Blood Pressure, Fludrocortisone Dose and Plasma Renin Activity in Infants with Classical Adrenal Hyperplasia due to 21-Hydroxylase Deficiency

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 26-40-Glucocorticoid Actions & Disease
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-37
Walter Bonfig*1 and Hans Peter Schwarz2
1University Children's Hospital, TU Munich, Munich, Germany, 2University of Bern, Lugnorre, Switzerland
Introduction: Newborns and infants with salt-wasting congenital adrenal hyperplasia (CAH)  require relatively high doses of fludrocortisone (FC) and may therefore be at risk for hypertension.

Objective: To evaluate blood pressure, FC doses and plasma renin activity (PRA) in infants with CAH due to 21-hydroxylase deficiency.

Patients & Methods: 33 patients (18f/15m), who were diagnosed with classical CAH by newborn-screening, were prospectively followed until the age of 4 years. Only two patients were diagnosed with simple virilizing CAH, 31 patients had salt-wasting CAH. All patients were initially treated with both hydrocortisone (HC) and FC. 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/m²/day over the study period.

Results: Mean birth weight and length were 0.39±0.8 SDS and 1.0±0.7 SDS, respectively. From three to 18 months of age, mean daily FC dose was approximately 0.1±0.05 mg. At 24 months mean daily FC dose could be decreased to 0.05±0.02 mg. Initially, at three months of age, mean PRA was elevated (PRA 16.6±26.6 ng/ml/h) and normalized by the age of six months (PRA 5.3±13.1 ng/ml/h). The lowest mean PRA was measured at 24 months of age (PRA 1.8±2.7 ng/ml/h). Mean blood pressure was normal at three and six months of age (RR sytolic 100±25 mmHg and 105±21 mmHg, RR diastolic 66±19 mmHg and 68±16 mmHg). At twelve and at 18 months of age mean RR was highest (RR sytolic 117±20 mmHg and 118±28 mmHg, RR diastolic 77±21 mmHg and 81±26 mmHg). At 36 and at 48 months RR was back to the mean initial RR levels (RR systolic 100±15 mmHg and 99±17 mmHg, RR diastolic 61±12 mmHg and 63±12 mmHg). BMI-SDS was elevated at three months of age (mean BMI-SDS +0.55±1.1) and was below average between six and 24 months of age (mean BMI-SDS at six months –0.3±1.1, at twelve months –0.4±1.3, at 18 months –0.3±0.9 and at 24 months –0.2±0.9). At 36 months of age BMI-SDS was around average (0.1±0.9 SDS) and increased further at 48 months (0.4±0.77 SDS).

Conclusion: Elevated RR was found at 12 and at 18 months of age in children with classical CAH under HC and FC treatment. Between 18 and 24 months of age mean FC dose could be decreased from 0.1 mg/day to 0.05 mg/day. 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 measurement of PRA or renin and blood pressure at regular intervals are essential.

Nothing to Disclose: WB, HPS

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