Blood pressure, fludrocortisone dose and plasma renin activity in children with classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency followed from birth to 4 years of age.

[congenital adrenal hyperplasia]

Infants with congenital adrenal hyperplasia (CAH ) require higher doses of fludrocortisone (FC ) due to physiological mineralocorticoid resistance . The adequacy of mineralocorticoid replacement should be closely monitored to avoid hypertension .To evaluate blood pressure (BP ) in infants with CAH due to 21 -hydroxylase deficiency .Thirty -three patients (18 f /15 m ) diagnosed by newborn screening were followed until the age of 4 years . Mean start of HC and FC treatment was day 9 ·8 ± 9 ·2 postnatally . Mean daily HC dose ranged from 8 ·6 to 12 ·3 mg /m (2 ) /day .During the first year of life prevalence of systolic hypertension was up to 45 ·5 %. At 12 and at 18 months , BP was highest . Prevalence of systolic hypertension was up to 57 ·6 % at 18 months of age . After 24 months BP levels were lower and at 48 months prevalence of hypertension decreased to 15 ·2 %. Systolic and diastolic BP correlated significantly with the administered fludrocortisone dose (r = 0 ·3 , P = 0 ·005 ), but not with body mass index . Hypertensive children received significantly higher FC doses and had significantly lower plasma renin activity during the study period .High prevalence of transient , most likely FC induced hypertension was found in young children with classic CAH diagnosed by newborn screening . The changing mineralocorticoid sensitivity in infants is a risk factor for the development of hypertension in patients with CAH , who are treated with FC . Therefore suppressed plasma renin activity should be avoided to prevent arterial hypertension .