Session: FP37-Clinical Pediatric Endocrinology
Room 102 (Moscone Center)
Poster Board MON-599
Methods:Plasma catecholamines were measured by high performance liquid chromatography in 6 newborns with classical CAH and in 9 newborn controls with congenital hypothyroidism. Baseline measurements were collected at the time of diagnosis (visit 1) for both groups, and 3-5 weeks later in the control group (visit 2) after infants were rendered euthyroid with thyroxine replacement.
Results: Both study groups consisted of full-term, female infants, with no significant difference in age (CAH 4.2 ± 1.5 days for 5 CAH babies, one additional subject was 61 days old; controls 7.7 ± 3.4 days), birth weight, birth length, weight, length, or vital signs at study entry. CAH subjects had ambiguous genitalia (67% Prader 4, 33% Prader 3). Controls were not stressed at visits 1 or 2 (cortisol 6.15 ± 4.19 and 3.28 ± 2.75 μg/dL, p = 0.4). Basal plasma epinephrine (epi) levels were significantly lower in the CAH group compared to controls (83.8 ± 12.3 vs. 119.8 ± 38.5 pg/mL, p = 0.04). Basal plasma norepinephrine (norepi) levels did not differ between the CAH and control groups (1243 ± 667.8 vs. 952.8 ± 221.8 pg/mL, p = 0.27). In addition, compared to older children (mean age 12.4 ± 4 years) previously studied in our institution, basal plasma epi and norepi levels were significantly higher in the newborns (older children: epi 32 ± 25.47 pg/mL, norepi 327 ± 111.45 pg/mL; p < 0.001 for both). There was a negative, although not significant, correlation between epi and newborn screen 17-hydroxyprogesterone (17-OHP) (r = -0.6, p = 0.2). There was no significant change in plasma epi from visit 1 to 2 in the control group (p = 0.65), thus, accounting for a possible confounding effect of hypothyroidism on catecholamine production.
Discussion: Newborns with classical CAH have decreased levels of plasma epi compared to controls, indicating that adrenomedullary hypofunction may be present at birth. Conversion of norepi to epi is mediated by intra-adrenal glucocorticoids; thus, decreased levels of plasma epi in newborns with CAH may be due to adrenocortical dysfunction during fetal development. In addition, the lower catecholamine levels in older children may imply a further decrease in adrenomedullary function over time. Larger prospective longitudinal studies of adrenomedullary dysfunction in patients with CAH are warranted.
Nothing to Disclose: AR, BB, SH, CL, AHP, MEG, MSK
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