020415 hypothyroidism in adult Flashcards Preview

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Flashcards in 020415 hypothyroidism in adult Deck (10):
1

most common hypothyroidism

primary hypothyroidism (Hashimoto's thyroiditis)

2

chronic lymphocytic thyroiditis

Hashimoto's thyroiditis

3

mechanism of chronic lymphocytic thyroiditis

sensitization of host's own lymphocytes to various thyroidal antigens (thyroblogulin, thyroid peroxidase, TSH receptor)

cytokine release and inflam ultimately result in glandular destruction

4

differential diagnosis of hypothyroidism that's primary

chronic lymphocytic thyroiditis (Hashimoto's)
thyroidectomy
reversible autoimmune thyroiditis (silent and postpartum thyroiditis)
thyroid irradiation
infilatrative and infectious dis
thyroid dysgenesis (no formation of thyroid)
iodine deficiency
iodine excess (Wolff Chaikoff effect)--thyroid shuts down
drugs

5

differential diagnosis of secondary/tertiary (central) hypothyroidism

tumors
trauma
infiltrative diseases (sarcoidosis, hemochromatosis)
drugs
inactivating mutations in genes that code for proteins involved in hypothalamic-pituitary-thyroid axis

6

clinical features of hypothyroidism

losing outer 1/3 of eyebrow
periorbital puffiness
thickening of skin
myxedema
affects just about everything

in severe, there's myxedema (bulging of eyes and pretibial swelling)

7

how to diagnose hypothyroidism?

do first: serum TSH (much more sensitive than thyroid hormone)

if TSH is abnormal, or if there is a high clinical suspicion for a central disease process, free T4 is ordered to further characterize the thyroid condition. thyroid antibodies often tested.

8

in secondary/tertiary hypothyroidism, what are the levels of TSH and free T4, T3?

TSH: low or normal
free T4, T3: low

9

half life of levothyroxine vs liothyronine (T3)

T4 has half life of 7 days
T3: 1 day

10

myxedema coma

severe hypothyroidism
multiorgan dysfxn, serious hypothermia, hypoventilation, hypotension, and CNS signs