Monitor Mineralocorticoid Replacement via Clinical Assessment and Electrolytes
STEP 1 — Gather Information
Collect history of salt craving, light‑headedness or postural dizziness, peripheral edema; measure supine and standing blood pressure; obtain serum sodium and potassium levels.
STEP 2 — Rule In / Rule Out
If any of the following are present: salt craving, postural hypotension, edema, serum Na⁺ <135 mmol/L, or serum K⁺ >5.0 mmol/L → Rule In (inadequate mineralocorticoid replacement); otherwise → Rule Out (adequate replacement).
STEP 3 — Classify or Stratify
Classify the patient as:
- Under‑replacement: signs/symptoms of deficiency (salt craving, postural hypotension, edema) with low/normal Na⁺ or high K⁺.
- Adequate: absence of deficiency signs and electrolytes within normal range.
- Over‑replacement: hypertension, supine edema, hypokalemia (K⁺ <3.5 mmol/L) or unexplained weight gain.
STEP 4 — Decide
- Under‑replacement: consider increasing fludrocortisone dose by 50–100 µg daily.
- Over‑replacement: consider decreasing fludrocortisone dose by 50–100 µg daily and evaluate for hypertension causes.
- Adequate: maintain current dose and reassess at next routine visit.
Clinical Guardrails / Mimics / Pitfalls
Do not rely solely on electrolytes; avoid using diuretics to treat hypertension from over‑replacement; do not advise salt restriction; be aware that licorice, grapefruit juice, or phenytoin can potentiate fludrocortisone effect; avoid dose changes based only on plasma renin without clinical correlation.
Concrete Clinical Example
A 48‑year‑old man on fludrocortisone 100 µg daily reports new salt craving and mild light‑headedness on standing. Supine BP 118/72 mmHg, standing BP 96/60 mmHg; serum Na⁺ 132 mmol/L, K⁺ 5.3 mmol/L. Findings indicate under‑replacement; fludrocortisone is increased to 150 µg daily with follow‑up in 4 weeks.
Source: Diagnosis and Treatment of Primary Adrenal Insufficiency: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2016, doi:10.1210/jc.2015-1710