Thyroid Flashcards
how is T3 made
TRH released from hypothalamus
TSH released from anterior pituitary
acts on thyroid to release T4 the precursor of T3
t4 half life
8 days
t3 half life
1 day
hypothyroid parameters*
low t4
low/normal ts
high TSH
low serum thyroglobulin
hyperthyroid parameters
high t4 and t3
low TSH
high serum thyroglobulin
cause of hasimotos thyroiditis
antibodies against thyroglobulin and thyroid peroxidase that destroy thyroid gland particles
often misfdiagnosed as depression or anxiety
hasimotos thyroiditis
diagnosis of hasimotos thyroiditis
enlarge thyroid gland detected by ultrasound or radioactive uptake scan
need aspiration of gland detects macrophages and leukocytes
antibodies in blood test
caution of thyroid hormones
increase sensitivity to catecholamines
cause of graves disease
activating antibodies for TSH
contraindication for radio iodine
children and pregnancy
precautions for radioiodine
hypothyroidism
thyroid cancer
radiation induced thyroiditis
delay in therapeutic response
thioamide mechanism of action
inhibits thyroid hormone synthesis
interferes with organification of iodine
blocks conversion of MIT to DIT
inhibit coupling of iodinated tyrosines
polythiouracil mechanism of action
inhibits conversion of T4 to T3
fast decrease in T3
preferred treatment in pregnancy
polythiouracil
thioamine drug side effects
arthritis like rash fever leukopenia - dont monitor WBC levels, stop therapy at first sign of sore throat agranulocytosis
what are symptoms of a thyroid storm
shortnss of breath anxiety increased body temp sweating tachycardia chest pain
drug to decrease cardiovascular symptoms
propranolol
dexamethasone effects
inhibits conversion of t4 to t3
lithium effects
inhibits secretion adn degradation in peripheral tissues
sulfonamide effects
interfere with organification of iodine
sodium nitroprusside effects
thiocyanate accumulation inhibits iodine reuptake by the thyroid
amiodarone effects
contains lots of iodide
iodide in large doses effects
decreases degranulation of thyroglobulin and gland vascularity, usefull prior to surgery