Sodium chloride supplement at diagnosis and during infancy in children with salt-losing 21-hydroxylase deficiency

Area of Science:

• Pediatric Endocrinology
• Metabolic Disorders
• Genetics

Background:

• Congenital adrenal hyperplasia (CAH) is a group of genetic disorders affecting the adrenal glands.
• Salt-losing CAH, specifically due to 21-hydroxylase deficiency, presents a critical challenge in managing electrolyte balance in infants.
• Early diagnosis and appropriate management are crucial to prevent life-threatening complications.

Purpose of the Study:

• To quantify the sodium deficit at diagnosis in infants with salt-losing CAH.
• To determine the precise salt supplementation required in addition to hormone replacement therapy.
• To develop a practical method for calculating individual sodium supplement needs.

Main Methods:

• Studied eight infants (6 female, 2 male) diagnosed with salt-losing CAH.
• Measured sodium deficit at diagnosis (mmol and mmol/kg).
• Assessed the impact of varying sodium supplement levels on plasma sodium and plasma renin activity (PRA).

Main Results:

• Median sodium deficit at diagnosis was 34 mmol (10.5 mmol/kg).
• A mean daily sodium supplement of 2.2 mmol/kg was required, double the amount in standard feeds.
• This supplement level maintained normal plasma sodium and PRA in infants.

Conclusions:

• Salt-losing CAH necessitates lifelong mineralocorticoid treatment and significant additional salt supplementation during infancy.
• Underestimation of salt requirements can exacerbate hyponatremia, especially during infections, leading to hospitalization.
• A practical equation and management guidelines are provided to ensure adequate sodium balance.