A 32-year-old woman with systemic lupus erythematosus (SLE) presents with severe lupus nephritis (Class IV). She is started on high-dose prednisolone 1 mg/kg/day. After 3 weeks of therapy, she develops proximal muscle weakness, moon facies, and central obesity. Her serum potassium is 3.2 mEq/L (normal 3.5–5.0) and blood glucose is 180 mg/dL (fasting). Which of the following is the MOST appropriate next step in management?

Explanation

## Clinical Context This patient is experiencing **glucocorticoid excess syndrome** (Cushing-like features) and **mineralocorticoid side effects** (hypokalemia) from high-dose daily prednisolone. While the drug is necessary for lupus nephritis, the adverse effect burden demands mitigation. ## Key Pharmacological Principles **Key Point:** Prednisolone has both glucocorticoid and mineralocorticoid activity. At high doses (>20 mg/day), mineralocorticoid effects (sodium retention, potassium wasting, hypertension) become clinically significant. **High-Yield:** The three strategies to reduce corticosteroid toxicity are: 1. **Dose reduction** — taper as disease permits 2. **Alternate-day dosing** — reduces HPA suppression and side effects while maintaining efficacy for many conditions 3. **Steroid-sparing agents** — add immunosuppressants (mycophenolate mofetil, azathioprine, cyclophosphamide) to allow prednisolone tapering ## Management Strategy **Clinical Pearl:** In lupus nephritis, the goal is to use the **lowest effective dose** of prednisolone and transition to steroid-sparing agents as soon as induction therapy stabilizes the disease. Spironolactone (potassium-sparing diuretic) counteracts mineralocorticoid-induced hypokalemia and sodium retention. **Mnemonic — SAFER steroid use:** **S**teroid-sparing agents, **A**lternate-day dosing, **F**luctuate dose (taper), **E**lectrolyte monitoring, **R**educe to minimum effective dose. ### Why This Option Is Correct - **Spironolactone** blocks aldosterone receptors, preventing potassium wasting and sodium retention - **Alternate-day dosing** reduces cumulative HPA suppression and allows partial recovery of endogenous cortisol - **Mycophenolate mofetil** is a proven steroid-sparing agent in lupus nephritis, allowing prednisolone taper - This multimodal approach addresses both immediate electrolyte imbalance and long-term toxicity ## Why Other Options Fail | Option | Why Wrong | |--------|----------| | Continue same dose | Ignores life-threatening hypokalemia and iatrogenic Cushing syndrome; predisposes to cardiac arrhythmias, muscle breakdown, and osteoporosis | | Switch to dexamethasone | Dexamethasone is a **pure glucocorticoid** with minimal mineralocorticoid activity, but it is more potent (25 mg dexamethasone ≈ 100 mg prednisolone) and would worsen hyperglycemia; also no advantage over tapering prednisolone | | Discontinue prednisolone | Lupus nephritis requires induction immunosuppression; abrupt cessation risks disease flare and acute kidney injury | ## Monitoring & Follow-up - Repeat serum potassium, glucose, and blood pressure in 1–2 weeks - Taper prednisolone by 10 mg every 2–4 weeks as mycophenolate takes effect (usually 6–8 weeks) - Target maintenance dose: 5–10 mg/day prednisolone by 3–6 months [cite:Harrison 21e Ch 378]