What is the treatment for an acute seizure in the Intensive Care Unit (ICU)?

Treatment of Acute Seizures in the ICU

For acute seizures in the ICU, immediately administer intravenous lorazepam 4 mg (0.1 mg/kg, maximum 4 mg) given slowly at 2 mg/min, and if seizures persist after 10-15 minutes, repeat with an additional 4 mg dose. 1, 2 This represents the standard first-line approach with the strongest evidence for both convulsive and non-convulsive seizures in critically ill patients.

Initial Management Algorithm

Immediate Actions

• Assess and secure airway, breathing, and circulation (ABCs) with equipment for airway management immediately available before administering any IV benzodiazepines 3, 1
• Provide high-flow oxygen and ensure adequate ventilation support is readily available 3
• Check blood glucose immediately and correct hypoglycemia if present 3
• Establish IV access and monitor vital signs continuously 3

First-Line Treatment: Benzodiazepines

• Administer lorazepam 0.1 mg/kg IV (maximum 4 mg per dose) at a rate of 2 mg/min 1, 2, 3
• For convulsive status epilepticus: repeat the dose after at least 1 minute if needed, up to a maximum of 2 doses 3
• For non-convulsive status epilepticus: repeat every 5 minutes up to a maximum of 4 doses 3
• Critical pitfall: Underdosing lorazepam (giving less than 4 mg in adults >40 kg) significantly increases progression to refractory status epilepticus (87% vs 62%) 4

Second-Line Treatment (If Seizures Persist After Benzodiazepines)

Administer one of the following agents immediately—all three have equivalent efficacy based on the highest quality evidence (ESETT trial): 2, 3

Option 1: Levetiracetam

• Dose: 40-60 mg/kg IV (maximum 2,500-4,500 mg) given as bolus 3, 2
• Infusion rate: 100 mg/min 2
• Advantages: Favorable side effect profile, minimal drug interactions, no cardiac monitoring required 2, 3
• Disadvantages: May cause nausea and rash 2
• Life-threatening hypotension rate: 0.7% 2

Option 2: Fosphenytoin

• Dose: 18-20 PE/kg IV at maximum rate of 150 PE/min 2, 3
• Advantages: Can be given IM if IV access lost 2
• Disadvantages: Risk of hypotension (3.2% life-threatening) and cardiac dysrhythmias, requires cardiac monitoring 2, 3
• Intubation rate: 26.4% (highest among the three options) 2

Option 3: Valproate

• Dose: 20-40 mg/kg IV at maximum rate of 10 mg/kg/min 2, 3
• Advantages: Rapid administration, minimal cardiorespiratory effects (1.6% life-threatening hypotension) 2, 3
• Disadvantages: Contraindicated in liver disease, risk of thrombocytopenia 2, 3
• Intubation rate: 16.8% (lowest among the three options) 2

The ESETT trial (Class I evidence) demonstrated no significant difference in seizure cessation at 60 minutes: levetiracetam 47%, fosphenytoin 45%, valproate 46%. 2 Selection should be based on patient-specific contraindications and side effect profiles rather than efficacy differences.

Third-Line Treatment: Refractory Status Epilepticus

• If seizures persist after adequate benzodiazepine and second-line agent, add phenobarbital 10-20 mg/kg IV loading dose (maximum 1,000 mg) 3
• Consider transfer to ICU if not already there 3
• Initiate continuous EEG monitoring for refractory seizures 3

Simultaneous Diagnostic Workup

While administering antiseizure medications, immediately investigate and treat reversible causes: 3, 2

• Hypoglycemia (check and treat immediately) 3, 2
• Hyponatremia and other electrolyte abnormalities 3, 2
• Hypoxia (ensure adequate oxygenation) 3, 2
• CNS or systemic infection 3, 2
• Drug toxicity (consider toxicology screen) 3, 2
• Intracranial hemorrhage, ischemic stroke, or mass lesion (neuroimaging if indicated) 3, 2
• Alcohol or benzodiazepine withdrawal 3

EEG Monitoring Recommendations

Urgent EEG (within 60 minutes) is strongly recommended in specific scenarios: 3

• All patients with acute brain injury and unexplained persistent altered consciousness 3
• Patients with convulsive status epilepticus who do not return to functional baseline within 60 minutes after seizure medication 3
• All comatose patients after cardiac arrest, both during therapeutic hypothermia and within 24 hours of rewarming 3
• Comatose ICU patients without primary brain condition but with unexplained mental status impairment or neurological deficits, particularly with severe sepsis or renal/hepatic failure 3

Continuous EEG monitoring is preferred over routine EEG when feasible, as routine EEG misses approximately 50% of non-convulsive seizures. 3

Maintenance Therapy After Seizure Control

After resolution of status epilepticus, continue maintenance dosing: 3

• Lorazepam: 0.05 mg/kg (maximum 1 mg) IV every 8 hours for 3 doses 3
• Levetiracetam: 15-30 mg/kg IV every 12 hours (maximum 1,500 mg) 3
• Phenobarbital: 1-3 mg/kg IV every 12 hours if used 3

Critical Pitfalls to Avoid

• Never underdose lorazepam: Adults >40 kg should receive the full 4 mg dose, as lower doses dramatically increase progression to refractory status epilepticus 4
• Do not overlook non-convulsive seizures: Up to 50% may be missed without continuous EEG monitoring 3
• Avoid abrupt discontinuation of sedatives after prolonged use: Taper over several days to prevent withdrawal seizures 3, 5
• Do not use prophylactic anticonvulsants for single self-limiting seizures: A single seizure within 24 hours of ischemic stroke should not be treated with long-term anticonvulsants 3
• Recognize that benzodiazepines may cause respiratory depression and hypotension: Have airway management equipment immediately available 1, 6
• Do not fail to address the underlying cause: Treating only the seizure without identifying and correcting the precipitant leads to recurrence 3, 2

Special Considerations for ICU Sedation

If ongoing sedation is required in ICU patients with seizures: 3, 5

• Prefer dexmedetomidine over benzodiazepine infusions to reduce delirium risk 3, 5
• Target light sedation levels using daily sedation interruption or light sedation protocols 3, 5
• Use EEG monitoring to detect non-convulsive seizure activity and to titrate burst suppression therapy in patients with elevated intracranial pressure 3