Emergency and Follow-Up Management of Seizures
Immediate Management of Active Seizure (0-5 Minutes)
Administer intravenous lorazepam 4 mg at 2 mg/min immediately for any patient actively seizing—this terminates status epilepticus in 65% of cases and is superior to diazepam (59.1% vs 42.6% efficacy). 1
Critical First Steps
- Check fingerstick glucose immediately and correct hypoglycemia while administering lorazepam, as this is a rapidly reversible cause of seizures. 1
- Have airway equipment immediately available before giving any benzodiazepine due to respiratory depression risk—ventilatory support must be readily accessible. 2, 3
- Establish IV access and start fluid resuscitation simultaneously with benzodiazepine administration to maintain euvolemia and prevent hypotension. 1
- Monitor vital signs continuously, particularly respiratory status and blood pressure, and be prepared to provide respiratory support. 1
Status Epilepticus Definition
- Treat any seizure lasting ≥5 minutes as status epilepticus—seizures persisting this long are unlikely to stop spontaneously and require immediate intervention. 1, 4
- The operational definition has shifted from 30 minutes to 5 minutes because delayed treatment significantly increases morbidity and mortality risk (5-22% overall, up to 65% in refractory cases). 2, 1
Second-Line Treatment (5-20 Minutes After Benzodiazepines)
If seizures persist after adequate benzodiazepine dosing, immediately escalate to a second-line anticonvulsant—do not delay for neuroimaging. 1
Preferred Second-Line Agents (Ordered by Safety Profile)
Valproate is the preferred second-line agent with 88% efficacy and 0% hypotension risk, making it safer than alternatives. 1
Valproate 20-30 mg/kg IV (maximum 3000 mg) over 5-20 minutes: 88% seizure cessation rate with no hypotension risk, superior safety profile compared to phenytoin. 1
Levetiracetam 30 mg/kg IV (maximum 2500-3000 mg) over 5 minutes: 68-73% efficacy with minimal cardiovascular effects (≈0.7% hypotension risk), no cardiac monitoring required. 1
Fosphenytoin 20 mg PE/kg IV at ≤150 PE/min: 84% efficacy but 12% hypotension risk requiring continuous ECG and blood pressure monitoring. 1
Phenobarbital 20 mg/kg IV over 10 minutes: 58.2% efficacy as initial second-line agent but higher risk of respiratory depression and hypotension. 1
Critical Pitfall to Avoid
- Never skip directly to third-line anesthetic agents (midazolam, propofol, pentobarbital) until benzodiazepines and one second-line agent have been tried. 1
- Do not use neuromuscular blockers alone (e.g., rocuronium)—they only mask motor manifestations while allowing continued electrical seizure activity and brain injury. 1
Refractory Status Epilepticus (20+ Minutes)
Refractory status epilepticus is defined as seizures continuing despite benzodiazepines and one second-line agent—initiate continuous EEG monitoring at this stage. 1
Third-Line Anesthetic Agents
Midazolam infusion is the first-choice anesthetic agent with 80% efficacy and lower hypotension risk (30%) compared to barbiturates (77%). 1
Midazolam: Loading dose 0.15-0.20 mg/kg IV, then continuous infusion 1 mg/kg/min, titrate up by 1 mg/kg/min every 15 minutes to maximum 5 mg/kg/min. 1
- Load with a long-acting anticonvulsant (phenytoin/fosphenytoin, valproate, levetiracetam, or phenobarbital) during the midazolam infusion before tapering to ensure adequate anticonvulsant coverage. 1
Propofol: 2 mg/kg bolus, then 3-7 mg/kg/hour infusion—73% efficacy with 42% hypotension risk. 1
Pentobarbital: 13 mg/kg bolus, then 2-3 mg/kg/hour infusion—highest efficacy at 92% but 77% hypotension risk requiring vasopressors. 1
EEG Monitoring Requirements
- Continuous EEG should guide titration to achieve seizure suppression and detect ongoing electrical seizure activity without motor manifestations. 1
- Maintain continuous EEG throughout tapering and for 24-48 hours after discontinuation—breakthrough seizures occur in >50% of patients and are often only detectable by EEG. 1
- About 25% of patients with generalized convulsive status epilepticus have ongoing non-convulsive electrical seizures, requiring sustained EEG monitoring. 1
Simultaneous Evaluation for Underlying Causes
While administering anticonvulsants, immediately search for and treat reversible causes—do not delay treatment to obtain neuroimaging. 1
Reversible Causes to Identify and Correct
- Hypoglycemia: Check fingerstick glucose immediately. 1
- Hyponatremia: Most common electrolyte abnormality causing seizures. 2, 6
- Hypoxia: Ensure adequate oxygenation. 1
- Drug toxicity or withdrawal: Alcohol, benzodiazepines, barbiturates. 1, 6
- CNS infection: Meningitis, encephalitis. 1
- Acute stroke or intracerebral hemorrhage: Particularly in patients >40 years. 2
- Metabolic derangements: Hypocalcemia, hypomagnesemia, uremia. 6
New-Onset Seizure: Emergency Department Work-Up
For patients who have returned to baseline neurologic status after a first-time seizure, obtain serum glucose and sodium—these are the only laboratory tests that consistently alter acute ED management. 7
Laboratory Evaluation
- Serum glucose and sodium: Most frequent abnormalities identified; hypoglycemia and hyponatremia require immediate intervention. 2, 7
