Decreased adrenomedullary function in infants with classical congenital adrenal hyperplasia.

[congenital adrenal hyperplasia]

Classical congenital adrenal hyperplasia (CAH ) due to 21 -hydroxylase deficiency can cause life-threatening adrenal crises as well as severe hypoglycemia , especially in very young children . Studies of CAH patients 4 years old or older have found abnormal morphology and function of the adrenal medulla and lower levels of epinephrine and glucose in response to stress than in controls . However , it is unknown whether such adrenomedullary abnormalities develop in utero and /or exist during the clinically high -risk period of infancy and early childhood .The objective of the study was to characterize adrenomedullary function in infants with CAH by comparing their catecholamine levels with controls . Design /Settings : This was a prospective cross-sectional study in a pediatric tertiary care center .Plasma epinephrine and norepinephrine levels were measured by HPLC .Infants with CAH (n = 9 , aged 9 .6 ± 11 .4 d ) had significantly lower epinephrine levels than controls [n = 12 , aged 7 .2 ± 3 .2 d : median 84 [(25 th ; 75 th ) 51 ; 87 ] vs 114 .5 (86 ; 175 .8 ) pg /mL , respectively (P = .02 )]. Norepinephrine to epinephrine ratios were also significantly higher in CAH patients than controls (P = .01 ). The control infants had primary hypothyroidism , but pre- and posttreatment analyses revealed no confounding effects on catecholamine levels .This study demonstrates for the first time that infants with classical CAH due to 21 -hydroxylase deficiency have significantly lower plasma epinephrine levels than controls , indicating that impaired adrenomedullary function may occur during fetal development and be present from birth . A longitudinal study of adrenomedullary function in CAH patients from infancy through early childhood is warranted .