Congenital adrenal hyperplasia

1. Big picture

Congenital adrenal hyperplasia (CAH) is one of the most important pediatric endocrine emergencies because it can present as:

Newborn with vomiting + dehydration + shock + hyponatremia + hyperkalemia
→ salt-wasting CAH until proven otherwise

For the final exam, CAH is mainly about 21-hydroxylase deficiency.

The examiner wants you to know:

1. Why cortisol is low
2. Why androgens are high
3. Why some babies lose salt and collapse
4. Why girls may have ambiguous genitalia
5. How to recognize adrenal crisis
6. How to treat before the child dies

Core oral-exam sentence: “CAH is an autosomal recessive defect of adrenal steroid synthesis, most commonly 21-hydroxylase deficiency, causing cortisol deficiency, ACTH excess, adrenal hyperplasia, androgen excess, and sometimes aldosterone deficiency with salt-wasting adrenal crisis.”

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