What is status epilepticus?

Status Epilepticus: Definition and Management

Status epilepticus is a life-threatening neurological emergency defined as a seizure lasting longer than 5 minutes or multiple seizures without return to neurological baseline between episodes, requiring immediate intervention to prevent significant morbidity and mortality. 1, 2

Definition and Epidemiology

Status epilepticus (SE) is characterized by:

• Prolonged seizure activity (traditionally defined as ≥30 minutes, but now recognized as ≥5 minutes) 1
• Recurrent seizures without recovery of consciousness between episodes 1
• Occurs in approximately 50,000-150,000 patients annually in the United States 1
• Mortality rates range from 5-22%, increasing to as high as 65% in cases refractory to first-line therapies 1
• Incidence of approximately 36.1 per 100,000 person-years 3

According to the World Health Organization, status epilepticus is "a condition characterized by an epileptic seizure that is sufficiently prolonged or repeated at sufficiently brief intervals so as to produce an unvarying and enduring epileptic condition." 1

Pathophysiology and Etiology

Status epilepticus results from either:

• Failure of seizure termination mechanisms
• Abnormal seizure initiation processes 4

Common causes include:

• Cerebrovascular disorders (stroke, hemorrhage)
• Brain trauma
• Central nervous system infections
• Low antiepileptic drug levels in patients with epilepsy
• Metabolic derangements (hypoglycemia, hyponatremia)
• Alcohol withdrawal
• Inflammatory causes
• Toxins and drug effects 5

Clinical Presentation

Status epilepticus may present as:

• Generalized convulsive status epilepticus (most recognizable form)
• Focal status epilepticus
• Nonconvulsive status epilepticus (may present as altered mental status without obvious seizure activity)

Management Algorithm

Immediate Actions (0-5 minutes)

1. Ensure airway patency and adequate oxygenation
2. Establish IV access
3. Monitor vital signs
4. Position patient to prevent aspiration
5. Obtain rapid glucose measurement

First-Line Treatment (5-20 minutes)

• Benzodiazepines are the established first-line therapy:
  • Lorazepam 4 mg IV given slowly (2 mg/min) for adults 6
  • If seizures continue after 10-15 minutes, an additional 4 mg IV dose may be administered 6

Second-Line Treatment (20-40 minutes)

If seizures persist despite optimal benzodiazepine dosing:

• Administer one of the following (Level B recommendation) 1:
  • Fosphenytoin/Phenytoin (20 mg/kg IV)
  • Valproate (20-30 mg/kg IV)
  • Levetiracetam (60 mg/kg, up to 4500 mg IV)

Valproate may be preferred due to fewer cardiovascular side effects compared to phenytoin 1, 2

Third-Line Treatment (40-60 minutes)

For refractory status epilepticus:

• Consider anesthetic agents (Level C recommendation) 1:
  • Propofol
  • Midazolam
  • Barbiturates

Concurrent Management

• Search for and treat underlying causes:
  • Hypoglycemia
  • Electrolyte abnormalities
  • Infection
  • Toxins
  • Stroke or hemorrhage 1
• Continuous EEG monitoring when available, especially for patients with altered mental status 2
• Monitor for and manage complications (respiratory depression, hypotension, cardiac arrhythmias)

Prognosis and Complications

The three major determinants of prognosis are:

1. Duration of status epilepticus (longer duration = worse outcomes) 7
2. Patient age (extremes of age have worse outcomes)
3. Underlying cause 5

Potential complications include:

• Neuronal damage and brain injury
• Aspiration pneumonia
• Cardiac arrhythmias
• Respiratory failure
• Metabolic acidosis
• Hyperthermia
• Rhabdomyolysis

Key Clinical Considerations

• Time is brain: Delays in treatment significantly worsen outcomes. Patients receiving antiepileptic drugs within 1 hour have better outcomes 7
• Equipment for airway management must be immediately available before administering IV benzodiazepines 6
• Continuous EEG monitoring is crucial for diagnosis of nonconvulsive status epilepticus and to confirm seizure cessation 4
• Institutional protocols improve care and reduce treatment delays 4
• Treatment must address three pillars: stop seizures, stabilize the patient, and treat underlying causes 4

Status epilepticus requires prompt recognition and aggressive treatment to prevent significant morbidity and mortality. The evolution of treatment protocols and definitions has helped improve outcomes, but it remains a neurological emergency with substantial risks.