The progression of salt wasting and the body weight change during the first two weeks of life in classical 21-hydroxylase deficiency patients.

BACKGROUND One of the major purposes of newborn screening for 21-hydroxylase deficiency (21OHD) is preventing life-threatening adrenal crisis. However, the details of adrenal crisis in newborns are not precisely documented. AIM We aimed to clarify the clinical details of salt-wasting in newborn 21OHD patients. METHODS Based on the follow-up survey of the screening in Tokyo from 1989 to 2017, we retrospectively analysed the conditions of classical 21OHD neonates before the initiation of therapy. RESULTS One hundred classical 21OHD patients (55 male, 45 female) were analysed. The age at the first hospital visit was 0-20 days with sex difference (male: 9.0 ± 3.5 days; female: 6.2 ± 3.9 days). Thirty-seven (37.4%) patients exhibited severe salt-wasting (SSW), that is, Na   7 mEq/L or Na/K ratio   7 mEq/L and Na/K < 20 was approximately coincided, 11.1, 12.3 and 11.2 days, respectively. All SSW patients exhibited decreased body weight from birth in their second week of life. CONCLUSION Our data revealed that the risk of developing SSW increases during the second week of life without a threshold, and for preventing SSW, early intervention, ideally during first week of life, is desirable. An increased body weight in the second week of life indicates the absence of SSW.