IV Hydrocortisone Dosing for 46 kg, 11-Year-Old Child
For an 11-year-old child weighing 46 kg (>25 kg), administer 100 mg IV hydrocortisone as the initial stress dose, followed by maintenance dosing of 50-100 mg/m²/24h divided every 6 hours, depending on the clinical indication. 1
Clinical Context Determines Exact Dosing
The appropriate dose depends critically on why the child needs hydrocortisone:
For Acute Adrenal Crisis
- Initial bolus: 50-100 mg/m² IV (or 100 mg for children >25 kg) 2, 1
- Maintenance: 50-100 mg/m²/24h divided every 6 hours OR as continuous IV infusion at 2-3 mg/m²/h 1
- The 2021 Endocrine guideline provides a simplified weight-based approach: 100 mg IV for children >25 kg 1
For Major Surgery/Trauma/ICU-Level Stress
For Minor-Moderate Surgical Stress
- 50 mg/m² IM or double/triple oral replacement doses 2
Body Surface Area Calculation
For precise dosing using the mg/m² approach:
- An 11-year-old weighing 46 kg has approximately 1.4 m² body surface area
- Initial crisis dose: 50-100 mg/m² = 70-140 mg (the guideline simplifies this to 100 mg for >25 kg) 1
- Maintenance: 50-100 mg/m²/24h = 70-140 mg/24h divided every 6 hours = 17.5-35 mg every 6 hours
Critical Implementation Points
The 2021 Endocrine guideline emphasizes that under-dosing glucocorticoids in adrenal crisis is potentially hazardous 2. When in doubt, err on the side of higher dosing initially.
Fluid Resuscitation is Mandatory
- If shocked: 10-20 mL/kg 0.9% sodium chloride IV bolus (460-920 mL for this child), repeat as necessary up to 60 mL/kg total 1
- Continue maintenance fluids with 0.9% sodium chloride + 5% glucose 1
Monitoring Requirements
- Blood glucose hourly - if <3.5 mmol/L (63 mg/dL), give 2-5 mL/kg of 10% dextrose 1
- Electrolytes (sodium, potassium)
- Blood pressure and cardiac function
- Fludrocortisone is NOT required acutely when high-dose hydrocortisone is given 1
Tapering Strategy
Once stabilized (typically 48-72 hours):
- Transition to oral hydrocortisone at 30-50 mg/m²/24h (42-70 mg/24h for this child) 1
- Gradually reduce to maintenance level
- Start fludrocortisone 0.05-0.1 mg daily when transitioning to oral therapy 1
Common Pitfalls to Avoid
- Don't delay treatment waiting for diagnostic confirmation - treat suspected adrenal crisis immediately 2
- Don't use dexamethasone as first-line (it's the least-preferred alternative) 2
- Don't forget fluid resuscitation - hydrocortisone alone is insufficient 1
- Don't continue high-dose therapy beyond 48-72 hours without reassessment - risk of hypernatremia 3
- Don't abruptly discontinue after prolonged therapy - taper gradually 3
The evidence strongly supports the simplified weight-based approach from the 2021 guideline for practical bedside use, while the body surface area calculations provide precision when needed for specific clinical scenarios.