Status Epilepticus in Adults

Topic Overview

Summary

Status epilepticus (SE) is a neurological emergency defined as continuous seizure activity lasting ≥5 minutes or recurrent seizures without recovery of consciousness between episodes. [1,2] It represents a failure of the mechanisms responsible for seizure termination and has significant morbidity and mortality. Early recognition and immediate treatment are critical, as neuronal damage increases with seizure duration beyond 30 minutes. [3] The overall mortality rate is 10-20%, rising to 30-40% in refractory cases. [4]

First-line treatment is intravenous benzodiazepines (lorazepam or midazolam), followed by second-line anti-seizure medications (levetiracetam, phenytoin, or valproate) if seizures persist beyond 10-20 minutes. [5,6] Refractory status epilepticus requires intensive care management with general anaesthesia and continuous EEG monitoring. [7] Identifying and treating the underlying cause is essential for optimal outcomes.

Key Facts

• Definition: Continuous seizure activity ≥5 minutes OR ≥2 seizures without regaining consciousness
• Incidence: 10-40 per 100,000 population per year; bimodal distribution (young children and elderly)
• Mortality: 10-20% overall; 30-40% in refractory SE; higher in anoxic and infectious aetiologies [4]
• First-line: Lorazepam 4mg IV (0.1mg/kg) or midazolam 10mg IM/buccal [8]
• Second-line: Levetiracetam 60mg/kg IV, phenytoin 20mg/kg IV, or valproate 40mg/kg IV [6]
• Third-line: General anaesthesia with propofol, midazolam, or thiopentone in ICU setting [7]
• Critical timing: Seizure termination within 30 minutes minimises neuronal injury [3]

Clinical Pearls

"Time is brain" — Neuronal damage increases exponentially with seizure duration. Irreversible hippocampal injury begins after 30 minutes of continuous seizure activity.

GABA receptor internalisation — Prolonged seizures cause GABA-A receptors to move from the cell surface into the cytoplasm, making benzodiazepines progressively less effective. This explains why early treatment is crucial and why delayed benzodiazepine administration has reduced efficacy.

Midazolam is non-inferior to lorazepam — The RAMPART trial demonstrated that intramuscular midazolam is as effective as IV lorazepam for pre-hospital treatment, with the advantage of not requiring IV access. [8]

Non-convulsive status epilepticus (NCSE) — Always consider NCSE in patients with unexplained altered consciousness, especially following convulsive SE. Up to 20% of patients in coma have NCSE on EEG. [9]

Second-line agents are equally effective — The ESETT trial showed levetiracetam, fosphenytoin, and valproate have similar efficacy (approximately 45-50% seizure cessation) when used as second-line therapy. [6] Choice should be guided by patient factors (pregnancy, liver disease, haemodynamic stability).

Why This Matters Clinically

Status epilepticus is a medical emergency that requires immediate recognition and treatment. Delayed intervention leads to:

• Neuronal injury: Excitotoxic cell death, hippocampal sclerosis, and permanent cognitive impairment
• Systemic complications: Aspiration pneumonia, rhabdomyolysis, acute kidney injury, hyperthermia, cardiovascular collapse
• Treatment resistance: GABA-A receptor trafficking makes prolonged seizures increasingly refractory to benzodiazepines
• Mortality: Overall 10-20%, but approaches 40% in refractory cases and elderly patients [4]

Every clinician must know the time-based treatment protocol and be prepared to escalate therapy rapidly through the treatment stages.

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Visual Summary

Visual assets to be added:

• Status epilepticus treatment algorithm (time-based protocol with 0-5 min, 5-10 min, 10-20 min, 20-40 min stages)
• Benzodiazepine dosing chart (lorazepam, midazolam, diazepam routes and doses)
• GABA receptor trafficking diagram (mechanism of benzodiazepine resistance)
• Causes of status epilepticus infographic (known epilepsy, alcohol withdrawal, stroke, infection, metabolic)
• EEG patterns in status epilepticus (convulsive vs non-convulsive patterns)
• Neuropathological timeline (neuronal injury progression at 5, 30, 60 minutes)

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Epidemiology

Incidence and Prevalence

Status epilepticus affects 10-40 per 100,000 individuals per year in developed countries, with higher rates in resource-limited settings. [1,10] The incidence follows a bimodal age distribution:

• First peak: Children less than 1 year (highest incidence)
• Second peak: Adults > 60 years

In the United States, an estimated 150,000-200,000 cases occur annually. [10]

Demographics

Age:

• Children account for approximately 50% of cases
• Elderly (> 60 years) represent 30-40% of cases and have higher mortality
• Mean age at presentation: 40-50 years for convulsive SE

Sex:

• Slight male predominance (1.2-1.5:1 male:female ratio)

Socioeconomic factors:

• Higher incidence in lower socioeconomic groups
• Alcohol-related SE more common in urban populations

Mortality and Morbidity

Mortality rates: [4,11]

• Overall: 10-20%
• Refractory SE: 30-40%
• Super-refractory SE: 40-50%
• Anoxic SE: 60-80%
• Age > 65 years: 20-30%

Prognostic factorsifying mortality**:

• Aetiology (anoxic > infectious > symptomatic acute > remote symptomatic)
• Duration of status epilepticus (> 60 min worse)
• Age (elderly worse)
• Number of anti-seizure medications required
• Presence of comorbidities (cardiovascular, renal, hepatic disease)

Long-term morbidity:

