SECRETS Endo - Thyroid Flashcards
hyperthyroidism sx
unintentional weight loss despite normal food intake diarrhea fatigue heat intolerance sweat, palpitations tremors increased pulse pressure
hyperthyroidism causes - permanent, transient
Graves disease **
toxic multinodular goiter
toxic adenoma (plummer’s disease)
pituitary adenoma
autoimmune thyroiditis subacute thyroiditis iodine induced struma ovarii thyrotoxicosis factitia trophoblastic tumors
hyperT diffuse uptake radioiodine
graves
trophoblastic tumors
hyperT nodular uptake radioiodine
toxic multinodular goiter toxic adenoma (plummers)
hyperT suppressed uptake radioiodine
autoimmune thyroiditis (Hashimoto) subacute thyroiditis (de Quervain) iodine-induced (Jod-Basedow) Thyrotoxicosis factitia struma ovarii
T3 & BMR
increase BMR
increase expression of Na/K-ATPase
produce glycolytic enzymes
weight loss, heat intolerance
T4 –> T3
peripheral conversion
5’-deiodinase
T4/T3 synthesis
- uptake iodine ion into follicular cells & colloid via iodide pump
- thyroid peroxidase oxidizes iodide –> iodine
- organification = iodine attached to tyrosine residues on thyroglobulin via thyroid peroxidase
- endocytosis of thyroglobulin back into follicular cells
- hydrolysis = T4, T3
- diffusion across plasma membrane into circulation
TH - catecholamines
increase expression of adrenergic receptors = increased sensitivity to catecholamines
direct stimulating effect on heart (+ HR, contractility)
+ SV
- diastolic pressure (vasodilation)
increased pulse pressure
tx sympathomimetic effects of hyperT
beta blockers
otherwise, a fib & osteoporosis
graves disease sx
exophthalmos
pretibial myxedema
antibodies IgG to TSH receptor
diffusely enlarged thyroid
pretibial myxedema
nonpitting
accumulation of interstitial GAGs within dermis
also seen in severe hypothyroidism
tx primary hyperT
meds = thionamides (PTU, methimazole)
surgery
radioactive iodine ablation
waiting
PTU vs methimazole
both inhibit thyroid synthesis
PTU also prevents peripheral deiodination of T4–>T3
tx thyroid storm
both cross placenta but can be used in pregnancy
ADR fatal agranulocytosis, often preceded by sore throat
thyroid storm
excessive levels of TH
substantial increase in BMR and extreme fever
fatal
Wolff-Chaikoff effect
large amounts of iodine decrease vascularity in thyroid
give before surgery to avoid complications
exquisitely tender thyroid
de Quervain thyroiditis
hypothyroidism sx
weight gin, fatigue, menorrhagia
constipation
cold intolerance
yellow skin
pallor, psychomotor retardation
drugs that cause hypothyroidism
lithium
amiodarone
hyper–>hypothyroidism
hashimoto
de quervain
woody consistency of thyroid gland
reidel’s thyroiditis = fibrosis of gland
sick euthyroid syndrome
abnormalities in thyroid fxn in ill patients without underlying thyroid or pituitary disease
causes hypothyroidism
hashimoto
de quervain
reidel’s
cretinism
hashimoto thyroiditis labs
antimicrosomal (antiperoxidase) antibodies
biopsy with lymphocytic infiltration of thyroid gland
assoc with autoimmune conditions like pernicious anemia
myxedema coma
profound lethargy, coma, weakness, hypothermia, hypoventilation, hypoglycemia, hyponatremia
thyroidectomy –> cramps, paresthesias
accidental removal of parathyroid glands –> hypocalcemia
tx hypothyroidism
levothyroxine
thyroid at back of tongue
thyroid fails to migrate appropriately to neck along thyroglossal duct
persistence of duct = cyst
newborns + thyroid hormone
hypothyroidism = preventable cause of mental retardation
TH necessary for normal CNS development
