Electronic supplementary material
What is Known:
• In neonates, hyponatremia may be multifactorial, making it difficult to treat.
• Newborns display partial resistance to aldosterone, and preterms have a defect in aldosterone secretion.
What is New:
• Four percent of hospitalized neonates had hyponatremia, 86% hospital-acquired. Hyponatremia was due to a transient or constitutional defect of the mineralocorticoid pathway in 26/86 patients (30%) which is higher than expected.
• We propose a tree diagram for improving the management of hyponatremia in neonates.