Treatment of congenital adrenal hyperplasia replaces the cortisol and aldosterone the adrenal gland cannot make and suppresses the excess androgen drive, while avoiding the harm of giving too much glucocorticoid.
Glucocorticoid and mineralocorticoid replacement
In growing children, classic CAH is treated with hydrocortisone, typically 10-15 mg per square meter of body surface area per day divided into three doses. Long-acting potent glucocorticoids such as dexamethasone are avoided during growth because they suppress linear growth; once growth is complete, a longer-acting preparation can be used instead.
Infants and young children with the salt-wasting form also receive fludrocortisone (0.05-0.2 mg per day) and sodium chloride supplements (1-2 g per day), because breast milk and ordinary infant feeding do not supply the sodium these patients lose. Blood pressure is monitored closely in infants on mineralocorticoid, since the immature renal tubule responds variably to the dose.
Monitoring
The dose is adjusted to keep androgens under control without producing glucocorticoid excess. 17-hydroxyprogesterone and androstenedione are measured before the morning dose, when they peak, and the aim is to keep 17-hydroxyprogesterone within a target range rather than to normalize it completely, because driving it fully down requires over-treatment and produces iatrogenic Cushing syndrome, the state of glucocorticoid excess caused by treatment. Monitoring therefore looks in both directions at once — for signs of cortisol excess and for signs that androgen production is not adequately suppressed.
Adrenal crisis
Patients with classic CAH are at risk of adrenal crisis and need the same precautions as any patient on glucocorticoid replacement: stress-dose instructions (raising the glucocorticoid dose during illness or stress), an emergency card, and injectable hydrocortisone for use when oral treatment cannot be taken.
Virilized genitalia and prenatal treatment
Virilized external genitalia in females may be treated surgically, but the timing and the operation carry uncertainty, so the decision is shared between the family and a multidisciplinary team rather than made routinely at birth. Prenatal dexamethasone to prevent virilization is not recommended outside research settings.
Non-classical disease
Unlike the classic forms, non-classical CAH is milder and does not always need treatment. Glucocorticoid therapy is offered to patients with symptoms of androgen excess — such as hirsutism, irregular menses or infertility — and is withheld from asymptomatic individuals, because the long-term risks of glucocorticoid therapy outweigh any benefit when there is no clinical problem to treat.