What is the appropriate workup and acute management for an Addison disease (primary adrenal insufficiency) flare-up?

Workup and Acute Management of Addison Disease Flare-Up (Adrenal Crisis)

Immediately administer hydrocortisone 100 mg IV bolus and begin 0.9% saline 1 L over the first hour without awaiting diagnostic confirmation—treatment delay increases mortality. 1

Immediate Recognition and Clinical Triggers

Suspect adrenal crisis when patients present with:

• Hypotension (often <90/60 mmHg) with or without shock—orthostatic drops appear before supine hypotension 1
• Severe dehydration with low jugular venous pressure 1
• Gastrointestinal symptoms: marked nausea/vomiting, abdominal pain, diarrhea 1
• Altered mental status: confusion, somnolence, obtundation, or coma 1
• Muscle pain and cramps 1
• Hyperpigmentation (in primary adrenal insufficiency due to elevated ACTH) 1

Critical pitfall: Non-specific malaise and somnolence are early warning signs—do not wait for supine hypotension to develop, as orthostatic changes occur first. 1

Laboratory Workup (Draw Before Treatment, But Never Delay Therapy)

Obtain blood samples immediately if feasible, but never postpone hydrocortisone while awaiting results: 1

Essential Immediate Labs:

• Serum cortisol and ACTH: Cortisol <250 nmol/L (~9 µg/dL) with elevated ACTH confirms primary adrenal insufficiency 1, 2
• Electrolytes: Hyponatremia present in ~90% of cases; hyperkalemia in only ~50% 1
• Creatinine and BUN: Elevated from prerenal azotemia due to volume depletion 1
• Glucose: Hypoglycemia more common in children but can occur in adults 1
• Blood cultures and infection workup: Infections are the most common precipitant 1

Expected Laboratory Findings:

• Hyponatremia (~90% of cases) 1
• Hyperkalemia (~50% of cases—absence does NOT exclude crisis) 1
• Mild hypercalcemia (10-20% of cases) 1
• Metabolic acidosis from impaired renal function 1
• Elevated creatinine/BUN from prerenal renal failure 1

Important caveat: Normal or even elevated plasma cortisol does not exclude relative adrenal insufficiency in physiologically stressed patients. 1

Emergency Treatment Protocol: First Hour

The cornerstone is immediate glucocorticoid and volume replacement: 1

1. Hydrocortisone 100 mg IV bolus immediately—this dose saturates 11β-hydroxysteroid dehydrogenase type 2 to provide both glucocorticoid and mineralocorticoid activity 1, 3

2. Rapid volume expansion with 0.9% isotonic saline 1 L IV over the first hour 1, 4

3. If IV access cannot be rapidly established: Give hydrocortisone 100 mg IM as backup 1

4. Draw blood samples for cortisol, ACTH, electrolytes, creatinine, urea, and glucose before starting treatment if possible 1, 3

Ongoing Management: First 24-48 Hours

Glucocorticoid Continuation:

• Preferred: Hydrocortisone 200 mg per 24 hours as continuous IV infusion 1, 4
• Alternative: Hydrocortisone 50 mg IV or IM every 6 hours (total 200 mg/day) 1, 3

Fluid Management:

• Continue isotonic saline at slower rate, delivering total of 3-4 L over 24-48 hours 1, 4
• Monitor hemodynamics frequently to prevent fluid overload 1
• Consider 5% dextrose in isotonic saline if hypoglycemia present 1

Supportive Care:

• Gastric stress-ulcer prophylaxis 1, 4
• Low-dose heparin for DVT prophylaxis 1, 4
• Frequent blood glucose monitoring, especially in children 1
• Monitor serum electrolytes frequently to guide fluid management 1

Critical Care Considerations:

• Admit to ICU or high-dependency unit if persistent hypotension or severe presentation 1, 4
• Treat precipitating infections promptly with appropriate antimicrobial therapy 1, 3

Do NOT add separate mineralocorticoid (fludrocortisone) during acute crisis—high-dose hydrocortisone provides adequate mineralocorticoid activity. 1

Common Precipitating Factors to Investigate

• Gastrointestinal illness with vomiting/diarrhea (most frequent trigger) 1, 4
• Any type of infection 1, 4
• Surgical procedures without adequate steroid coverage 1
• Physical trauma or injuries 1
• Medication non-compliance or failure to increase doses during illness 1
• Myocardial infarction 1
• Severe allergic reactions 1
• Starting thyroid hormone replacement before adequate glucocorticoid replacement in patients with multiple hormone deficiencies 1

Transition to Maintenance Therapy

Once the precipitating illness permits and oral intake is tolerated: 1, 4

• Taper parenteral glucocorticoids over 1-3 days to oral therapy 1, 4
• Resume oral hydrocortisone and double the usual dose for 48 hours after resuming oral intake 1
• Re-introduce fludrocortisone only after hydrocortisone dose falls below 50 mg per day—lower doses no longer provide sufficient mineralocorticoid activity 1

Etiologic Workup After Stabilization

To determine the underlying cause of primary adrenal insufficiency: 1

• 21-hydroxylase autoantibodies (21OH-Ab): Positive in ~85% of autoimmune Addison disease cases 1
• CT scan of adrenals if 21OH-Ab negative—evaluate for hemorrhage, tumor, tuberculosis, or infiltrative processes 1
• Very long chain fatty acids (VLCFA) if adrenoleukodystrophy suspected (especially in males) 1, 2

Prevention of Recurrent Crises

Patient education is paramount to preventing unnecessary deaths: 1

• Teach patients to double or triple oral glucocorticoid doses during minor illness with fever 1, 3, 4
• Prescribe emergency injectable hydrocortisone 100 mg IM for use during severe illness or inability to take oral medications 1, 3, 2
• Provide medical alert identification jewelry and emergency steroid card 1, 4
• Evaluate for chronic under-replacement with fludrocortisone, low salt intake, poor compliance, or psychiatric disorders in patients with recurrent crises 1

Common pitfall: Even mild upset stomach may precipitate crisis as patients cannot absorb oral medication when they need it most. 1