What is the most appropriate next step for a baby with congenital adrenal hyperplasia (CAH) presenting with hypoglycemia, hyponatremia, and hyperkalemia?

Management of Acute Adrenal Crisis in Congenital Adrenal Hyperplasia

For a baby with congenital adrenal hyperplasia presenting with hypoglycemia, hyponatremia, and hyperkalemia, the most appropriate next step is IV hydrocortisone 100 mg immediately followed by isotonic normal saline infusion. 1

Immediate Emergency Treatment

This presentation represents an acute adrenal crisis requiring immediate intervention without delay for further diagnostic procedures. 1

Initial resuscitation consists of:

• Rapid intravenous administration of hydrocortisone 100 mg bolus to saturate mineralocorticoid receptors and provide immediate glucocorticoid replacement 1
• Isotonic saline (0.9% NaCl) 1 liter over the first hour (or age-appropriate volume for infants: approximately 20 mL/kg bolus) to correct hypovolemia and hyponatremia 1
• Continue isotonic saline infusion at a slower rate for the following 24-48 hours with frequent hemodynamic monitoring 1

The high-dose IV hydrocortisone serves a dual purpose: it provides glucocorticoid replacement for hypoglycemia and also saturates type 2 hydroxysteroid dehydrogenase to achieve mineralocorticoid effects, addressing the hyperkalemia and hyponatremia. 1

Why Not the Other Options

Oral hydrocortisone and fludrocortisone is inappropriate because:

• A baby in adrenal crisis with hypoglycemia, hyponatremia, and hyperkalemia is critically ill and requires immediate IV therapy, not oral medication 1
• Oral absorption is unreliable in an acutely ill infant who may have vomiting or altered consciousness 1
• The crisis requires immediate high-dose parenteral glucocorticoids (100 mg hydrocortisone) that cannot be achieved orally 1

Sodium bicarbonate and insulin is inappropriate because:

• This treats hyperkalemia symptomatically but does not address the underlying adrenal insufficiency causing the electrolyte derangements 1
• It fails to provide the essential glucocorticoid replacement needed for hypoglycemia 1
• It does not correct the volume depletion and sodium deficit 1

Subsequent Management After Stabilization

Once the infant is stabilized (typically 24-48 hours):

• Taper parenteral hydrocortisone over 1-3 days to oral hydrocortisone 6-10 mg/m² body surface area daily in divided doses 1, 2
• Initiate fludrocortisone 50-200 µg daily as a single morning dose for mineralocorticoid replacement 1, 3, 2
• First oral hydrocortisone dose should be given immediately upon waking, last dose at least 6 hours before bedtime 1, 4

Monitoring During Acute Phase

• Serum electrolytes (sodium, potassium) every 4-6 hours until normalized 1
• Blood glucose monitoring to ensure hypoglycemia resolves 1
• Hemodynamic monitoring with frequent blood pressure checks 1
• Evaluate for precipitating causes such as infection 1

Common Pitfalls to Avoid

• Never delay treatment for diagnostic procedures when adrenal crisis is suspected—draw blood for cortisol and ACTH, then treat immediately 1, 5
• Do not use oral medications in an acute crisis setting 1
• Do not treat hyperkalemia in isolation without addressing the underlying adrenal insufficiency 1
• Avoid rapid correction of hyponatremia (>10-15 mmol/L per 24 hours) to prevent cerebral edema 1

Long-Term Considerations

After acute stabilization, all infants with classical CAH require:

• Lifelong glucocorticoid and mineralocorticoid replacement 2, 6
• Regular monitoring of growth, blood pressure, and electrolytes 1, 3
• Patient/family education about stress dosing during illness 1, 4
• Medical alert identification 1, 4

The key distinction is that acute adrenal crisis requires immediate IV therapy with high-dose hydrocortisone and volume resuscitation, while oral maintenance therapy with both hydrocortisone and fludrocortisone is only appropriate after stabilization. 1