What is the emergency department management of an acute seizure, including airway and breathing support, point‑of‑care glucose assessment, benzodiazepine dosing for adults and children, second‑line antiepileptic options, recommended laboratory tests and imaging, and disposition criteria?

Emergency Department Management of Acute Seizures

Immediate First-Line Treatment (0-5 Minutes)

Administer IV lorazepam 4 mg at 2 mg/min immediately for any actively seizing patient—this terminates status epilepticus in 65% of cases and is superior to diazepam (59.1% vs 42.6% seizure cessation). 1

• Have airway equipment immediately available before administering any benzodiazepine due to respiratory depression risk 1
• Check fingerstick glucose simultaneously while administering treatment—hypoglycemia is rapidly reversible but rare (only 1.2% of seizure patients) 1, 2
• Do not delay benzodiazepine administration to obtain glucose testing—this causes a 2.1-5.9 minute delay without meaningful clinical benefit 2
• Status epilepticus is defined as seizure lasting ≥5 minutes or recurrent seizures without regaining consciousness 1

Alternative Benzodiazepine Routes When IV Access Unavailable

• IM midazolam 0.2 mg/kg (maximum 6 mg) if IV access is challenging—equally efficacious to IV lorazepam 1, 3, 4
• Intranasal midazolam provides onset within 1-2 minutes with peak effect at 3-4 minutes 1
• Rectal diazepam 0.5 mg/kg if buccal/intranasal routes not feasible 1
• Never use IM diazepam due to erratic absorption—use rectal route instead 1

Pediatric Benzodiazepine Dosing

• Lorazepam 0.1 mg/kg IV (maximum 2 mg) for convulsive status epilepticus, repeat after 1 minute up to 2 doses 1
• Lorazepam 0.05 mg/kg IV (maximum 1 mg) for non-convulsive status epilepticus, repeat every 5 minutes up to 4 doses 1

Second-Line Anticonvulsant Therapy (5-20 Minutes)

If seizures persist after adequate benzodiazepine dosing, immediately escalate to one of the following second-line agents—do not skip to third-line agents until these have been tried. 1

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 in women of childbearing potential due to fetal teratogenic risk 1
• No cardiac monitoring required 1

Levetiracetam (Preferred for Minimal Adverse Effects)

• Dose: 30 mg/kg IV (maximum 2500-3000 mg) over 5 minutes 1
• Efficacy: 68-73% seizure cessation with minimal cardiovascular effects 1
• Hypotension risk ≈0.7%, intubation rate 20% 1
• No cardiac monitoring required 1
• Maintenance dosing: 30 mg/kg IV every 12 hours (maximum 1500 mg) for convulsive SE; 15 mg/kg every 12 hours for non-convulsive SE 1

Levetiracetam Renal Dose Adjustments

• CrCl >80 mL/min: 500-1500 mg every 12 hours 1
• CrCl 50-80 mL/min: 500-1000 mg every 12 hours 1
• CrCl 30-50 mL/min: 250-750 mg every 12 hours 1
• CrCl <30 mL/min: 250-500 mg every 12 hours 1
• ESRD on dialysis: 500-1000 mg every 24 hours 1

Fosphenytoin (Traditional Agent, Higher Risk)

• Dose: 20 mg PE/kg IV at maximum rate of 50 mg/min (150 PE/min) 1
• Efficacy: 84% seizure cessation but 12% hypotension risk 1
• Requires continuous ECG and blood pressure monitoring due to cardiovascular toxicity 1
• Intubation rate 26.4% 1
• Pediatric rate should not exceed 1-3 mg/kg/min or 50 mg/min, whichever is slower 1

Phenobarbital (Highest Respiratory Depression Risk)

• Dose: 20 mg/kg IV over 10 minutes (maximum 1000 mg) 1
• Efficacy: 58.2% seizure cessation as initial second-line agent 1
• Higher risk of respiratory depression and hypotension due to vasodilatatory and cardiodepressant effects 1
• Pediatric maintenance: 1-3 mg/kg IV every 12 hours 1

Refractory Status Epilepticus (20+ Minutes)

Refractory SE is defined as seizures continuing despite benzodiazepines and one second-line agent—initiate continuous EEG monitoring at this stage. 1

Midazolam Infusion (First-Choice Anesthetic)

