Prevention of fetal virilization in congenital adrenal hyperplasia Flashcards Preview

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Flashcards in Prevention of fetal virilization in congenital adrenal hyperplasia Deck (3)
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1

A 28-year-old woman, gravida 2, para 1, comes to your office at 5 weeks of gestation. Her previous pregnancy resulted in a severely virilized female infant with 21-hydroxylase deficiency. The best time to initiate treatment with dexamethasone to prevent virilization of a female fetus in the current pregnancy is:

(A) immediately
(B) after 12 weeks
(C) at birth
(D) only after karyotype is confirmed to be XX
(E) only after karyotype is confirmed to be XY

(A) immediately

2

What is the most common cause of congenital adrenal hyperplasia, and what are the clinical characteristics?

Cause: autosomal recessive 21-hydroxylase (CYP21) deficiency in 90% of cases --> can't make cortisol --> make more adrenocorticotropin hormones --> virilization

Characteristics: urogenital sinus, labial fusion, scrotalization of labia majora, clitoromegaly, penis enlargement, precocious adrenarche, bone age advancement, rapid growth, acne, hirsutism, menstrual abnormalities, infertility

3

How do you prevent virilization in affected female fetuses?

Start dexamethasone as soon as possible - only stop when sex is confirmed 46 XY

Need to treat because masculinization of external genitalia starts at 6-7w (8-9w after most recent menstrual period); need to start at 3-6w to suppress fetal pituitary adrenocorticotropic hormone levels