Evaluation of Ambiguous Genitalia Flashcards
What is the first thing you should do when evaluating a newborn for ambiguous genitalia?
Monitor Na, K, vitals, fluid balance, and daily weights
After evaluating fluid and electrolytes what should be the next step when working up ambiguous genitalia?
Palpate the gonads
What is the next step in working up ambiguous genitalia if the gonads are palpable?
Get Karyotype and pelvic ultrasound to see if mullerian structures are present or absent.
What is the diagnosis if mullerian structures are present with palpable gonads?
Mixed gonadal dysgenesis
True pseudohermaphrodite
Persistent mullerian ducts.
What is the next step if Mullerian structures are absent on pelvic ultrasound?
HCG stimulation test (give HCG 2000 IU IM Q24h x 4 days and measure T, DHT, and androstenedione before and after administration.) (T/DHT ratio > 40 is elevated,
What is the diagnosis if T/DHT ratio is elevated at > 40 after HCG?
5-alpha-reductase deficiency
Can confirm by measuring 5-alpha-reductase activity in genital skin cultures
What is the next step if T/DHT ratio is normal at
Measure plasma testosterone and look for an increase of > 2ng/ml after HCG.
What is the diagnosis if the Plasma testosterone rises by more than 2ng/ml?
Androgen insensitivity syndrome
What is the next step if the plasma testosterone does not increase by more than 2ng/ml?
Obtain serum levels of
- dihydroepiandrosterone
- Deoxycorticosterone
- 17-hydroxypregnenalone
- 17-hydroxyprogesterone
looking for problems with steroid synthesis
What is the next step if the gonads are not palpable?
Obtain within 24 hours of birth
- Serum Na and K
- Serum ACTH
- Serum 17-alpha-hydroxyprogesterone
What is the next step if the patient has normal 17 alpha-OHP and normal ACTH?
Karyotype and MIF
What is the next step in the workup of ambiguous genitalia if MIF is > 0?
Karyotype and pelvic ultrasound
What is the diagnosis if MIF is 0 and karyotype is XX?
Virulized by maternal androgens.
What is the diagnosis if 17-alpha-OHP is normal and ACTH is elevated?
3beta-hyroxysteroid dehydrogenase deficiency or 11-hydroxylase deficiency (CAH)
What is the diagnosis if 17-alpha-OHP is elevated and ACTH is elevated?
21-hydroxylase deficiency (CAH)
