skip to main content

Classic congenital adrenal hyperplasia — SCE Endocrinology MCQ

Instant feedback + full explanation. One question, done properly.

HardReproductive EndocrinologyClassic congenital adrenal hyperplasiaSCE Endocrinology

A newborn has ambiguous genitalia, vomiting and weight loss at day 9. Sodium is 121 mmol/L, potassium is 6.8 mmol/L and glucose is 2.4 mmol/L. 17-hydroxyprogesterone is markedly elevated. What is the most likely biochemical finding?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — High ACTH with low cortisol and low aldosterone

Salt-wasting 21-hydroxylase deficiency causes cortisol and aldosterone deficiency with ACTH-driven adrenal precursor accumulation. Low renin with high aldosterone would suggest mineralocorticoid excess, not salt wasting. The pearl is that CAH is both a DSD and an adrenal emergency.

Reference: Endocrine Society congenital adrenal hyperplasia guideline