Reinstitution of mineralocorticoid therapy in congenital adrenal hyperplasia. Effects on control and growth.

The results of reintroduction of mineralocorticoid substitution therapy (9-alpha-fluorohydrocortisone) in five children with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency are described. All children had shown a salt-losing syndrome in infancy, but were off mineralocorticoids during several years; at the start of this study they all had elevated plasma renin activity (PRA). Four of them had increased and fluctuating pregnanetriol excretion during the year preceding reintroduction of mineralocorticoids, indicating poor control despite substantial substitution with hydrocortisone: 26 +/- 1.9 mg/m2/day (mean +/- S.E.M.). Reintroduction of mineralocorticoid therapy at ages 5.0-9.4 years resulted in a marked improvement of control, significant reduction in hydrocortisone requirements (to 17.6 +/- 1.4 mg/m2/day) and improvement in linear growth. The data suggest that, in all children with CAH and elevated PRA, continuation throughout childhood of mineralocorticoid therapy in addition to glucocorticoid therapy is necessary for optimal control and linear growth.