered as supplemental therapy
How do you treat thyroid storm?
- antithyroid meds, BB and corticosteroids
- use acetaminophen for hyperthermia
- plasmapheresis can be considered in unresponsive cases
Hyperthyroidism and Pregnancy:
Wait how long after radioactive iodine before conceiving ?
6 months
Hyperthyroidism and Pregnancy:
____ is preferred antithyroid for 1st trimester of pregnancy
PTU
Hyperthyroidism and Pregnancy:
Can you give MTZ?
if PTU is CI
Hyperthyroidism and Pregnancy:
What is the treatment for 2nd and 3rd trimester?
MTZ
Hyperthyroidism and Pregnancy:
What are some other options?
BBs or iodine in 1st trimester with careful monitoring
Hyperthyroidism and Pregnancy:
What do you monitor and how often?
TSH, fT3, fT4 q6-8 weeks
Hyperthyroidism and Pregnancy:
What do you need to measure at 22 weeks gestation
TRAb titre should be measured
-if positive, repeat at 30-34 weeks
Hyperthyroidism and Pregnancy:
A high titre of TRAb means what?
increased risk of hyperthyroidism for the baby
When on antithyroid drugs, when will neutropenia be seen if it happens?
1st 90 days
When on antithyroid drugs, when will hepatic effects be seen if it happens?
1st 120 days
Hyperthyroidism and Breastfeeding:
What antithyroid drug is preferred?
- MTZ preferred but can use PTU
- can use BBs
