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Definition

• A state of continuous seizures or repetitive, discrete seizures with impaired consciousness in the interictal period
  • Duration
    • Traditional criterion: 15–30 minutes
    • Practical criterion: duration prompting acute use of anticonvulsant therapy; typically > 5 minutes
  • May occur with all type of seizures: grand mal (tonic-clonic) status, myoclonic status, petit mal status, and temporal lobe (complex partial) status
  • Associated with major cerebral and systemic physiologic changes
    • Initial stage (first 30–60 minutes)
      • Cerebral metabolism is greatly increased because of seizure activity, but physiologic mechanisms are sufficient to meet the metabolic demands.
      • Cerebral: increased blood flow, increased metabolism
      • Autonomic and cardiovascular: hypertension, increased cardiac output, massive catecholamine release, tachycardia, arrhythmias, hyperpyrexia
      • Metabolic: lactic acidosis, hyperglycemia
    • Decompensated phase
      • Cerebral metabolic demands cannot be fully met, resulting in hypoxia and altered cerebral and systemic metabolic patterns.
      • Cerebral: hypoxia, hypoglycemia, increased intracranial pressure
      • Autonomic and cardiovascular: hypoxia, hypotension, hyperpyrexia
      • Metabolic: hypoglycemia, hyponatremia, hyperkalemia, metabolic acidosis
  • Generalized status is life threatening when accompanied by hyperpyrexia, acidosis (from prolonged muscle activity), and respiratory or cardiovascular compromise.

Epidemiology

• Incidence in the U.S.
  • 18–50 cases per 100,000 annually
    • Half are secondary to acute central nervous system (CNS) insult.
    • One-third are unprovoked first seizure.
    • One-sixth are in patients with known epilepsy.
      • Noncompliance with medications is primary risk factor in patients with known epilepsy.
• Prevalence
  • Occurs in ~10% of children who have diagnosis of epilepsy
• Age
  • More common in children, especially in first year of life
  • More common in patients older than age 60
• Sex
  • Occurs equally in males and females
    

Risk Factors

• Anticonvulsant withdrawal or noncompliance
• Previous incident of status epilepticus (SE)
• Refractory epilepsy
• Head trauma
• Metabolic disturbances
• Drug toxicity
• CNS infection
• CNS tumors
• Cerebrovascular disease
• Fever (especially in children)

Etiology

• Seizures are caused by a shift in the normal balance of excitation and inhibition within the CNS.
• SE occurs in 3 general clinical scenarios.
  • SE precipitated by focal or global CNS injury
    • Head trauma
    • Metabolic disturbance (e.g., hyponatremia, hypoglycemia)
    • Infection (encephalitis, abscess)
    • Drugs (both prescription and illicit)
    • Brain tumor
    • Stroke (acute or remote), hypoxia
  • SE as initial presentation of a seizure disorder
  • SE as exacerbation of known epilepsy
    • Primary risk factor is noncompliance with medications.
    • More common in patients with prior history of SE

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