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In this scenario, samples for 17(OH)P, cortisol and aldosterone, and plasma

renin activity should be sent, and therapy with hydrocortisone and intravenous

fl uids should be initiated empirically, pending the result of these investigations.

The distinguishing characteristics of various causes of salt-wasting based on the

results of biochemical investigations are summarized in the table given below.

Disorders 17(OH)P

Serum

cortisol

Plasma

aldosterone

Plasma renin

activity

Classical CAH (salt-wasting) Elevated Low Low Elevated

Congenital adrenal hypoplasia Low Low Low Elevated

Congenital hypoaldosteronism Normal Normal Low Elevated

Pseudohypoaldosteronism Normal Normal Elevated Elevated

16. How to treat a neonate with salt-wasting crisis due to CAH?

Prompt recognition and management is essential to prevent mortality asso-

ciated with salt-wasting crisis. The management of salt-wasting crisis

includes intravenous fluids preferably containing isotonic dextrose–saline

and intravenous hydrocortisone at doses of 100 mg/m^2 in divided doses.

Administration of dextrose with saline is preferred rather than saline, as

neonates with salt crisis are prone to hypoglycemia due to cortisol defi-

ciency as cortisol is also required for gluconeogenesis. Isotonic saline

promptly corrects intravascular volume depletion and helps in restoring

eukalemia. Once the child is hemodynamically stable and starts accepting

oral feed, therapy with oral hydrocortisone (10–15 mg/m^2 in divided doses)

and fludrocortisone (100 μg twice daily) can be initiated along with oral

salt supplementation (4–8 mmol/Kg). Newborns require higher doses of

fludrocortisone as they are aldosterone resistant.

17. What are the features of virilization of external genitalia in a 46,XX newborn?

The extent of virilization in a 46,XX newborn due to prenatal androgen expo-

sure may vary from Prader stage 1–5 depending on the time of exposure, sever-

ity of androgen excess, and sensitivity to androgens. Urogenital sinus

differentiation is complete by 12 th week of intrauterine life; hence, the androgen

exposure prior to 12 weeks results in labioscrotal fusion along with clitoro-

megaly, while exposure after 12 weeks results in isolated clitoromegaly. In

addition, the severity of androgen excess and sensitivity to androgens also

determine the extent of virilization (Fig. 10.4 ).

10 Congenital Adrenal Hyperplasia