Abstract:
Classic congenital adrenal hyperplasia (CAH) due
to 21-hydroxylase deficiency is rare, occurring
approximately once in every 15 000 live births.1
At birth it is often suspected in girls because of
ambiguous genitalia, whereas boys have normal
genitalia. The salt-losing type of CAH presents
with adrenal crisis a few weeks after birth, while
the simple type manifests virilisation and rapid
growth years later. The diagnosis is confirmed by
an elevated plasma 17-hydroxyprogesterone (17-
OHP) level. Additional features in the salt-losing
variety are hyponatraemia, hyperkalaemia, metabolic
acidosis and an elevated plasma renin level. The
gluco- and mineralocorticoid insufficiency is corrected
by providing hydrocortisone and fludrocortisone,
respectively. It may be necessary to add sodium
chloride to infant feeds. Treatment is lifelong. If
compliance is poor, excess androgen production,
accelerated growth, secondary central precocious
puberty and, in boys, adrenal rest tumours can occur,
as in the following case.
