What is the immediate emergency management of an active seizure (status epilepticus) in adults and children?

Immediate Emergency Management of Active Seizure (Status Epilepticus)

Administer intravenous lorazepam 4 mg at 2 mg/min immediately for any actively seizing patient—this terminates seizures in 65% of cases and is superior to all other first-line options. 1, 2

Critical Pre-Treatment Actions (0–2 minutes)

• Have airway equipment (bag-valve-mask, intubation set) immediately available before giving any benzodiazepine, as respiratory depression requiring intervention is predictable. 1, 2
• Check fingerstick glucose immediately and correct hypoglycemia while administering lorazepam—this is a rapidly reversible cause that must not be missed. 1, 3
• Establish IV access, start high-flow oxygen, and monitor vital signs continuously. 3

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First-Line Treatment: Benzodiazepines (0–5 minutes)

Lorazepam (Preferred Agent)

• Give lorazepam 4 mg IV at 2 mg/min for adults ≥18 years. 1, 2
• Lorazepam achieves 59.1% seizure termination versus 42.6% for diazepam and has longer duration of action than other benzodiazepines. 1
• If seizures continue after 10–15 minutes, give a second 4 mg dose (maximum 8 mg total). 2
• Pediatric dose: 0.1 mg/kg IV (maximum 2 mg per dose) for convulsive SE; may repeat once after ≥1 minute. 1

Alternative Routes When IV Access Unavailable

• Intramuscular midazolam 0.2 mg/kg (maximum 6 mg) if IV access is delayed—this has 97% relative efficacy compared to IV lorazepam. 1
• Intranasal midazolam or buccal midazolam are acceptable alternatives with onset within 1–2 minutes. 1
• Rectal diazepam 0.5 mg/kg if IM/intranasal routes are not feasible. 1
• Never use intramuscular diazepam due to erratic absorption. 1

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Second-Line Treatment: Non-Sedating Anticonvulsants (5–20 minutes)

If seizures persist after adequate benzodiazepine dosing, immediately escalate to one of the following second-line agents—do not delay. 1, 3

Valproate (Preferred for Safety Profile)

• Dose: 20–30 mg/kg IV (maximum 3000 mg) over 5–20 minutes. 1
• Efficacy: 88% seizure cessation with 0% hypotension risk—superior safety profile compared to phenytoin. 1
• Absolute contraindication: Women of childbearing potential due to fetal teratogenicity. 1

Levetiracetam (Preferred for Minimal Monitoring)

• Dose: 30 mg/kg IV (maximum 2500–3000 mg) over 5 minutes. 1, 3
• Efficacy: 68–73% seizure cessation with minimal cardiovascular effects (0.7% hypotension risk). 1
• No cardiac monitoring required—ideal for elderly patients or those with cardiac disease. 1
• Requires renal dose adjustment: reduce by 50% if CrCl <30 mL/min. 1

Fosphenytoin (Traditional Agent)

• Dose: 20 mg PE/kg IV at maximum rate of 150 PE/min (not to exceed 50 mg/min in elderly). 1
• Efficacy: 84% but 12% hypotension risk—requires continuous ECG and blood pressure monitoring. 1
• May be ineffective in alcohol withdrawal or toxin-related seizures. 3

Phenobarbital (Reserve Option)

• Dose: 20 mg/kg IV over 10 minutes (maximum 1000 mg). 1
• Efficacy: 58.2% but higher risk of respiratory depression and hypotension. 1
• Pediatric maintenance: 1–3 mg/kg IV every 12 hours. 1

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Simultaneous Evaluation for Reversible Causes

While administering anticonvulsants, immediately search for and treat underlying etiologies—do not delay treatment to obtain imaging. 1, 3

• Hypoglycemia: Check fingerstick glucose; give dextrose 50% 50 mL IV if <60 mg/dL. 1
• Hyponatremia: Most common electrolyte cause; check sodium and correct cautiously. 1
• Hypoxia: Maintain SpO₂ >94% with supplemental oxygen. 3
• Drug toxicity or withdrawal: Alcohol, benzodiazepines, anticonvulsants. 1, 3
• CNS infection: Check temperature; consider meningitis/encephalitis. 3
• Acute stroke or hemorrhage: Especially in patients >40 years. 1