• Loading dose: 0.15-0.20 mg/kg IV 1
• Maintenance: 1 mg/kg/min continuous infusion, 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 1
• Load with phenytoin/fosphenytoin, valproate, levetiracetam, or phenobarbital during midazolam infusion to ensure adequate long-acting anticonvulsant levels before tapering 1

Propofol (Requires Mechanical Ventilation)

• Loading dose: 2 mg/kg bolus 1
• Maintenance: 3-7 mg/kg/hour infusion 1
• Efficacy: 73% seizure control with 42% hypotension risk 1
• Requires mechanical ventilation but shorter duration than barbiturates (4 days vs 14 days) 1
• Continuous blood pressure monitoring essential—propofol causes hypotension in 42% of patients 1

Pentobarbital (Highest Efficacy, Highest Risk)

• Loading dose: 13 mg/kg bolus 1
• Maintenance: 2-3 mg/kg/hour infusion 1
• Efficacy: 92% seizure control but 77% hypotension risk requiring vasopressors 1
• Prolonged mechanical ventilation (mean 14 days) 1
• Have vasopressors immediately available (norepinephrine or phenylephrine) as hypotension is nearly universal 1

Simultaneous Evaluation for Reversible Causes

While administering anticonvulsants, promptly identify and treat underlying etiologies—do not postpone anticonvulsant therapy to obtain neuroimaging. 1

Critical Laboratory Tests

• Serum glucose and sodium—the only laboratory tests that consistently alter acute ED management 5, 6
• Complete blood count to evaluate for infection, anemia, or hematologic abnormalities 5
• Basic metabolic panel for electrolyte disturbances, renal function, and acid-base status 5
• Hyponatremia is the most common electrolyte disturbance precipitating seizures 6
• Pregnancy test in women of childbearing age 5, 6
• Antiepileptic drug levels in patients with known epilepsy to assess non-compliance 5
• Toxicology screening if substance use, withdrawal, or overdose suspected 5

Additional Testing Based on Clinical Presentation

• Arterial blood gas if respiratory compromise or metabolic acidosis suspected 5
• Lumbar puncture if meningitis or encephalitis suspected (fever with meningeal signs, immunocompromised status) 5, 6
• Emergent EEG if persistent altered consciousness to detect non-convulsive status epilepticus—occurs in 25% of patients with generalized convulsive SE 1

Neuroimaging Strategy

Emergent Non-Contrast Head CT Indications

Perform emergent head CT without contrast when any high-risk feature is present: 6

• Age >40 years 6
• Recent head trauma 6
• Focal seizure onset before generalization 6
• Fever or persistent headache 6
• Anticoagulation use 6
• Known malignancy or immunocompromised state 6
• Focal neurologic deficit 6
• Persistent altered mental status 6

CT abnormalities are identified in 23-41% of first-time seizure presentations. 6

Deferred Outpatient MRI

If patient has returned to baseline, normal neurologic exam, no high-risk features, and reliable outpatient follow-up, neuroimaging can be deferred to outpatient MRI—MRI is more sensitive for epileptogenic lesions in temporal and orbitofrontal regions. 6

Disposition Criteria

Safe for Discharge

Patients who have returned to their clinical baseline in the ED can be safely discharged without admission. 6

• Arrange outpatient EEG—abnormal EEG predicts higher seizure recurrence risk 6
• Ensure reliable follow-up arrangements 6

Admission Criteria

• Persistent abnormal neurologic examination 6
• Abnormal investigation results requiring inpatient management 6
• Failure to return to baseline 6
• Unreliable follow-up or social concerns 6

Critical Pitfalls to Avoid

• Never use neuromuscular blockers alone (e.g., rocuronium)—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 delay benzodiazepine administration for glucose testing—causes 2.1-5.9 minute delay without benefit 2
• Maintain continuous EEG monitoring throughout tapering of anesthetic agents and for 24-48 hours after discontinuation—breakthrough seizures occur in >50% and are often only detectable by EEG 1
• Avoid attributing altered mental status solely to post-ictal state—obtain urgent EEG if patient does not awaken within expected timeframe, as non-convulsive SE occurs in >50% of cases 1

Prognosis

• Overall mortality for status epilepticus ranges from 5-22% 1
• In refractory cases, mortality can reach 65% 1