In a melanoma patient who was treated with checkpoint inhibitor therapy and a recent prednisone taper that was abruptly stopped, now presenting with symptoms of adrenal insufficiency (drunkenness, profound fatigue, balance disturbance), mild hyponatremia, and a low random cortisol level, how should the adrenal insufficiency be managed?

Immediate Glucocorticoid Replacement for Glucocorticoid-Induced Adrenal Insufficiency

This patient has glucocorticoid-induced secondary adrenal insufficiency and requires immediate glucocorticoid replacement therapy with hydrocortisone 15-25 mg daily (or prednisone 5 mg daily equivalent), NOT stress-dose steroids, as the symptoms and low cortisol (2.7 mcg/dL at 0953) confirm adrenal crisis risk following abrupt cessation of a 20-day supraphysiologic prednisone taper.

Clinical Reasoning

This patient received prednisone 10-50 mg daily for 20 days (well exceeding the 3-4 week threshold at supraphysiologic doses that suppresses the HPA axis), then stopped abruptly 4 days ago 1. The random morning cortisol of 2.7 mcg/dL is severely low (normal AM cortisol should be >10 mcg/dL), confirming adrenal insufficiency. The symptoms—"drunkenness," profound fatigue, balance issues—combined with mild hyponatremia (Na 132) are classic for adrenal insufficiency 2.

The FDA label explicitly warns that "drug-induced secondary adrenocortical insufficiency may be minimized by gradual reduction of dosage" and that "this type of relative insufficiency may persist for up to 12 months after discontinuation of therapy" 2. The abrupt stop after only 20 days of tapering (ending at 10 mg, still supraphysiologic) caused symptomatic HPA axis suppression.

Immediate Management Algorithm

1. Start Physiologic Glucocorticoid Replacement NOW

• Hydrocortisone 15-20 mg PO daily (divided: 10 mg upon waking, 5 mg early afternoon) 1
  • OR Prednisone 5 mg PO daily (single morning dose) if hydrocortisone unavailable
• Do NOT use stress-dose steroids unless the patient develops hypotension, shock, or vomiting (none present here)
• The 2024 ESE/Endocrine Society guideline defines physiologic replacement as 15-25 mg hydrocortisone or 4-6 mg prednisone daily 1

2. Avoid Prednisone if Possible in This Melanoma Patient

• Recent 2025 data shows prednisone use in melanoma patients with secondary adrenal insufficiency is associated with decreased survival (HR 2.31,95% CI 1.14-4.46) compared to hydrocortisone 3
• Hydrocortisone is the preferred agent for replacement in cancer patients with checkpoint inhibitor-related or glucocorticoid-induced adrenal insufficiency 3
• If only prednisone is available, use 5 mg daily, but transition to hydrocortisone as soon as feasible

3. Monitor and Educate

• Recheck basic metabolic panel in 3-5 days (expect sodium to normalize with glucocorticoid replacement)
• The elevated transaminases (AST 122, ALT 154) likely reflect resolving checkpoint inhibitor hepatitis or liver metastases, not acute adrenal crisis
• Patient education on stress dosing: Double or triple the glucocorticoid dose during illness, fever, or procedures 4, 2
• Provide emergency injectable hydrocortisone (100 mg IM) for adrenal crisis prevention 4

4. Duration of Replacement Therapy

• HPA axis suppression can persist up to 12 months after stopping supraphysiologic glucocorticoids 1, 2
• Reassess adrenal function in 8-12 weeks with an 8 AM cortisol (off glucocorticoids for 24 hours) or ACTH stimulation test 1
• If 8 AM cortisol >10-15 mcg/dL, consider tapering replacement; if <10 mcg/dL, continue replacement and retest in 2-3 months

Critical Pitfalls to Avoid

1. Do NOT restart high-dose prednisone (e.g., 40-50 mg) thinking this is a "flare" of pneumonitis—the pneumonitis was treated, and the current symptoms are purely adrenal insufficiency
2. Do NOT delay glucocorticoid replacement to "confirm" with ACTH stimulation testing—the random cortisol of 2.7 mcg/dL is diagnostic, and the patient is symptomatic 1, 5, 6
3. Do NOT attribute symptoms to brain metastases without neuroimaging—adrenal insufficiency causes neurologic symptoms (confusion, ataxia) that resolve with replacement 7, 8
4. Do NOT use dexamethasone for chronic replacement—it lacks mineralocorticoid activity and has a longer half-life, making dose adjustments difficult 1

Checkpoint Inhibitor Context

While this patient's adrenal insufficiency is glucocorticoid-induced (from prednisone for pneumonitis), checkpoint inhibitor-related hypophysitis causing secondary adrenal insufficiency is increasingly recognized in melanoma patients 7, 8, 5. The TSH is normal (1.32), making concurrent central hypothyroidism unlikely, but monitor thyroid function in 4-6 weeks as checkpoint inhibitor endocrinopathies can evolve 6, 9, 10.

The low cortisol with normal potassium (4.3) confirms secondary (central) adrenal insufficiency rather than primary Addison's disease, so mineralocorticoid (fludrocortisone) is NOT needed 1, 4.

Resuming Checkpoint Inhibitor Therapy

Once adrenal insufficiency is controlled on stable replacement, checkpoint inhibitor therapy can be cautiously resumed if oncologically indicated, with close endocrine monitoring 5. However, the pneumonitis history requires pulmonary clearance first. Glucocorticoid replacement does NOT interfere with checkpoint inhibitor efficacy 3.

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