020415 hypothyroidism peds

Question 1

oxidation of iodine

Answer 1

converting I- to I2

Question 2

what is regulated in terms of thyroid hormone levels?

Answer 2

the FREE, UNBOUND thyroid hormone

NOT the TBG bound thyroid hormone

Question 3

causes of congenital hypothyroidism

Answer 3

absent thyroid or small ectopic thyroid

• -dysgenesis (MOST COMMON)
• -2% familial

dyshormonogenesis (gland is formed but doesn’t fxn normally)

iodine deficiency (most common worldwide)

central hypothyroidism

transient (late maturation, antibodies from mother with autoimmune thyroiditis, drugs)

Question 4

presentaiton of congenital hypothyroidism

Answer 4

most infants are asymptomatic at birth b/c mother’s thyroid hormones can help baby (therefore, there’s a need to screen)

if untreated: feeding problems, macroglossia, umbilical hernia, large fontanels, prolonged jaundice, lack of normal brain development

Question 5

newborn screening for hypothyroidism consists of

Answer 5

measuring T4 and/or TSH (advantage of measuring T4 is that it picks up central hypothyroidism, whereas just TSH may miss central)

note: TSH may be high in a normal newborn spike

Question 6

tx of congenital hypothyroidism

Answer 6

levothyroxine (T4)

Question 7

when is compliance with tx of levo critical for congenital hypothyroidism

Answer 7

first 3 years of life, b/c this period is important for brain development (hypothyr after age 3 doesn’t affect brain development)

Question 8

why is it essential to screen babies at birth for hypothyroidism?

Answer 8

because it may not have obvious symptoms and when symptoms become obvious enough, brain damage may have already occurred