SECRETS Endo - Thyroid

Question 1

hyperthyroidism sx

Answer 1

unintentional weight loss despite normal food intake
diarrhea
fatigue
heat intolerance
sweat, palpitations
tremors
increased pulse pressure

Question 2

hyperthyroidism causes - permanent, transient

Answer 2

Graves disease **
toxic multinodular goiter
toxic adenoma (plummer’s disease)
pituitary adenoma

autoimmune thyroiditis
subacute thyroiditis
iodine induced
struma ovarii
thyrotoxicosis factitia
trophoblastic tumors

Question 3

hyperT diffuse uptake radioiodine

Answer 3

graves

trophoblastic tumors

Question 4

hyperT nodular uptake radioiodine

Answer 4

toxic multinodular goiter
toxic adenoma (plummers)

Question 5

hyperT suppressed uptake radioiodine

Answer 5

autoimmune thyroiditis (Hashimoto)
subacute thyroiditis (de Quervain)
iodine-induced (Jod-Basedow)
Thyrotoxicosis factitia
struma ovarii

Question 6

T3 & BMR

Answer 6

increase BMR

increase expression of Na/K-ATPase

produce glycolytic enzymes

weight loss, heat intolerance

Question 7

T4 –> T3

Answer 7

peripheral conversion

5’-deiodinase

Question 8

T4/T3 synthesis

Answer 8

1. uptake iodine ion into follicular cells & colloid via iodide pump
2. thyroid peroxidase oxidizes iodide –> iodine
3. organification = iodine attached to tyrosine residues on thyroglobulin via thyroid peroxidase
4. endocytosis of thyroglobulin back into follicular cells
5. hydrolysis = T4, T3
6. diffusion across plasma membrane into circulation

Question 9

TH - catecholamines

Answer 9

increase expression of adrenergic receptors = increased sensitivity to catecholamines

direct stimulating effect on heart (+ HR, contractility)

+ SV
- diastolic pressure (vasodilation)

increased pulse pressure

Question 10

tx sympathomimetic effects of hyperT

Answer 10

beta blockers

otherwise, a fib & osteoporosis

Question 11

graves disease sx

Answer 11

exophthalmos
pretibial myxedema
antibodies IgG to TSH receptor
diffusely enlarged thyroid

Question 12

pretibial myxedema

Answer 12

nonpitting
accumulation of interstitial GAGs within dermis

also seen in severe hypothyroidism

Question 13

tx primary hyperT

Answer 13

meds = thionamides (PTU, methimazole)

surgery
radioactive iodine ablation
waiting

Question 14

PTU vs methimazole

Answer 14

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

Question 15

thyroid storm

Answer 15

excessive levels of TH
substantial increase in BMR and extreme fever
fatal

Question 16

Wolff-Chaikoff effect

Answer 16

large amounts of iodine decrease vascularity in thyroid

give before surgery to avoid complications

Question 17

exquisitely tender thyroid

Answer 17

de Quervain thyroiditis

Question 18

hypothyroidism sx

Answer 18

weight gin, fatigue, menorrhagia
constipation
cold intolerance
yellow skin

pallor, psychomotor retardation

Question 19

drugs that cause hypothyroidism

Answer 19

lithium

amiodarone

Question 20

hyper–>hypothyroidism

Answer 20

hashimoto

de quervain

Question 21

woody consistency of thyroid gland

Answer 21

reidel’s thyroiditis = fibrosis of gland

Question 22

sick euthyroid syndrome

Answer 22

abnormalities in thyroid fxn in ill patients without underlying thyroid or pituitary disease

Question 23

causes hypothyroidism

Answer 23

hashimoto
de quervain
reidel’s
cretinism

Question 24

hashimoto thyroiditis labs

Answer 24

antimicrosomal (antiperoxidase) antibodies

biopsy with lymphocytic infiltration of thyroid gland

assoc with autoimmune conditions like pernicious anemia

Question 25

myxedema coma

Answer 25

profound lethargy, coma, weakness, hypothermia, hypoventilation, hypoglycemia, hyponatremia

Question 26

thyroidectomy –> cramps, paresthesias

Answer 26

accidental removal of parathyroid glands –> hypocalcemia

Question 27

tx hypothyroidism

Answer 27

levothyroxine

Question 28

thyroid at back of tongue

Answer 28

thyroid fails to migrate appropriately to neck along thyroglossal duct

persistence of duct = cyst

Question 29

newborns + thyroid hormone

Answer 29

hypothyroidism = preventable cause of mental retardation

TH necessary for normal CNS development