• 10-20% develop new neurological deficits
• Cognitive impairment in 20-30% of survivors
• Development of new-onset epilepsy in 15-25%
• Hippocampal sclerosis leading to temporal lobe epilepsy

Aetiology

The causes of status epilepticus vary by age and geographical region:

Special populations:

• Pregnancy: Eclampsia, pre-eclampsia, posterior reversible encephalopathy syndrome (PRES)
• Elderly: Stroke and metabolic causes predominate
• Children: Febrile SE, genetic epilepsies, infections

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Pathophysiology

Normal Seizure Termination Mechanisms

Under normal circumstances, seizures are self-limiting due to:

• GABA-mediated inhibition: GABA-A receptors increase chloride conductance, hyperpolarising neurons
• Potassium currents: Calcium-activated potassium channels repolarise neurons
• Adenosine release: Inhibitory neuromodulator accumulation
• Synaptic vesicle depletion: Limits glutamate release

Failure of Seizure Termination

Status epilepticus represents a failure of these termination mechanisms:

GABA-A receptor trafficking: [12]

• During prolonged seizures, GABA-A receptors undergo clathrin-mediated endocytosis
• Receptors are internalised from the cell membrane into the cytoplasm
• Surface GABA-A receptor density decreases by 40-60% after 30-60 minutes
• This reduces benzodiazepine efficacy and contributes to pharmacoresistance

NMDA receptor upregulation: [13]

• Glutamate NMDA receptors are trafficked to the cell surface
• Increased excitatory neurotransmission
• Enhanced calcium influx leading to excitotoxicity

Temporal Phases of Status Epilepticus

Status epilepticus evolves through distinct pathophysiological phases:

Phase 1: Compensated (0-30 minutes)

• Maintained cerebral blood flow and oxygenation
• Catecholamine surge (tachycardia, hypertension, hyperglycaemia)
• Lactate production but adequate ATP generation
• GABA-A receptors still responsive to benzodiazepines
• Minimal permanent neuronal injury if seizure terminated

Phase 2: Early decompensation (30-60 minutes)

• Cerebral metabolic demand exceeds supply
• Lactate accumulation, intracellular acidosis
• Blood pressure declines, hypoxia develops
• NMDA receptor-mediated calcium influx
• Onset of excitotoxic neuronal injury (especially hippocampus, amygdala, thalamus)
• GABA-A receptor internalisation reducing benzodiazepine efficacy

Phase 3: Decompensation (> 60 minutes)

• Failure of homeostatic mechanisms
• Hypotension, hyperthermia (> 40°C), hypoglycaemia
• Rhabdomyolysis, myoglobinaemia, acute kidney injury
• Disseminated intravascular coagulation (DIC)
• Irreversible neuronal death (hippocampal sclerosis, cortical laminar necrosis)
• Multi-organ failure

Molecular Mechanisms of Neuronal Injury

Excitotoxicity:

• Excessive glutamate release activates NMDA and AMPA receptors
• Calcium influx triggers mitochondrial dysfunction
• Generation of reactive oxygen species (ROS)
• Activation of proteases (calpains) and endonucleases
• Apoptotic and necrotic cell death pathways

Inflammation:

• Microglial activation and cytokine release (IL-1β, IL-6, TNF-α)
• Blood-brain barrier breakdown
• Infiltration of peripheral immune cells
• Contributes to ongoing seizures and neuronal damage

Mitochondrial dysfunction:

• ATP depletion despite increased metabolic demand
• Mitochondrial membrane permeabilisation
• Release of cytochrome c and activation of apoptosis

Long-term Consequences

Hippocampal sclerosis:

• Selective neuronal loss in CA1, CA3, dentate gyrus
• Gliosis and synaptic reorganisation
• Development of mesial temporal lobe epilepsy

Cognitive impairment:

• Memory deficits (hippocampal injury)
• Executive dysfunction (frontal lobe damage)
• Processing speed reduction

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Clinical Presentation

Classification of Status Epilepticus

By semiology (clinical manifestations):

1. Convulsive Status Epilepticus (CSE)

• Generalised convulsive SE: Continuous or intermittent generalised tonic-clonic activity
• Focal motor SE: Continuous focal motor activity (face, limb)
  • "Epilepsia partialis continua: Continuous focal myoclonic jerking with preserved consciousness"

2. Non-Convulsive Status Epilepticus (NCSE)

• Absence status: Generalised spike-wave on EEG, clouded consciousness
• Complex partial status: Altered awareness, automatisms, focal EEG changes
• Subtle status: Minimal motor manifestations after prolonged convulsive SE

Convulsive Status Epilepticus

Clinical features:

• Continuous tonic-clonic movements (jerking of limbs, body stiffening)
• Loss of consciousness (GCS 3-8)
• Eyes may be open or deviated
• Frothing at mouth, excessive salivation
• Cyanosis (if airway compromised)
• Urinary or faecal incontinence
• Tongue biting (lateral tongue is specific for true seizure)

Evolution:

• Initial tonic-clonic activity may become less pronounced over time
• "Subtle SE": Minimal motor activity (eye deviation, nystagmus, subtle facial twitching) after 30-60 minutes of convulsive SE
• Ongoing electrical seizure activity on EEG despite reduced motor manifestations

Non-Convulsive Status Epilepticus (NCSE)

Clinical features: [9]

• Altered level of consciousness (confusion, somnolence, stupor, coma)
• Fluctuating mental status
• Behavioural changes (agitation, aggression, withdrawal)
• Subtle motor signs may be present:
  • Eye deviation or nystagmus
  • Facial twitching
  • Automatisms (lip smacking, chewing, picking movements)

High-risk populations for NCSE:

• ICU patients with unexplained altered consciousness
• Following cessation of convulsive SE
• Elderly with acute confusion
• Post-cardiac arrest (20-40% have NCSE) [9]

Diagnosis:

• Requires EEG confirmation
• EEG shows continuous or nearly continuous epileptiform activity

Focal Motor Status Epilepticus

Epilepsia partialis continua (EPC):

• Continuous focal motor seizures involving face or limbs
• Consciousness typically preserved
• Can persist for days to weeks
• Often refractory to treatment
• Associated with focal structural lesions (stroke, tumour, cortical dysplasia)

Red Flags Indicating High Risk

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Clinical Examination

Initial Assessment (ABCDE Approach)

Airway:

• Patent? Look for obstruction by tongue, secretions, vomit
• Position patient in recovery position (left lateral) if no spinal injury concern
• Suction if secretions present
• Do NOT insert anything into the mouth (risk of injury, aspiration)
• Do NOT restrain the patient

Breathing:

• Assess SpO₂ (hypoxia common during seizure)
• Apply high-flow oxygen (15L via non-rebreathe mask)
• Look for cyanosis
• Listen for aspiration (gurgling, stridor)
• Prepare for intubation if persistent hypoxia or prolonged SE

Circulation:

• Heart rate (tachycardia expected initially)
• Blood pressure (hypertension early, hypotension late)
• Obtain IV access (large bore cannula × 2)
• Cardiac monitoring

Disability:

• Glasgow Coma Scale (typically 3-8 during active seizure)
• Pupil size and reactivity (may be dilated during seizure)
• Blood glucose (bedside capillary)
• Temperature (rectal or core temperature if available)
• Observe seizure semiology and time duration

Exposure:

• Look for signs of trauma (head injury, shoulder dislocation, fractures)
• Rash (meningococcal, viral exanthem)
• Evidence of chronic liver disease (alcohol-related SE)
• Medic-alert bracelet (known epilepsy)
• Tongue or cheek biting (lateral tongue bite specific for epileptic seizure)

During Seizure

Observe and document:

• Time of onset: Critical for defining SE (> 5 minutes)
• Seizure semiology:
  • Focal or generalised onset?
  • Eye deviation (suggests focal onset from contralateral hemisphere)
  • Unilateral or bilateral movements?
  • Tonic, clonic, or tonic-clonic phases
• Colour: Cyanosis indicates hypoxia
• Automatisms: Lip smacking, chewing, hand automatisms

Safety:

• Move objects away to prevent injury
• Cushion head
• Loosen tight clothing
• Never restrain (risk of fractures, rhabdomyolysis)

Post-Ictal Examination

Neurological examination:

• GCS: Recovery expected over 5-30 minutes; persistent coma suggests NCSE, structural lesion, or prolonged SE
• Focal neurological signs:
  • "Todd's paresis: Temporary focal weakness after focal seizure (resolves within 24-48 hours); suggests focal onset"
  • Aphasia (suggests left hemisphere involvement)
  • Visual field defects
• Pupil examination: Size, reactivity (may remain dilated post-ictally)
• Plantars: Bilateral upgoing plantars common post-ictally; asymmetry suggests focal pathology

Systemic examination:

• Temperature: Fever suggests infection or hyperthermia from prolonged SE
• Cardiovascular: Arrhythmias, hypotension (late sign)
• Respiratory: Signs of aspiration pneumonia
• Musculoskeletal: Palpate shoulders (posterior dislocation), spine (compression fractures), long bones

Signs of specific aetiologies:

• Meningism: Neck stiffness, photophobia (meningitis, SAH)
• Papilloedema: Raised ICP (tumour, abscess, encephalitis)
• Rash: Petechial (meningococcal), vesicular (HSV encephalitis)
• Alcohol: Smell of alcohol, stigmata of chronic liver disease, tremor

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Investigations

Immediate Bedside Tests (Within 5 Minutes)

Laboratory Investigations

Blood tests (all patients):

Additional tests (selected patients):

Neuroimaging

Indications for urgent CT head (within 1 hour):

• New-onset SE (no history of epilepsy)
• Focal neurological signs
• Focal seizure onset
• Head trauma
• Persistent altered consciousness after seizure cessation
• Suspected structural lesion (tumour, abscess, haemorrhage)
• Age > 60 years with first seizure

MRI brain:

• More sensitive than CT for:
  • Acute stroke (DWI sequence)
  • Encephalitis (HSV, autoimmune)
  • Posterior reversible encephalopathy syndrome (PRES)
  • Cortical dysplasia
• Perform when patient stabilised (often requires general anaesthesia)

CT/MR angiography:

• Suspected cerebral venous sinus thrombosis
• Vasculitis

Lumbar Puncture

Indications:

• Suspected CNS infection (meningitis, encephalitis)
• Fever with no obvious source
• Subacute onset with encephalopathy (autoimmune encephalitis)

Contraindications:

• Raised intracranial pressure (papilloedema, midline shift on imaging)
• Coagulopathy (correct first)
• Haemodynamic instability (defer until stabilised)

CSF analysis:

• Cell count and differential
• Protein, glucose (paired with blood glucose)
• Gram stain and culture
• HSV, VZV PCR
• Oligoclonal bands (if autoimmune suspected)
• Autoimmune encephalitis antibodies (NMDA, LGI1, CASPR2, GAD)

Electroencephalography (EEG)

Indications for urgent EEG:

• Suspected non-convulsive status epilepticus (altered consciousness without convulsions)
• Persistent coma after convulsive SE cessation
• Subtle motor manifestations (eye deviation, twitching) with altered consciousness
• Post-cardiac arrest (prognostication)

Continuous EEG monitoring:

• All patients in ICU with refractory SE
• Monitor for seizure recurrence
• Assess depth of burst suppression during anaesthetic coma
• Guide weaning of anaesthetic agents

EEG findings:

• Generalised convulsive SE: Continuous or near-continuous generalised spike-wave or polyspike-wave
• Focal SE: Continuous focal epileptiform activity
• Subtle SE: Periodic discharges, evolving rhythmic activity despite minimal motor signs
• Burst suppression: Target pattern during anaesthetic coma for refractory SE

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Classification and Staging

Classification by Duration (Operational)

Status epilepticus is staged based on duration and response to treatment:

Classification by Semiology

Based on the 2015 ILAE classification:

1. With prominent motor symptoms:

• Convulsive SE (tonic-clonic, tonic, clonic)
• Myoclonic SE (generalised or focal)
• Focal motor SE
• Tonic SE
• Hyperkinetic SE

2. Without prominent motor symptoms (non-convulsive SE):

• Non-convulsive SE with coma
• Non-convulsive SE without coma (absence SE, complex partial SE)

Classification by Aetiology

Symptomatic:

• Acute symptomatic: Acute brain insult (stroke, trauma, infection, metabolic) within 7 days
• Remote symptomatic: Pre-existing brain lesion (old stroke, TBI, cortical dysplasia)

Idiopathic generalised epilepsy:

• Absence status
• Generalised tonic-clonic SE in genetic generalised epilepsy

Cryptogenic:

• No identifiable cause despite thorough investigation

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Management

Overview of Treatment Approach

Management of status epilepticus follows a time-based protocol with three treatment stages:

1. First-line (0-10 minutes): Benzodiazepines
2. Second-line (10-30 minutes): Anti-seizure medications (levetiracetam, phenytoin, valproate)
3. Third-line (> 30 minutes): General anaesthesia in ICU

Treatment must be initiated simultaneously with:

• Supportive care (airway, oxygen, IV access)
• Investigation to identify underlying cause
• Treatment of reversible causes

Time-Based Treatment Protocol

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STAGE 0-5 MINUTES: STABILISATION AND ASSESSMENT

Immediate actions:

1. Call for help: Activate emergency response

2. Time the seizure: Start timing from onset or first observation

3. ABCDE assessment:

   • Airway: Recovery position, clear secretions
   • Breathing: Oxygen 15L via non-rebreathe mask
   • Circulation: Obtain IV access (×2 large bore cannulae)
   • Disability: Check glucose, observe seizure
   • Exposure: Look for injury, rash, evidence of cause

4. Bedside tests:

   • Capillary blood glucose → if less than 3 mmol/L: give 50ml 50% dextrose IV
   • SpO₂, temperature, ECG

5. Blood tests: Send FBC, U&E, LFTs, bone profile, glucose, CK, VBG/ABG, AED levels if known epilepsy

6. Treat hypoglycaemia if present:

   • 50ml 50% dextrose IV (or 100ml 10% dextrose)
   • Thiamine 250mg IV if malnourished/alcohol-related (give before or with glucose to prevent Wernicke's encephalopathy)

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STAGE 1 (5-10 MINUTES): FIRST-LINE BENZODIAZEPINES

IF seizure continues for ≥5 minutes, give benzodiazepine immediately:

First-line options: [8]

Lorazepam vs midazolam:

• Lorazepam: Longer half-life (12-14 hours), less respiratory depression, preferred if IV access available
• Midazolam: Faster onset, IM/buccal route bypasses need for IV access; RAMPART trial showed IM midazolam non-inferior to IV lorazepam [8]

Repeat dosing:

• If seizure continues after 5-10 minutes, give second dose of same benzodiazepine
• Maximum 2 doses of benzodiazepines before escalating to second-line
• Further benzodiazepines increase risk of respiratory depression without additional efficacy

Response:

• ~60-70% of patients will have seizure cessation with first-line benzodiazepines [8]
• If no response after 2 doses, proceed immediately to second-line therapy

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STAGE 2 (10-30 MINUTES): SECOND-LINE ANTI-SEIZURE MEDICATIONS

If seizure continues despite 2 doses of benzodiazepines, give second-line AED immediately:

Choose ONE of the following: [6]

ESETT Trial findings: [6]

• Levetiracetam, fosphenytoin, and valproate have similar efficacy (~45-50% seizure cessation) when used as second-line therapy
• No significant difference in safety outcomes
• Choice should be individualised based on:
  • "Pregnancy: Use levetiracetam (avoid valproate)"
  • "Liver disease: Use levetiracetam (avoid valproate)"
  • "Hypotension: Use levetiracetam or valproate (avoid phenytoin)"
  • "Alcohol withdrawal SE: Phenytoin or valproate may be preferred"
  • "Renal impairment: Adjust levetiracetam dose"

Monitoring:

• Continuous cardiac monitoring if using phenytoin
• Blood pressure monitoring (all agents can cause hypotension)

Response:

• Assess at 20 minutes after second-line AED given
• If seizure continues, patient has refractory status epilepticus → escalate to third-line

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STAGE 3 (> 30 MINUTES): REFRACTORY STATUS EPILEPTICUS - ICU MANAGEMENT

If seizure continues > 30 minutes or persists despite first-line and second-line therapy → REFRACTORY SE

Immediate actions:

1. Call ICU/anaesthetics for intubation and transfer to ICU
2. Rapid sequence induction and intubation
3. General anaesthesia with intravenous anaesthetic infusion
4. Continuous EEG monitoring (24-48 hours minimum)

Third-line anaesthetic agents: [7]

EEG targets: [7]

• Burst suppression: Alternating periods of electrical silence and bursts of activity
  • "Interburst interval: 2-20 seconds"
• Alternative target: Complete seizure suppression without burst suppression
• Continuous EEG monitoring essential to guide dosing

Duration of anaesthesia:

• Maintain for 24-48 hours after last clinical or electrographic seizure
• Attempt gradual weaning while monitoring EEG
• If seizures recur during weaning → return to burst suppression for further 24 hours

Supportive care in ICU:

• Vasopressor support: Noradrenaline for hypotension (common with propofol, thiopentone)
• Mechanical ventilation: Intubated patients
• Temperature management: Active cooling if hyperthermia (> 38.5°C)
• Fluid resuscitation: For rhabdomyolysis, hypotension
• DVT prophylaxis: Pharmacological and mechanical
• Nutrition: Enteral feeding via NG tube

Additional AEDs:

• Continue or add maintenance AEDs alongside anaesthesia:
  • Levetiracetam, phenytoin, valproate, lacosamide, topiramate
• Aim for polytherapy to facilitate anaesthetic weaning

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STAGE 4: SUPER-REFRACTORY STATUS EPILEPTICUS

Definition: SE continuing for ≥24 hours despite anaesthetic treatment OR recurrent SE on weaning of anaesthesia

Incidence: 10-15% of SE cases [14]

Treatment options (limited evidence):

Immunotherapy: [15]

• Consider if autoimmune aetiology suspected (autoimmune encephalitis)
• IV methylprednisolone: 1g daily for 3-5 days
• IV immunoglobulin (IVIg): 0.4 g/kg/day for 5 days
• Plasma exchange (PLEX): If antibody-mediated (NMDA receptor, LGI1, CASPR2)
• Rituximab: For refractory autoimmune SE

Ketogenic diet:

• Enteral ketogenic diet (4:1 fat:carbohydrate+protein ratio)
• May reduce seizure frequency in super-refractory SE
• Requires specialist dietitian support

Experimental therapies:

• Hypothermia: 31-35°C for 24-48 hours
• Electroconvulsive therapy (ECT): Case reports of success
• Ketamine: NMDA antagonist; case series suggest benefit
• Magnesium sulphate infusion: NMDA antagonist
• Neurosurgical resection: If focal lesion identified

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Treatment of Underlying Cause

Concurrent with anti-seizure treatment, identify and treat underlying aetiology:

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Special Populations

Pregnancy:

• First-line: Benzodiazepines (safe in pregnancy)
• Second-line: Levetiracetam preferred (avoid valproate - teratogenic)
• Eclampsia: Magnesium sulphate is first-line (4g IV load, then 1g/hr)

Elderly:

• Lower doses of benzodiazepines (risk of respiratory depression)
• Avoid phenytoin if cardiac comorbidities
• Higher mortality and morbidity

Renal impairment:

• Reduce levetiracetam dose (renally excreted)
• Adjust other AEDs according to renal function

Liver impairment:

• Avoid valproate
• Caution with benzodiazepines and other hepatically metabolised drugs

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Non-Convulsive Status Epilepticus (NCSE)

Management principles: [9]

• Less urgency than convulsive SE (neuronal injury slower)
• Treatment guided by clinical context:
  • "Comatose patients: Treat as convulsive SE (benzodiazepines, second-line AEDs)"
  • "Non-comatose patients: Start with non-sedating AED (levetiracetam, valproate)"
• EEG monitoring essential to assess treatment response

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Complications

Neurological Complications

Acute:

• Hypoxic-ischaemic brain injury: Cerebral oedema, herniation
• Raised intracranial pressure: Requires monitoring and treatment
• Stroke: Haemorrhagic or ischaemic (rare)

Subacute/Chronic:

• Hippocampal sclerosis: Mesial temporal sclerosis leading to temporal lobe epilepsy
• Cognitive impairment: Memory deficits, executive dysfunction (20-30% of survivors)
• New-onset epilepsy: 15-25% develop epilepsy after SE
• Persistent vegetative state: Anoxic SE

Systemic Complications

Respiratory:

• Aspiration pneumonia: Common (20-30% of cases)
• Pulmonary oedema: Neurogenic or cardiogenic
• Acute respiratory distress syndrome (ARDS): Prolonged ventilation

Cardiovascular:

• Arrhythmias: Atrial fibrillation, VT/VF (rare)
• Myocardial infarction: Demand ischaemia
• Hypotension: Multi-factorial (anaesthetics, systemic inflammatory response)
• Cardiac arrest: Severe cases

Renal:

• Acute kidney injury: Rhabdomyolysis (myoglobin nephrotoxicity), hypotension, ATN
• Electrolyte disturbances: Hyperkalaemia (rhabdomyolysis), hyponatraemia (SIADH)

Metabolic:

• Rhabdomyolysis: Elevated CK (> 1000 U/L), myoglobinaemia, dark urine
• Hyperthermia: Core temperature > 40°C (associated with poor prognosis)
• Lactic acidosis: Metabolic acidosis from anaerobic metabolism
• Hypoglycaemia: Late complication after initial hyperglycaemia

Haematological:

• Disseminated intravascular coagulation (DIC): Prolonged SE, hyperthermia
• Thrombocytopenia: DIC, sepsis

Musculoskeletal:

• Fractures: Vertebral compression fractures (T12, L1), long bone fractures
• Dislocations: Posterior shoulder dislocation (bilateral in 3% of SE)
• Soft tissue injuries: Tongue/cheek biting, lacerations

Infectious:

• Hospital-acquired pneumonia: Aspiration, prolonged ventilation
• Catheter-related infections: Central lines, urinary catheters
• Sepsis: Multi-factorial

Treatment-Related Complications

Benzodiazepines:

• Respiratory depression (requiring intubation in 10-20%)
• Hypotension (less common than with other agents)

Phenytoin:

• Hypotension and arrhythmias (especially if infused too rapidly)
• Purple glove syndrome (extravasation causing limb ischaemia - requires vascular surgery)
• Cardiac arrest (rare, rapid infusion in elderly/cardiac disease)

Propofol:

• Propofol infusion syndrome (PRIS): Rare but potentially fatal
  • Metabolic acidosis, rhabdomyolysis, hyperkalaemia, cardiac failure
  • Risk increases with doses > 5 mg/kg/hr for > 48 hours
  • "Monitor: Lactate, CK, triglycerides, ECG"
  • "Treatment: Stop propofol, supportive care"

General anaesthesia:

• Prolonged ventilation and ICU stay
• Ventilator-associated pneumonia
• ICU-acquired weakness
• Delirium

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Prognosis and Outcomes

Mortality

Overall mortality: 10-20% [4,11]

Mortality by SE type:

• Generalised convulsive SE: 15-20%
• Refractory SE: 30-40%
• Super-refractory SE: 40-50%
• Non-convulsive SE: 10-30% (depends on underlying cause)

Mortality by aetiology: [11]

• Anoxic SE (post-cardiac arrest): 60-80%
• CNS infection (meningitis, encephalitis): 20-40%
• Acute symptomatic (stroke, metabolic): 20-30%
• Remote symptomatic (known epilepsy): 5-10%
• Alcohol-related SE: 5-15%

Prognostic Factors

Associated with higher mortality:

• Advanced age (> 65 years)
• Longer duration of SE (> 60 minutes)
• Refractory or super-refractory SE
• Anoxic or infectious aetiology
• Multiple comorbidities (cardiac, renal, hepatic disease)
• Need for mechanical ventilation
• Hyperthermia (> 40°C)
• Elevated lactate (> 5 mmol/L)

Associated with better prognosis:

• Young age
• Early seizure termination (less than 30 minutes)
• Remote symptomatic or idiopathic aetiology
• Prompt treatment
• Absence of significant comorbidities

Long-Term Outcomes

Functional outcomes (survivors):

• Good recovery (return to baseline): 50-70%
• New neurological deficit: 10-20%
• Severe disability or vegetative state: 5-10%

Neurological sequelae:

• Cognitive impairment: 20-30% (memory, executive function, processing speed)
• New-onset epilepsy: 15-25%
• Recurrent status epilepticus: 10-15%
• Psychiatric disorders: Depression, anxiety, PTSD

Quality of life:

• Many survivors report reduced quality of life
• Employment difficulties
• Driving restrictions (seizure-free period required)

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Evidence and Guidelines

Key International Guidelines

1. Neurocritical Care Society Guidelines (2012) - Brophy GM, et al. [1]

   • Comprehensive evidence-based guidelines for evaluation and management
   • Three-tier treatment approach

2. American Epilepsy Society Guidelines (2016, updated 2020) - Vossler DG, et al. [7]

   • Evidence-based review of treatment for refractory convulsive SE
   • Recommendations on third-line anaesthetic agents

3. NICE Guidelines CG137 (updated 2022) - Epilepsies: Diagnosis and Management

   • UK-specific guidance on SE management in adults and children

4. European Federation of Neurological Societies (EFNS) Guidelines (2010)

   • European consensus on SE management

5. Italian Clinical Practice Guidelines (2024) - Vignatelli L, et al. [16]

   • Systematic review of adult SE management guidelines

Landmark Trials and Studies

First-line benzodiazepines:

RAMPART Trial (2012) - Silbergleit R, et al. [8]

• Randomised trial: IM midazolam vs IV lorazepam for pre-hospital SE
• Result: IM midazolam non-inferior to IV lorazepam (seizure cessation: 73% vs 63%, pless than 0.05)
• Impact: Established IM/buccal midazolam as acceptable first-line when IV access unavailable

Second-line anti-seizure medications:

ESETT Trial (2019) - Kapur J, et al. [6]

• Randomised trial: Levetiracetam vs fosphenytoin vs valproate as second-line for benzodiazepine-refractory SE
• Result: No significant difference in seizure cessation (levetiracetam 47%, fosphenytoin 45%, valproate 46%)
• Impact: Established that all three agents are equally effective; choice should be individualised

ConSEPT Trial (2019) - Lyttle MD, et al.

• Levetiracetam vs phenytoin in paediatric convulsive SE
• Similar efficacy and safety profiles

Third-line anaesthetics:

Evidence is largely observational (no RCTs comparing anaesthetic agents):

• Retrospective studies suggest similar efficacy of propofol, midazolam, and thiopentone
• Choice guided by side effect profile and institutional preference

Non-convulsive status epilepticus:

Observational studies suggest:

• NCSE accounts for 20-40% of SE cases [9]
• Delayed diagnosis common
• Prognosis depends on underlying aetiology more than seizure duration

Key Evidence Summary

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Patient and Family Information

What is Status Epilepticus?

Status epilepticus is a medical emergency where a seizure lasts longer than 5 minutes, or when seizures happen one after another without the person waking up in between. It is not a normal seizure - the brain's usual "stop" mechanisms fail, and the seizure continues.

Why is it Dangerous?

When a seizure continues for a long time:

• The brain uses more energy than it receives, causing brain cell damage
• Breathing can be affected, reducing oxygen to the brain
• Body temperature can rise dangerously high
• Muscles break down (rhabdomyolysis), which can damage the kidneys
• Without treatment, status epilepticus can cause permanent brain damage or death

What Causes Status Epilepticus?

Common causes include:

• Not taking epilepsy medication (most common in people with known epilepsy)
• Alcohol withdrawal or excessive alcohol use
• Stroke or brain bleeding
• Infections of the brain (meningitis, encephalitis)
• Very low blood sugar (hypoglycaemia)
• Head injury
• Drug overdose or toxicity

What to Do If Someone Has a Prolonged Seizure

Call 999 immediately if:

• A seizure lasts more than 5 minutes
• Seizures happen repeatedly without the person waking up
• The person is injured or having difficulty breathing

While waiting for help:

1. Stay calm and stay with the person
2. Time the seizure (important for doctors)
3. Move objects away to prevent injury
4. Cushion their head with something soft
5. Turn them on their side (recovery position) to help breathing
6. DO NOT put anything in their mouth (risk of choking or injury)
7. DO NOT restrain them or try to stop the movements
8. If they have been prescribed emergency medication (buccal midazolam or rectal diazepam), give it

Treatment in Hospital

Immediate treatment:

• Medication to stop the seizure (usually given into a vein or into the cheek)
• Oxygen to help breathing
• Blood tests to find the cause
• Sometimes a brain scan

If seizures don't stop:

• Stronger medications
• Admission to intensive care
• Breathing machine (ventilator)
• Continuous brain monitoring (EEG)

After Status Epilepticus

In hospital:

• Investigation to find the cause (blood tests, brain scans, sometimes lumbar puncture)
• Treatment of any underlying problem (infection, low blood sugar, etc.)
• Review of epilepsy medications if you have epilepsy
• Monitoring for complications

Recovery:

• Most people recover fully if treated quickly
• Some people feel confused or tired for several days
• Some people may have memory problems or new difficulties

Follow-up:

• Neurology clinic appointment
• Review of medications
• Discuss preventing future episodes

Preventing Future Episodes

If you have epilepsy:

• Take medications regularly (most important)
• Get enough sleep
• Avoid excessive alcohol
• Manage stress
• Attend regular neurology appointments
• Inform your doctor of any missed medications or new symptoms

Emergency medication at home:

• Some people at high risk are prescribed "rescue medication" (buccal midazolam or rectal diazepam)
• Family members or carers should be trained to give this if a seizure lasts > 5 minutes

Driving and Work

After status epilepticus:

• You must not drive (UK law requires 12 months seizure-free for car/motorcycle licence)
• Inform the DVLA
• Discuss return to work with your doctor
• Some activities (operating machinery, working at heights) may require restrictions

Support and Resources

UK organisations:

• Epilepsy Action: 0808 800 5050 | epilepsy.org.uk
• Epilepsy Society: 01494 601 400 | epilepsysociety.org.uk
• NHS Epilepsy Information: nhs.uk/conditions/epilepsy

International:

• Epilepsy Foundation (US): epilepsy.com
• International League Against Epilepsy: ilae.org

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References

Guidelines and Consensus Statements

1. Brophy GM, Bell R, Claassen J, et al. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012;17(1):3-23. doi:10.1007/s12028-012-9695-z [PMID: 22528274]

2. Trinka E, Cock H, Hesdorffer D, et al. A definition and classification of status epilepticus - Report of the ILAE Task Force on Classification of Status Epilepticus. Epilepsia. 2015;56(10):1515-1523. doi:10.1111/epi.13121 [PMID: 26336950]

3. Rossetti AO, Lowenstein DH. Management of refractory status epilepticus in adults: still more questions than answers. Lancet Neurol. 2011;10(10):922-930. doi:10.1016/S1474-4422(11)70187-9 [PMID: 21939901]

4. Logroscino G, Hesdorffer DC, Cascino GD, et al. Long-term mortality after a first episode of status epilepticus. Neurology. 2002;58(4):537-541. doi:10.1212/wnl.58.4.537 [PMID: 11865130]

5. Alldredge BK, Gelb AM, Isaacs SM, et al. A comparison of lorazepam, diazepam, and placebo for the treatment of out-of-hospital status epilepticus. N Engl J Med. 2001;345(9):631-637. doi:10.1056/NEJMoa002141 [PMID: 11547716]

6. Kapur J, Elm J, Chamberlain JM, et al. Randomized Trial of Three Anticonvulsant Medications for Status Epilepticus. N Engl J Med. 2019;381(22):2103-2113. doi:10.1056/NEJMoa1905795 [PMID: 31774955]

7. Vossler DG, Bainbridge JL, Boggs JG, et al. Treatment of Refractory Convulsive Status Epilepticus: A Comprehensive Review by the American Epilepsy Society Treatments Committee. Epilepsy Curr. 2020;20(5):245-264. doi:10.1177/1535759720928269 [PMID: 32822230]

8. Silbergleit R, Durkalski V, Lowenstein D, et al. Intramuscular versus intravenous therapy for prehospital status epilepticus. N Engl J Med. 2012;366(7):591-600. doi:10.1056/NEJMoa1107494 [PMID: 22335736]

Pathophysiology and Mechanisms

9. Sutter R, Kaplan PW. Clinical and electroencephalographic correlates of acute encephalopathy. J Clin Neurophysiol. 2013;30(5):443-453. doi:10.1097/WNP.0b013e3182a73bc2 [PMID: 24084176]

10. DeLorenzo RJ, Hauser WA, Towne AR, et al. A prospective, population-based epidemiologic study of status epilepticus in Richmond, Virginia. Neurology. 1996;46(4):1029-1035. doi:10.1212/wnl.46.4.1029 [PMID: 8780085]

11. Raspall-Chaure M, Chin RF, Neville BG, Scott RC. Outcome of paediatric convulsive status epilepticus: a systematic review. Lancet Neurol. 2006;5(9):769-779. doi:10.1016/S1474-4422(06)70546-4 [PMID: 16914405]

12. Naylor DE, Liu H, Wasterlain CG. Trafficking of GABA(A) receptors, loss of inhibition, and a mechanism for pharmacoresistance in status epilepticus. J Neurosci. 2005;25(34):7724-7733. doi:10.1523/JNEUROSCI.4944-04.2005 [PMID: 16120773]

13. Chen JW, Wasterlain CG. Status epilepticus: pathophysiology and management in adults. Lancet Neurol. 2006;5(3):246-256. doi:10.1016/S1474-4422(06)70374-X [PMID: 16488380]

Refractory and Super-Refractory Status Epilepticus

14. Shorvon S, Ferlisi M. The treatment of super-refractory status epilepticus: a critical review of available therapies and a clinical treatment protocol. Brain. 2011;134(Pt 10):2802-2818. doi:10.1093/brain/awr215 [PMID: 21914716]

15. Gaspard N, Foreman BP, Alvarez V, et al. New-onset refractory status epilepticus: Etiology, clinical features, and outcome. Neurology. 2015;85(18):1604-1613. doi:10.1212/WNL.0000000000001940 [PMID: 26296517]

16. Vignatelli L, Tontini V, Meletti S, et al. Clinical practice guidelines on the management of status epilepticus in adults: A systematic review. Epilepsia. 2024;65(6):1512-1530. doi:10.1111/epi.17982 [PMID: 38606469]

Intensive Care and EEG Monitoring

17. Rossetti AO, Claassen J, Gaspard N. Status epilepticus in the ICU. Intensive Care Med. 2024;50(1):1-16. doi:10.1007/s00134-023-07263-w [PMID: 38117319]

18. Betjemann JP, Lowenstein DH. Status epilepticus in adults. Lancet Neurol. 2015;14(6):615-624. doi:10.1016/S1474-4422(15)00042-3 [PMID: 25908090]

Specific Populations and Subtypes

19. Claassen J, Taccone FS, Horn P, et al. Recommendations on the use of EEG monitoring in critically ill patients: consensus statement from the neurointensive care section of the ESICM. Intensive Care Med. 2013;39(8):1337-1351. doi:10.1007/s00134-013-2938-4 [PMID: 23708645]

20. Zelano J, Kumlien E. Levetiracetam as alternative stage two antiepileptic drug in status epilepticus: a systematic review. Seizure. 2012;21(4):233-236. doi:10.1016/j.seizure.2012.01.004 [PMID: 22285370]

Outcomes and Prognosis

21. Sutter R, Marsch S, Fuhr P, et al. Anesthetic drugs in status epilepticus: risk or rescue? A 6-year cohort study. Neurology. 2014;82(8):656-664. doi:10.1212/WNL.0000000000000009 [PMID: 24319039]

22. Giovannini G, Monti G, Polisi MM, et al. A one-year prospective study of refractory status epilepticus in Modena, Italy. Epilepsia. 2015;56(1):e5-e8. doi:10.1111/epi.12863 [PMID: 25410912]

23. Meierkord H, Boon P, Engelsen B, et al. EFNS guideline on the management of status epilepticus in adults. Eur J Neurol. 2010;17(3):348-355. doi:10.1111/j.1468-1331.2009.02917.x [PMID: 20050893]

24. Rosenow F, Hamer HM, Knake S. The epidemiology of convulsive and nonconvulsive status epilepticus. Epilepsia. 2007;48 Suppl 8:82-84. doi:10.1111/j.1528-1167.2007.01362.x [PMID: 18330000]

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Acknowledgements

This topic was developed following evidence-based medicine principles with systematic PubMed literature review. All clinical recommendations are supported by published evidence from peer-reviewed journals and international consensus guidelines.

Last Updated: January 8, 2026
Next Review: January 2027
Evidence Level: High (based on RCTs and international guidelines)

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For clinical decision support, always refer to local protocols and guidelines. This resource is for educational purposes and does not replace clinical judgement.