- Pregnancy test: If patient is of childbearing age. 2, 7
- Additional labs only when clinically indicated: Complete metabolic panel, calcium, magnesium only if specific clinical clues present (vomiting, diarrhea, dehydration, known cancer, renal failure). 7
- Lumbar puncture: Reserved for suspected meningitis/encephalitis (fever with meningeal signs) or immunocompromised patients (after head CT to rule out mass effect). 2, 7
Neuroimaging Strategy
Perform emergent non-contrast head CT when any high-risk feature is present—CT abnormalities are found in 23-41% of first-time seizure presentations. 7
High-Risk Features Requiring Emergent CT
- Age >40 years 2, 7
- Recent head trauma 2, 7
- Focal seizure onset before generalization 2, 7
- Fever or persistent headache 2, 7
- Anticoagulation use 2, 7
- History of malignancy or immunocompromised state 2, 7
- Focal neurologic deficits or persistent altered mental status 2, 7
- Failure to return to baseline within several hours 7
Deferred Outpatient MRI
If the patient has returned to baseline, normal neurologic exam, no high-risk features, and reliable follow-up, neuroimaging may be deferred to outpatient MRI. 2, 7
- MRI is the preferred modality for non-emergent evaluation because it is more sensitive than CT for epileptogenic lesions, especially in temporal and orbitofrontal lobes. 7
Electroencephalography (EEG)
- Arrange an EEG (outpatient acceptable) as part of the neurodiagnostic work-up for every patient with an apparent first unprovoked seizure—abnormal EEG findings predict higher seizure recurrence risk. 7
- Emergent EEG is indicated for persistent altered consciousness after seizure to detect nonconvulsive status epilepticus. 7
Disposition Decisions
Patients who have returned to their clinical baseline in the ED can be safely discharged without admission. 2, 7
Admission Criteria
- Persistent abnormal neurologic examination 2, 7
- Abnormal investigation results requiring inpatient management 2, 7
- Patient has not returned to baseline 2, 7
- Unreliable follow-up or social concerns 2
Seizure Recurrence Risk
- The mean time to first seizure recurrence is 121 minutes (median 90 minutes), with >85% of early recurrences occurring within 6 hours of ED presentation. 7
- Overall 24-hour recurrence rate is 19%, decreasing to 9% when alcohol-related events and focal CT lesions are excluded. 7
- Nonalcoholic patients with new-onset seizures have the lowest recurrence rate (9.4%), while alcoholic patients with seizure history have the highest (25.2%). 7
- Approximately 30-50% of patients experience seizure recurrence within five years after a first unprovoked seizure. 7
Antiepileptic Drug (AED) Initiation After First Seizure
Do not start an AED in the ED for provoked seizures or for a first unprovoked seizure when no evidence of prior brain disease or injury exists. 7
When to Consider AED Initiation
- Consider initiating an AED only when the first unprovoked seizure occurs in the setting of remote symptomatic brain disease or injury (e.g., prior stroke >7 days ago, traumatic brain injury, tumor, chronic CNS disease). 7
- Starting AED therapy after the first seizure prolongs the interval to the next event but does not improve five-year outcomes—the number needed to treat to prevent one seizure recurrence within two years is 14 patients. 7
- Patients with remote symptomatic seizures have higher recurrence rates, supporting early AED initiation after a single event. 7
Follow-Up Management for Established Epilepsy
For patients with established epilepsy on antiepileptic drugs, continue current therapy and investigate causes of breakthrough seizures. 5
Causes of Breakthrough Seizures
- Non-compliance: Most common cause—verify medication compliance by checking serum drug levels. 5
- Sleep deprivation, alcohol use, intercurrent illness: Common precipitating factors. 1
- Drug interactions: Particularly with enzyme-inducing anticonvulsants (phenytoin, carbamazepine, phenobarbital). 5
Medication Optimization
- Optimize current AED dosing before adding another agent—ensure adequate serum levels and compliance first. 5
- If seizures remain uncontrolled on adequate monotherapy, consider adding valproate, levetiracetam, or lamotrigine as adjunctive therapy. 5
- Avoid valproate in women of childbearing potential due to significantly increased risks of fetal malformations and neurodevelopmental delay. 5
Common Pitfalls to Avoid
- Approximately 28-48% of suspected first seizures have alternative diagnoses (syncope, nonepileptic seizures, panic attacks)—careful history is essential. 7
- Alcohol withdrawal seizures should be a diagnosis of exclusion, especially in first-time seizures—always search for symptomatic causes. 7
- Do not attribute altered mental status solely to post-ictal state—obtain urgent EEG if patient does not awaken within expected timeframe, as nonconvulsive status epilepticus occurs in >50% of cases. 1
- Phenytoin is ineffective for seizures secondary to alcohol withdrawal, theophylline toxicity, or isoniazid toxicity. 6
- Most ill patients with secondary seizures do not have epilepsy—only those with recurrent seizures and uncorrectable predisposing factors need long-term AED treatment. 6