What is the immediate management for a child experiencing seizures due to hyponatremia?

Immediate Management of Hyponatremia-Induced Seizures in Children

For a child actively seizing due to hyponatremia, immediately administer 3% hypertonic saline as a bolus of 4-6 mL/kg over 10 minutes, targeting a rapid sodium increase of 4-6 mmol/L to abort the seizure, while simultaneously providing basic seizure management (airway protection, positioning on side, clearing area). 1, 2, 3

Initial Emergency Actions

Airway and Safety First:

• Help the child to the ground if seizing, place on their side in recovery position to prevent aspiration 4
• Clear the area around them to minimize injury risk 4
• Do NOT restrain the child or put anything in their mouth 4
• Provide high-flow oxygen and ensure airway patency 4
• Stay with the child throughout the seizure 4

Immediate Hypertonic Saline Administration:

• Administer 3% hypertonic saline as a bolus of 4-6 mL/kg body weight intravenously over 10 minutes 2, 3
• This typically achieves a sodium increase of 3-5 mmol/L within the first hour, which is sufficient to abort hyponatremic seizures 2, 5
• Hypertonic saline is more effective than traditional anticonvulsants for hyponatremia-induced seizures and should be the primary treatment 2, 3

Why Hypertonic Saline is Superior to Anticonvulsants

Traditional anticonvulsants (benzodiazepines, phenobarbital) have a high failure rate in hyponatremic seizures, with 13 treatment failures and 10 instances of apnea occurring in 28 patients treated with benzodiazepine/phenobarbital alone 2. In contrast, hypertonic saline resolved seizures and apnea in all cases when administered 2. Early use of 3% saline reduces morbidity from anticonvulsant therapy and intubation requirements 3.

Correction Rate Guidelines

For Acute Symptomatic Hyponatremia with Seizures:

• Initial target: Increase sodium by 4-6 mmol/L over the first 6 hours or until seizures resolve 1, 6
• Maximum total correction: 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 1, 6, 2
• If 6 mmol/L is corrected in the first 6 hours, only 2 mmol/L additional correction is allowed in the next 18 hours 1

Critical Safety Point: Acute hyponatremia (<48 hours duration) can be corrected more rapidly without risk of osmotic demyelination syndrome, but chronic hyponatremia (>48 hours) requires strict adherence to the 8 mmol/L/24-hour limit 5, 7

Monitoring Protocol

Frequent Sodium Checks:

• Every 2 hours during active seizure management and initial correction phase 1, 6
• Every 4 hours after seizure resolution until stable 1, 6
• Calculate sodium deficit: Desired increase (mEq/L) × (0.5 × ideal body weight in kg) 1

Adjunctive Anticonvulsant Use

If seizures persist despite hypertonic saline or if the child has a seizure disorder:

• Lorazepam 0.1 mg/kg IV/IO may be given as adjunctive therapy 4
• Anticonvulsants should be used alongside hypertonic saline, not as monotherapy 8
• Phenytoin can be added after hypertonic saline to prevent recurrent seizures during gradual sodium correction 8

When to Activate Emergency Medical Services

Activate EMS immediately if: 4

• First-time seizure in any child
• Seizure in an infant <6 months of age
• Seizure lasting >5 minutes
• Multiple seizures without return to baseline between episodes
• Child does not return to baseline within 5-10 minutes after seizure stops
• Seizure with difficulty breathing or traumatic injuries

Subsequent Management After Seizure Control

Volume Status Assessment:

• Determine if hypovolemic (dry mucous membranes, decreased skin turgor, sunken fontanelle, tachycardia), euvolemic, or hypervolemic (edema, weight gain) 6
• Check urine sodium: <20 mmol/L suggests sodium depletion; >20 mmol/L with oliguria suggests water overload 6

Ongoing Treatment Based on Volume Status:

• Hypovolemic: Continue 0.9% normal saline for volume repletion 6
• Euvolemic: Fluid restriction to 50-60 mL/kg/day (approximately 2/3 of maintenance) 6
• Hypervolemic: Fluid restriction to 50-60 mL/kg/day and treat underlying condition 6

Maintenance Fluids:

• Use isotonic solutions (0.9% NaCl with 5% dextrose) for ongoing IV fluid needs 6
• Avoid hypotonic fluids as they increase hyponatremia risk 6

Common Pitfalls to Avoid

• Never delay hypertonic saline while waiting for anticonvulsants to work—hyponatremic seizures require sodium correction 2, 3
• Never exceed 8 mmol/L correction in 24 hours in chronic hyponatremia to prevent osmotic demyelination syndrome 1, 5
• Never use fluid restriction as initial treatment for a seizing child—this is a medical emergency requiring immediate sodium correction 1
• Never give oral medications or fluids to a seizing child or one with decreased responsiveness 4

Risk Factors for Hyponatremic Seizures in Children

Children at highest risk include: 3

• Age <6 months
• Formula-fed infants receiving excessive solute-poor fluid (diluted formula, excessive water)
• Hypothermia, hyperglycemia, low bicarbonate
• No significant medical history or recent febrile illness