next best step would be pelvic ultrasound, followed by karyotype if needed

A.

 

D 17-OH-progesterone level

 

The answer is C

CAH caused by the 21-hydroxylase defect is the most common cause of distinct virilization of the female newborn. Its incidence is 1 in 5,000 births and accounts for 95% of all cases of CAH. The chromosomes, gonads, and internal genitalia are female but the external genitalia are virilized to varying degrees due to excess production of fetal androgens during development. Although

it is important to confirm the diagnosis with a serum17-OH-progesterone level, the most crucial first step is to evaluate serum electrolytes because salt wasting may be present and can be fatal in the neonatal period. Repletion of necessary electrolytes is critical as is suppression of the adrenal gland.

A karyotype should be obtained later to rule out other causes of ambiguous genitalia, such as hermaphroditism and mixed gonadal dysgenesis. You should not assign a gender until you have all of the information.

 

........... the most crucial first step is to evaluate serum electrolytes because salt wasting may be present and can be fatal in the neonatal period....................

I left that part for the Pediatrician. I was there for the expert opinion )

 

Real CK exam like Q
thanks Gyrus

 

its either A or D. however D is more appropriate. as the enzyme might have led to ambiguous genitalia. however we can confirm with karyotype.