Thyroid Flashcards
what is the needed component to make thyroid hormones?
iodine
explain the negative feedback loop with T3 and T4:
the hypothalamus makes TRH which activates the anterior pituitary.
the anterior pituitary makes TSH which activates the thyroid gland.
the thyroid gland makes T4 and then turns it into T3.
T3 suppresses the action of the hypothalamus and anterior pituitary.
what types of thyroid problems are the most common?
primary
are men or women more likely to have a thyroid dysfunction?
women
what is a goiter?
an enlargement of the thyroid gland with or without symptoms of thyroid dysfunction
what are the possible causes of a goiter?
excess TSH from anterior pituitary
low iodine levels (which causes a compensatory increase in TSH)
goitrogens (ex: lithium)
what is primary hypothyroidism?
insufficient T3 and T4 due to the thyroid not secreting (will see a high TSH but low T3 and T4)
what is secondary hypothyroidism?
the anterior pituitary isn’t secreting enough TSH (will see LOW TSH and low T3 and T4)
is hashimoto’s thyroiditis hypo- or hyper- thyroidism?
hypo
what is the hallmark antibody in hashimoto’s?
antithyroperoxidase (this is an autoantibody against the thyroid gland)
what are the risk factors for hypothyroidism?
female
> 50
white
pregnant
autoimmune disease
family hx
medications - amiodarone, lithium
hx of HYPERthyroidism treatments
what are the early clinical manifestations of hypothyroidism?
cold intolerance
weight gain
lethargy, fatigue
poor attention span
memory problems
increased cholesterol
muscle cramps
higher carotene level - yellowing skin
constipation
decreased fertility
what are the later clinical manifestations of hypothyroidism?
below normal temperature
bradycardia
weight gain (still)
decreased LOC
thickened skin (slowed down skin turnover)
cardiomegaly (d/t decreased HR and stroke volume, blood is backing up)
puffy face, hair loss, brittle nails
what is myxedema?
dermatological change that occurs with untreated hypothyroidism - can seen thickening of the skin and severe hair loss
what would lab values show for a patient with hypothyroidism?
high / low TSH (depends on cause)
low T3 and T4
anti - thyroglobulin antibody present
anti - thryoperoxidase antibody present