What is the appropriate evaluation and treatment for a child who ingested rock salt and may have hypernatremia and volume depletion?

Treatment for Rock Salt Ingestion in Children

Immediately initiate slow correction of hypernatremia using hypotonic fluids (5% dextrose in water or 0.45% saline), targeting a reduction rate of 0.5 mmol/L/hour with a maximum of 10-15 mmol/L per 24 hours to prevent fatal cerebral edema. 1, 2

Immediate Assessment

Upon presentation, rapidly evaluate the following:

• Neurological status: Check for altered mental status, seizures, irritability, lethargy, or coma—these indicate severe hypernatremia requiring urgent intervention 1
• Volume status: Assess for signs of dehydration including dry mucous membranes, sunken eyes, poor skin turgor, and vital sign abnormalities 3, 1
• Obtain stat labs: Serum sodium, potassium, chloride, glucose, BUN, creatinine, and blood gas to assess severity and acid-base status 1

Rock salt ingestion can cause extreme hypernatremia—case reports document serum sodium levels as high as 234 mmol/L in a surviving child, making this a life-threatening emergency 4. Even small amounts (approximately 4 tablespoons) can cause severe toxicity 4.

Fluid Resuscitation Protocol

Initial Fluid Selection

Use hypotonic fluids as primary therapy—NEVER use normal saline (0.9% NaCl), which will worsen hypernatremia due to its high sodium content (154 mmol/L). 1, 2, 5

Appropriate fluid choices include:

• 5% dextrose in water (D5W) for severe hypernatremia 1, 2
• 0.45% saline (half-normal saline) containing 77 mEq/L sodium for moderate cases 2
• 0.18% saline (quarter-normal saline) containing ~31 mEq/L sodium for more aggressive free water replacement 2

Calculate Fluid Requirements

Use the following physiological demand calculation 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 above 20 kg

Add replacement for ongoing losses (vomiting, diarrhea) and estimated deficit based on degree of dehydration 1.

Critical Correction Rate

The rate of sodium correction is the most crucial factor determining survival and neurological outcome:

• Target rate: 0.5 mmol/L/hour 1
• Maximum rate: 10-15 mmol/L per 24 hours 1, 2, 5
• Target timeframe: Normalize serum sodium within 48-72 hours 1

Rationale: In hypernatremia lasting more than a few hours, brain cells generate idiogenic osmoles to protect against volume loss. Rapid correction causes these cells to swell, leading to cerebral edema, seizures, and permanent neurological injury or death 2, 5, 6. Literature review shows that correction rate—not the type of therapy—determines survival 7.

Monitoring Protocol

Frequent Laboratory Assessment

• Check serum sodium every 2-4 hours initially during active correction, then every 6-12 hours once stable 2
• Daily monitoring of complete metabolic panel, weight, and fluid balance 1, 2
• Watch for cerebral edema signs: Worsening mental status, new seizures, or increased lethargy during correction 1

Clinical Monitoring

• Neurological checks every 1-2 hours initially, watching for seizure activity or deterioration 1
• Strict intake/output documentation including urine output, specific gravity, and ongoing losses 2
• Daily weights to assess fluid balance 1, 2

Management of Complications

Seizures

If seizures occur (common with severe hypernatremia):

• Administer antiseizure medication (benzodiazepines first-line) 8
• Do NOT increase correction rate—seizures may occur from the hypernatremia itself or from too-rapid correction 8, 6
• Continue slow, controlled sodium reduction 8

Severe Hypertension

If life-threatening hypertension develops:

• Reduce blood pressure by no more than 25% of planned reduction over first 8 hours 1
• Use short-acting antihypertensive agents 1

Special Considerations for Salt Poisoning

Unique Aspects of Rock Salt Ingestion

Unlike gradual hypernatremia from dehydration, salt poisoning represents acute massive sodium loading over minutes to hours 6, 4. This creates several critical differences:

• Higher mortality risk: 50% mortality in acute salt toxicity cases 6
• Risk of intracerebral hemorrhage: Severe hypernatremia causes brain shrinkage and vessel tearing, leading to massive hemorrhage 8, 6
• Preserved urine output: Unlike dehydration, kidneys often maintain generous urine output with high urinary sodium, allowing fluid therapy alone to be effective 9

Prognostic Factors

Literature review identifies two key predictors of survival 7:

• Age: Younger children (infants) have better survival than older children and adults
• Initial sodium level: Lower initial sodium concentrations predict better outcomes

The highest documented serum sodium in a survivor was 234 mmol/L in a 6-year-old 4, though most fatal cases involve levels >200 mmol/L 7.

Common Pitfalls to Avoid

1. Using isotonic saline (0.9% NaCl): This contains 154 mmol/L sodium and will worsen hypernatremia 1, 2, 5

2. Correcting too rapidly: Even if the child appears critically ill, rapid correction causes cerebral edema and is often fatal 1, 2, 5, 6

3. Inadequate monitoring frequency: Sodium must be checked every 2-4 hours initially to ensure correction rate stays within safe limits 2

4. Failing to calculate free water deficit: Use the formula: Desired Na decrease (mmol/L) × (0.5 × ideal body weight in kg) to determine total fluid requirements 2

5. Stopping correction prematurely: Continue until sodium normalizes over 48-72 hours, not just until symptoms improve 1

Disposition and Follow-up

• All cases require ICU admission for continuous monitoring and frequent lab checks 8, 6, 9
• Mechanical ventilation may be needed if pulmonary edema or severe neurological depression develops 9
• Neuroimaging (CT or MRI) should be obtained if neurological symptoms are present to assess for intracranial hemorrhage 8
• Long-term follow-up is essential as neurological sequelae may not be immediately apparent 8
• Mandatory reporting and parent education: Salt poisoning in children often represents inadequate supervision or intentional harm; careful investigation and education on proper formula preparation is required 8, 6, 4