Treatment of Hypernatremia in Children
The primary treatment for hypernatremia in children is slow correction using hypotonic fluids (5% dextrose in water), targeting a reduction rate of approximately 0.5 mmol/L/hour, with a maximum correction of 10-15 mmol/L per 24 hours to prevent cerebral edema. 1, 2
Initial Assessment and Monitoring
Before initiating treatment, evaluate the following:
- Clinical status and neurological symptoms including altered mental status, seizures, irritability, lethargy, or coma 1
- Body weight and degree of dehydration to estimate fluid deficits 1
- Serum electrolytes (sodium, potassium, chloride) and acid-base status 1
- Volume status to determine if hypernatremia is hypovolemic, euvolemic, or hypervolemic 3
Fluid Selection and Administration
Primary Rehydration Strategy
- Use hypotonic fluids (5% dextrose in water) as the primary rehydration fluid 1
- Avoid normal saline (0.9% NaCl) as it can worsen hypernatremia due to its high sodium content 1, 4
- For unstable patients with severe hypernatremia, isotonic intravenous fluid may be used initially for volume resuscitation 2
Fluid Rate Calculation
Calculate initial fluid rate based on physiological demand 1:
- 100 ml/kg/24h for the first 10 kg of body weight
- 50 ml/kg/24h (additional) for 10-20 kg
- 20 ml/kg/24h (additional) for remaining weight
Correction Rate Guidelines
Target Correction Speed
- Aim for 0.5 mmol/L/hour reduction in serum sodium 1
- Maximum correction should not exceed 10-15 mmol/L per 24 hours to prevent cerebral edema 1, 2, 3
- Target normalization within 48-72 hours 1
Acute vs. Chronic Hypernatremia
- Acute hypernatremia (developed rapidly): Can tolerate faster correction to prevent cellular dehydration effects 3
- Chronic hypernatremia (developed over days): Requires slow correction rate (no more than 0.4 mmol/L/h) to avoid cerebral edema 3
The distinction is critical because correcting chronic hypernatremia too rapidly can lead to cerebral edema, seizures, and permanent neurological injury 5, 4
Monitoring During Treatment
Frequency of Assessment
- Monitor serum electrolytes and weight daily during initial treatment days 1
- Adjust monitoring intervals based on clinical status and patient stability 1
- Watch closely for signs of cerebral edema including altered mental status and seizures during correction 1
Additional Considerations
- Ensure adequate caloric intake alongside rehydration, especially in infants 1
- In stable patients, aim for correction over 24-48 hours with maximal change in serum sodium between 8-12 mEq/L over the first 24 hours 2
Special Clinical Scenarios
Acute Severe Hypernatremia with Life-Threatening Symptoms
- If hypertension is present, initiate short-acting antihypertensive medication immediately 1
- Reduce blood pressure by no more than 25% of the planned reduction over the first 8 hours 1
Infants and Breastfed Babies
- Breastfed infants are at high risk for hypernatremia in the outpatient setting due to insufficient lactation 4
- Monitor closely for inadequate intake and provide lactation support 4
- Consider judicious infant formula supplementation until lactation problems are corrected 4
Critical Pitfalls to Avoid
Common Errors in Management
- Using normal saline as primary rehydration fluid will worsen hypernatremia 1, 4
- Failing to monitor serum electrolytes frequently during initial rehydration 1
- Inadequate fluid volume calculation that doesn't account for ongoing losses 1
- Too rapid correction leading to cerebral edema, particularly in chronic hypernatremia 5, 4, 3
High-Risk Situations
- Hospital-acquired hypernatremia occurs in patients with restricted access to fluids combined with ongoing free-water losses 4
- This could largely be prevented by providing adequate free-water when mild hypernatremia (Na >145 mEq/L) develops 4
- For patients with secondary nephrogenic diabetes insipidus, avoid salt supplementation 1
Underlying Cause Management
While correcting the sodium level, address the underlying etiology: