Status epilepticus (SE) is a neurological emergency defined as a seizure lasting ≥5 minutes for generalized tonic-clonic seizures, ≥10 minutes for focal SE with impaired awareness, or ≥10–15 minutes for absence SE. [1-2] It affects an estimated 10–41 per 100,000 population annually, with overall mortality approaching 20% in adults. [3] Prompt recognition and aggressive stepwise treatment are critical to reducing morbidity and mortality.
1. History
- Duration of seizure activity and time of onset — critical for treatment staging
- Witnessed vs. unwitnessed; description of motor activity (tonic, clonic, focal onset)
- Number of seizures and whether consciousness was regained between episodes
- Known epilepsy diagnosis and current antiseizure medications (ASMs) — subtherapeutic ASM levels are the most common trigger in known epileptics (low levels found in 32% when checked) [4]
- Recent medication changes, missed doses, or new medications
- Recent illness, fever, sleep deprivation
- Alcohol or substance use history (withdrawal is a common precipitant) [2]
- History of head trauma, stroke, CNS infection, or brain tumor
- Pregnancy status
- Pre-hospital treatments already administered (benzodiazepine type, dose, route, timing) — essential to avoid underdosing or unnecessary delays [2]
2. Alarm Features
- Seizure duration >5 minutes without termination
- Failure to regain consciousness between seizures
- Focal neurological deficits suggesting acute structural pathology (stroke, hemorrhage, mass)
- Fever with seizure → concern for CNS infection (meningitis, encephalitis)
- Signs of elevated intracranial pressure (papilledema, Cushing triad)
- Respiratory compromise: apnea, cyanosis, oxygen desaturation
- Hemodynamic instability
- Progression from convulsive to subtle/nonconvulsive SE (cessation of motor activity with persistent altered consciousness) — carries worse prognosis [5]
- New-onset refractory SE (NORSE) without identifiable cause → consider autoimmune encephalitis [2]
3. Medications
First-line (Emergent phase, 0–5 min):
- Lorazepam 0.1 mg/kg IV (max 4 mg/dose), may repeat once after 5–10 min [6]
- Midazolam 10 mg IM (≥40 kg) or 0.2 mg/kg IV — IM midazolam is non-inferior to IV lorazepam and preferred when no IV access [7-8]
- Diazepam 0.15–0.2 mg/kg IV (max 10 mg) or 0.5 mg/kg PR [9-10]
Second-line (Established SE, 5–30 min):
- Fosphenytoin 20 mg PE/kg IV (preferred over phenytoin; faster infusion, less tissue injury) [3]
- Levetiracetam 60 mg/kg IV (max 4500 mg)
- Valproic acid 40 mg/kg IV (max 3000 mg)
- Lacosamide — found non-inferior to fosphenytoin in the TRENdS trial [2]
- The ESETT trial showed no difference in efficacy among fosphenytoin, levetiracetam, and valproic acid; all effective in <50% of established SE [2][7][10]
Third-line (Refractory SE):
- Continuous infusions of midazolam, propofol, or pentobarbital — requires intubation and ICU admission [11-12]
- Ketamine increasingly used, has antiseizure properties and can be used during RSI [2]
Medications to avoid/use with caution:
- Phenytoin/fosphenytoin: risk of hypotension and arrhythmia; contraindicated in second/third-degree heart block [3][13]
- Valproic acid: avoid in pregnancy, hepatic failure, mitochondrial disease, pancreatitis
- Propofol: risk of propofol infusion syndrome with prolonged use
- Neuromuscular blockers mask clinical seizure activity — use short-acting agents only if intubation required [3]
Common underdosing pitfall: A convenient dose of phenytoin 1000 mg IV is often insufficient — dosing is weight-based at 20 mg/kg. [3] Similarly, lorazepam is frequently underdosed; doses <4 mg are associated with significantly higher rates of progression to refractory SE (87% vs. 62%). [14]
4. Diet
- NPO during active SE and until airway is secured and mental status returns to baseline
- Glucose: check immediately — hypoglycemia is a reversible cause; administer dextrose if low
- Thiamine: give up to 500 mg IV before or concurrent with glucose to prevent Wernicke encephalopathy [3]
- Ketogenic diet may be considered in super-refractory SE as adjunctive therapy in the ICU setting
5. Review of Systems
- Neurologic: headache, focal weakness, vision changes, confusion, prior seizures
- Infectious: fever, neck stiffness, rash, recent illness, immunocompromised state
- Metabolic: polyuria/polydipsia (hypo/hyperglycemia), renal disease symptoms
- Toxicologic: substance use, medication ingestion, withdrawal symptoms
- Cardiovascular: palpitations, chest pain (cardiac injury occurs in SE) [15]
- Obstetric: pregnancy status (eclampsia)
6. Collateral History and Family History
- Collateral from witnesses/EMS is essential: seizure description, timing, pre-hospital medications given, baseline mental status
- Prior seizure history, epilepsy diagnosis, current ASMs and compliance
- Recent hospitalizations, surgeries, or procedures
- Family history of epilepsy, febrile seizures, or sudden unexplained death
- Social context: substance use, housing stability (medication access), caregiver availability
7. Risk Factors
- Known epilepsy with subtherapeutic ASM levels (most common cause in chronic epilepsy) [3-4]
- Acute CNS pathology: stroke (most common acute symptomatic cause in adults), CNS infection, traumatic brain injury [3][16]
- Alcohol or benzodiazepine withdrawal [2]
- Metabolic derangements: hyponatremia, hypoglycemia, hypocalcemia, uremia, hepatic failure
- Remote structural brain lesions (prior stroke, tumor, TBI) [2]
- Autoimmune encephalitis (especially anti-NMDA receptor, anti-LGI1) [2]
- Age: bimodal distribution — highest incidence in children <1 year (51/100,000) and adults >60 years (up to 68.5/100,000 in those >80) [2]
- Male sex (higher incidence), African American race (higher incidence) [2]
- Herpes simplex encephalitis (HR 5.5 for SE), progressive MS, intracerebral hemorrhage [17]
- Neurotoxic medications: cephalosporins, ifosfamide, methotrexate, baclofen, lithium, opioids [2]
8. Differential Diagnosis
- Psychogenic non-epileptic seizures (PNES/functional seizures) — most important mimic; look for asynchronous movements, eye closure, preserved awareness, prolonged duration without postictal state; serum prolactin (drawn within 20 min) has 53% sensitivity and 93% specificity for true epileptic seizures [2]
- Convulsive syncope — brief myoclonic jerks with syncope, rapid recovery
- Movement disorders: dystonia, myoclonus, tremor [2]
- Rigors from sepsis or drug reactions
- Eclampsia in pregnant/postpartum patients
- Decerebrate/decorticate posturing from brainstem pathology
- Nonconvulsive SE presenting as unexplained altered mental status — requires EEG for diagnosis [18]
- Serotonin syndrome or neuroleptic malignant syndrome
- Toxic ingestion (sympathomimetics, anticholinergics, isoniazid, organophosphates)
9. Past Medical History
- Prior seizures or epilepsy diagnosis — 54% of SE cases occur without a prior epilepsy diagnosis [3]
- Prior episodes of SE (risk of recurrence)
- Stroke, TBI, brain tumor, CNS surgery
- HIV/immunocompromised state (opportunistic CNS infections)
- Autoimmune conditions
- Hepatic or renal disease (affects ASM metabolism and dosing)
- Cardiac history (relevant for phenytoin/fosphenytoin use)
- Psychiatric history and current psychotropic medications
10. Physical Exam
Vital signs:
- Tachycardia, hypertension (sympathetic surge during convulsive SE)
- Hyperthermia — can occur from prolonged motor activity; also raises concern for infection
- Hypoxia, apnea
Focused exam:
- Airway: patency, secretions, tongue laceration
- Neurologic: level of consciousness, pupil size/reactivity, focal deficits (Todd paralysis vs. structural lesion), subtle motor signs (eye deviation, nystagmus, facial twitching, finger/hand automatisms) suggesting ongoing nonconvulsive SE [18]
- Head/neck: signs of trauma, meningismus
- Skin: needle tracks, rash (meningococcemia), cyanosis
- Fundoscopic: papilledema (elevated ICP)
- Oral: tongue bite (lateral bite highly specific for epileptic seizure)
11. Lab Studies
Immediate:
- Point-of-care glucose (before anything else)
- BMP: sodium, calcium, magnesium, glucose, BUN/creatinine
- CBC
- ASM levels in known epileptics (low in 32% of cases) [4]
- Pregnancy test in patients of childbearing potential [2]
Additional:
- ABG/VBG with lactate (metabolic acidosis common; usually self-corrects) [3]
- Hepatic function panel
- Troponin — cardiac injury markers are common in refractory SE (abnormal in ~26% when checked) [15]
- CK (rhabdomyolysis risk)
- Toxicology screen (urine and serum)
- Prolactin (if drawn within 20 min of event, 93% specificity for epileptic seizure vs. PNES) [2]
- Blood and urine cultures if infection suspected
- Lumbar puncture if meningitis/encephalitis suspected (after CT to rule out mass/herniation risk); CSF pleocytosis should not be attributed to seizures alone — always investigate further [2]
12. Imaging
First-line:
- CT head without contrastLancet Neurol[2]
Gold standard:
When imaging may be deferred:
Important findings:
- Acute stroke, hemorrhage, mass lesion, abscess
- Mesial temporal sclerosis
- Cortical restricted diffusion (peri-ictal changes)
- Leptomeningeal enhancement (infection, carcinomatosis)
13. Special Tests
Scoring systems:
- Status Epilepticus Severity Score (STESS): uses consciousness level, seizure type, age, and seizure history at presentation; reliable negative predictive value for mortality [3]
- Epidemiology-based Mortality Score in SE (EMSE)
Point-of-care:
- Bedside glucose
- Bedside ultrasound (cardiac function if hemodynamically unstable)
Procedures:
- Lumbar puncture — indicated for suspected CNS infection, autoimmune encephalitis, or unknown etiology [2]
- Continuous EEG monitoring — essential for refractory/super-refractory SE management and for detecting nonconvulsive seizures (approximately half of patients with persistent altered consciousness after SE have ongoing nonconvulsive seizures on EEG) [2]
Autoimmune workup (in refractory/cryptogenic cases):
14. ECG
- ECG should be obtained in all SE patients — early ECG abnormalities are found in 93.5% of critically ill SE patients [20]
- Common findings: sinus tachycardia (65.7%), T-wave inversions (42.1%), ST elevation (16.6%), ST depression (17.9%), QTc prolongation (22.9%) [15][20]
- Arrhythmias: atrial fibrillation/flutter (20%), sinus bradycardia (48.6%), ventricular tachycardia/fibrillation (11.4%) [15]
- Phenytoin/fosphenytoin can cause bradycardia, AV block, and hypotension during infusion — requires cardiac monitoring [13][21]
- Lacosamide associated with PR prolongation; use with caution in patients with cardiac conduction disease [22]
- Consider troponin and echocardiography if repolarization abnormalities are present [15]
15. Assessment
Severity stratification:
- Early SE: seizure >5 min, responsive to first-line benzodiazepines (~65% terminate with lorazepam) [3]
- Established SE: persists after adequate benzodiazepine dosing; second-line agents effective in <50% [7]
- Refractory SE (RSE): persists after first- and second-line agents; occurs in 14–46% of SE cases; mortality ~25% [11][23]
- Super-refractory SE: continues ≥24 hours after anesthetic initiation or recurs on weaning; mortality ~40% [11]
Key prognostic determinants: Etiology is the most important predictor of mortality. Acute primary CNS pathology (e.g., CNS infection, stroke) carries the highest mortality, while SE from subtherapeutic ASM levels carries the lowest. [2-3]
Complications:
- Neuronal injury (excitotoxicity from prolonged seizure activity)
