Congenital adrenal hyperplasia (CAH) is the most common cause of ambiguous genitalia.
a simple case introducing clincial presentation and calling for a differential diagnosis. To get students thinking.
CAH is an autosomal-dominant condition leading to partial or total enzyme defect.
In over 95% of cases, 21-hydroxylase deficiency leads to decreased cortisol and aldosterone, leading to androgen overproduction.
Cortisol deficiency increases ACTH production, leading to adrenal hyperplasia.
Different types include:
Salt-wasting accounts for over half of cases. It leads to low [Na], high [K], low [Cl], low glucose, and high ACTH.
It is a medical emergency, as infants can die of dehydration and shock at 2-4 weeks of age.
Treat with fluid and electrolytes, restore glucose, and start lifetime regimen of hydrocortisone.
Clinical presentation depends on specific deficieincy.
Salt-wasting 21-hydroxylase deficiency can lead to hyperpigmentation of genitals and areola.
Increased ACTH leads to increased:
Advanced bone age results.
Stress dosing of cortisol
Case #2 - a small story wrapping it all up and asking about esp management.