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Adrenal Hypoplasia Congenita — RACP Paediatrics MCQ

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HardEndocrinologyAdrenal Hypoplasia CongenitaRACP Paediatrics

A 3-week-old infant presents with poor feeding, lethargy, and hypoglycaemia. Investigations show low cortisol, low aldosterone, elevated ACTH, elevated renin, and hyperkalaemia with hyponatraemia. 17-OHP is normal. What is the most likely diagnosis?

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Correct answer: B — Primary adrenal insufficiency (Addison disease, likely adrenal hypoplasia congenita)

Low cortisol AND low aldosterone with elevated ACTH and renin, normal 17-OHP, in a male infant suggests X-linked adrenal hypoplasia congenita (DAX1/NR0B1 mutation) or congenital adrenal hypoplasia. 21-hydroxylase deficiency would show elevated 17-OHP. Treatment is glucocorticoid and mineralocorticoid replacement.

Reference: RCH Melbourne – 2024 – Clinical Practice Guidelines: Adrenal Insufficiency