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Refractory Status Epilepticus (20+ minutes): Third-Line Anesthetic Agents

Refractory SE is defined as seizures continuing despite benzodiazepines and one second-line agent—initiate continuous EEG monitoring and transfer to ICU immediately. 1, 3

Midazolam Infusion (First-Choice Anesthetic)

• Loading dose: 0.15–0.20 mg/kg IV bolus. 1, 4
• Continuous infusion: 1 mg/kg/min, titrate up by 1 mg/kg/min every 15 minutes to maximum 5 mg/kg/min. 1
• Efficacy: 80% seizure control with 30% hypotension risk—lowest hypotension rate among anesthetics. 1, 4
• Before tapering midazolam, load a long-acting anticonvulsant (phenytoin, valproate, or levetiracetam) to prevent breakthrough seizures. 1

Propofol (Alternative Anesthetic)

• Loading dose: 2 mg/kg IV bolus. 1, 4
• Continuous infusion: 3–7 mg/kg/hour. 1
• Efficacy: 73% with 42% hypotension risk—requires mechanical ventilation but shorter duration (4 days) than barbiturates (14 days). 1, 4
• Mean time to seizure control: 2.6 minutes (fastest among anesthetics). 4

Pentobarbital (Highest Efficacy, Highest Risk)

• Loading dose: 13 mg/kg IV bolus. 1, 4
• Continuous infusion: 2–3 mg/kg/hour. 1
• Efficacy: 92%—highest among all anesthetic agents—but 77% hypotension risk requiring vasopressor support. 1, 4
• Prolonged mechanical ventilation (mean 14 days). 4

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Critical Monitoring Requirements for Anesthetic Agents

• Continuous EEG monitoring is mandatory—not optional—to titrate anesthetic depth and detect electrographic seizures (25% of patients have ongoing electrical seizures despite cessation of motor activity). 1, 4, 3
• Mechanical ventilation is required for all anesthetic agents due to respiratory depression. 4
• Prepare vasopressors (norepinephrine, phenylephrine) before initiating therapy, as hypotension is nearly universal. 4
• Continue EEG monitoring for at least 24–48 hours after anesthetic discontinuation, as breakthrough seizures occur in >50% of patients. 1

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Super-Refractory Status Epilepticus (SRSE)

SRSE is defined as seizures continuing despite anesthetic therapy or recurring during anesthetic wean—mortality approaches 40%. 4, 5

• Immediately administer continuous IV anesthetic infusions titrated to EEG burst suppression. 4
• Consider ketamine (0.45–2.1 mg/kg/hour) as a fourth-line agent—64% efficacy when started early (within 3 days) but only 32% if delayed. 1
• Patients with toxic/metabolic causes or anoxia have worse outcomes (29% control) versus chronic epilepsy, infections, or stroke (91% control). 4

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Critical Pitfalls to Avoid

• Never use neuromuscular blockers (e.g., rocuronium) alone—they only mask motor manifestations while allowing continued electrical seizure activity and brain injury. 1
• Do not skip to third-line agents until benzodiazepines and a second-line agent have been tried. 1
• Do not assume seizures have stopped based on cessation of motor activity alone—obtain EEG to confirm, as nonconvulsive SE occurs in 25% of cases. 1, 3
• Do not delay second-line treatment—every minute of ongoing seizures increases morbidity and mortality (5–22% overall, up to 65% in refractory cases). 1
• Do not underdose anticonvulsants—use full weight-based dosing to avoid treatment failure. 3

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Maintenance Dosing After Seizure Control

• Levetiracetam: 30 mg/kg IV every 12 hours (maximum 1500 mg per dose) for convulsive SE; 15 mg/kg every 12 hours for nonconvulsive SE. 1
• Valproate: Continue at maintenance dose based on serum levels. 1
• Fosphenytoin/Phenytoin: Transition to oral phenytoin 300–400 mg daily in divided doses. 6