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
what is primary hyperthyroidism?
overproduction of T3 and T4 directly from the thyroid gland (otherwise known as graves disease - which is autoimmune, this is the most common type)
what is secondary hyperthyroidism?
overproduction of T3 and T4 d/t excess TSH from the anterior pituitary
what is tertiary hyperthyroidism?
overproduction of T3 and T4 d/t excess thyrotropin releasing hormone from the hypothalamus
what are the risk factors for hyperthyroidism?
family hx of graves disease
> 40
women
white
amiodarone
excessive iodine intake
pregnancy
what are clinical manifestations of graves disease?
nervousness
insomnia
sensitivity to heat
weight loss
enlarged and palpable gland
audible bruit over thyroid gland d/t increased glandular blood flow
afib
HF
myxedema (not common)
exophthalmos (increase eye doctor appts)
diagnosis for hyperthyroidism could include what?
low TSH
high T3 and T4
ultrasound with color doppler eval - shows increased blood flow
radioactive iodine scanning and measurement of iodine intake (would show increased intake)
what are the treatment options for hyperthyroidism?
anti-thyroid medication - propylthiouracil (PTU) (this blocks conversion of T4 to T3
radioactive iodine treatment
thyroid removal
what needs to be monitored if a patient is on PTU for hyperthyroidism?
liver enzymes, this drug is hepatotoxic
what is a thyrotoxic crisis (otherwise known as a thyroid storm)?
an overwhelming release of thyroid hormones that exerts an intense stimulus on the metabolism, commonly precipitated by surgery, infection, or trauma.
what is the parathyroid responsible for?
controlling calcium levels in the body, promoting vitamin D production in the kidneys \
what are the clinical manifestations of hypoparathyroidism?
basically HYPOcalcemia
muscle cramps
irritability
tetany
convulsions
trousseau and chvostek sign
what is the typical treatment for hypoparathyroidism?
replace parathyroid hormone
normalize calcium and vitamin D levels
what are the clinical manifestations of hyperparathyroidism?
basically HYPERcalcemia
muscle weakness
poor concentration
neuropathy
HTN
kindey stones
metabolic acidosis
osteopenia
pathological fractures
constipation
depression, confusion, subtle cognitive defects
what are the typical treatments for hyperparathyroidism?
reducing levels of calcium
diuretics
calcitonin
bisphosphonates
vitamin D
surgical intervention
