Congenital adrenal hyperplasia: epidemiology, management and practical drug treatment.

Congenital adrenal hyperplasia (CAH) owing to 21-hydroxylase deficiency is a common disorder, and is characterised by a defect in cortisol biosynthesis with or without a defect in aldosterone synthesis and androgen excess. The classic form, also known as the severe form, occurs in 1:15,000 births worldwide, while the nonclassic or mild form occurs in approximately 1:1,000 births worldwide and is much more common (up to 1:20) in certain ethnic groups. In classic 21-hydroxylase deficiency, glucocorticoids are given in doses sufficient to suppress adrenal androgen secretion, and mineralocorticoids are given to normalise electrolytes and plasma renin activity. The management of CAH may be complicated by iatrogenic Cushing's syndrome, inadequately treated hyperandrogenism, or both. Prenatal treatment may decrease virilisation of the affected female foetus, but the efficacy and safety of treating CAH prenatally remains to be fully defined. Close clinical monitoring of growth and development is essential to optimise treatment outcome. New treatment approaches are currently under investigation in the most severely affected patients, while nonclassic CAH does not always require treatment.