Prescribe Fludrocortisone for Children with Aldosterone Deficiency; Provide Sodium Chloride Supplements for Infants
STEP 1 — Gather Information
Confirm primary adrenal insufficiency (PAI) diagnosis; assess aldosterone deficiency via plasma renin (elevated) and aldosterone (low), plus clinical signs: salt craving, hyponatremia, hyperkalemia. Determine patient age (infant <12 months vs child ≥1 year). Record weight and blood pressure.
STEP 2 — Rule In / Rule Out
Is aldosterone deficiency confirmed (low aldosterone with high renin or clinical salt-wasting)?
- Yes → proceed to STEP 3.
- No → do not initiate fludrocortisone or sodium chloride supplement; reassess for other causes.
STEP 3 — Classify or Stratify
Stratify by age:
- Infant (<12 months)
- Child (≥1 year)
STEP 4 — Decide
- Infant: prescribe sodium chloride supplement 1–2 g/day divided into multiple feeds; monitor weight, serum electrolytes, and blood pressure.
- Child: prescribe fludrocortisone 100 µg once daily (preferably morning); monitor for hypertension, edema, and electrolyte balance.
Clinical Guardrails / Mimics / Pitfalls
Avoid salt restriction in infants; excessive fludrocortisone may cause hypertension, edema, and suppressed renin. Do not use fludrocortisone alone in infants without sodium chloride supplementation due to mineralocorticoid resistance. Monitor for signs of over-replacement (hypertension, hypokalemia) and under-replacement (persistent salt craving, poor growth, hyponatremia). Do not rely solely on fludrocortisone dose adjustment for blood pressure control; consider antihypertensives if needed.
Clinical Clinical Example
A 7-month-old infant with known PAI presents with poor weight gain, frequent salt craving, serum sodium 128 mmol/L, potassium 5.8 mmol/L, renin markedly elevated, aldosterone low. Diagnosed with aldosterone deficiency. Prescribed sodium chloride supplement 1.5 g/day divided into breastfeeds. After one week, weight improved, sodium normalized to 135 mmol/L, potassium 4.2 mmol/L. Continued supplement with monthly electrolyte checks.
Source: Diagnosis and Treatment of Primary Adrenal Insufficiency: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2016, DOI:10.1210/jc.2015-1710
TODO: consider adding scripts/calc.py for the enda-pediatric-fludrocortisone-infants-nacl calculator