- Aspiration pneumonia
- Rhabdomyolysis and acute kidney injury
- Cardiac injury and arrhythmias [15]
- Metabolic acidosis (usually self-correcting) [3]
- Hyperthermia
- Cerebral edema
16. Treatment Plan
Phase 1 — Stabilization (0–5 min):
- ABCs: position, suction, supplemental O₂, monitor SpO₂
- IV access (two large-bore IVs); IO if IV not obtainable
- Check glucose → give dextrose if hypoglycemic
- Thiamine 500 mg IV before/with glucose [3]
- Cardiac monitor, continuous pulse oximetry
Phase 2 — First-line (0–10 min):
- Lorazepam 4 mg IV (0.1 mg/kg), may repeat ×1 after 5 min; OR
- Midazolam 10 mg IM if no IV access [6-7][10]
- Account for pre-hospital doses
Phase 3 — Second-line (10–30 min):
- If seizures persist after adequate benzodiazepine dosing:
- Fosphenytoin 20 mg PE/kg IV (infuse at 150 mg PE/min) with cardiac monitoring; OR
- Levetiracetam 60 mg/kg IV (max 4500 mg, infuse over 15 min); OR
- Valproic acid 40 mg/kg IV (max 3000 mg, infuse over 10 min) [2][10]
- Choice should be individualized based on comorbidities and contraindications
Phase 4 — Third-line/Refractory SE (>30 min):
- Prepare for intubation (use short-acting paralytic; ketamine or propofol for induction given antiseizure properties) [2]
- Continuous infusion: midazolam (0.2 mg/kg bolus, then 0.1–2 mg/kg/hr), propofol (1–2 mg/kg bolus, then 20–65 mcg/kg/min), or pentobarbital (5–15 mg/kg load, then 0.5–5 mg/kg/hr) [11-12]
- Titrate to EEG-confirmed seizure suppression or burst-suppression for ≥24–48 hours [24]
- ICU admission with continuous video-EEG monitoring [11]
Parallel actions at all stages:
- Identify and treat the underlying cause [1-2]
- Consider empiric antibiotics/antivirals if CNS infection suspected
- Consider immunotherapy if autoimmune etiology suspected [1]
The following figure illustrates a stepwise management algorithm for prolonged seizures and SE:
17. Disposition
All patients with SE require admission:
- ICU admission: refractory SE, need for intubation/anesthetic infusions, hemodynamic instability, respiratory compromise, super-refractory SE [2][11]
- Monitored bed/step-down: SE that terminates with first- or second-line agents but requires observation, EEG monitoring, or etiologic workup
- Neurology consultation: all cases of SE
- Neurocritical care consultation: refractory and super-refractory SE
- Additional consultations: infectious disease (if CNS infection), neurosurgery (if mass lesion/hemorrhage), toxicology (if ingestion), OB/GYN (if eclampsia)
Discharge is not appropriate from the ED for any patient with SE. Even patients whose seizures terminate rapidly require monitoring for recurrence, etiologic workup, and medication optimization.
18. Follow Up / Return Precautions
After hospitalization:
- Neurology follow-up within 1–2 weeks of discharge
- ASM level monitoring and dose optimization
- Outpatient EEG if not completed during admission
- MRI brain if not obtained during hospitalization
- Driving restrictions per local regulations
- Seizure action plan for patient and caregivers, including rescue medications (e.g., intranasal midazolam, rectal diazepam, buccal midazolam)
Return precautions (for patients/caregivers):
- Seizure lasting >5 minutes or recurrent seizures without recovery → call 911
- New focal weakness, speech difficulty, severe headache
- Fever with seizure
- Failure to return to baseline mental status
- Medication side effects (rash, severe dizziness, palpitations)
Expected course: Mortality is 10–15% overall, rising to 25% in refractory and ~40% in super-refractory SE. [11] SE confers a 3.3× increased risk of future unprovoked seizures compared with a single symptomatic seizure. [3] Long-term cognitive and functional outcomes depend heavily on the underlying etiology and duration of SE.
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