Status Epilepticus

Introduction

Most seizures are brief and end within 1 to 3 minutes without drug treatment.

Status epilepticus refers to continuous seizure activity or repeated seizures without full recovery of consciousness between attacks.

  • The minimum duration of continuous seizure activity required for the diagnosis of status epilepticus is traditionally agreed to be 30 minutes.
  • However, drug treatment for a seizure should start after 5 minutes of continuous seizure activity.

Status epilepticus may be convulsive (e.g. tonic-clonic) or nonconvulsive (e.g. absence status epilepticus).

  • The treatment of nonconvulsive status epilepticus is less urgent and the risks of therapy, particularly respiratory depression, must be weighed against the risks of continuing nonconvulsive seizures.

NOTE: Patients with a single episode of status epilepticus have a 10-30% risk of a lifetime recurrence and a 20-40% chance of developing epilepsy.



Some Causes of Acute Symptomatic Seizures

Resolution of the cause usually stops the seizure. Seizures will recur if the causes recur (e.g. during benzodiazepine withdrawal) or if the acute illness has caused permanent brain injury.

  • Provided the cause of an acute symptomatic seizure has been corrected, continued antiepileptic drug therapy is not needed. Nonetheless, there are cases when the cause is not immediately reversible (e.g. bacterial meningitis, eclampsia).

Some causes of acute symptomatic seizures

  • Metabolic disorders
    • Hypoglycemia
    • Hyponatremia
    • Hypocalcemia
    • Kidney failure
  • Intoxication with some drugs or poisons
  • Drug or alcohol withdrawal
  • Stroke (ischaemic or haemorrhagic)
  • Brain trauma (including neurosurgery)
  • Intracranial infection
    • Meningitis (non-viral)
    • Encephalitis
    • Cerebral abscess
  • Autoimmune encephalitis
  • Hypertensive encephalopathy
  • Severe cerebral hypoxia (e.g. cardiac arrest)
  • Eclampsia



Acute Management

Step 1: Give a benzodiazepine.

  • Start drug treatment (e.g. midazolam, diazepam or clonazepam)
    • After 5 minutes of continuous seizure activity
    • When the patient has repeated seizures without full recovery of consciousness between attacks.
  • An immediate electroencephalogram (EEG) should obtained if possible.
  • Most patients need to be intubated.

Step 2: Give an antiepileptic drug

  • Unless if the cause of seizure can be reversed immediately, starting treatment with an antiepileptic drug can prevent futher acute seizures.
  • First-line treatment if intravenous access is available
    • Phenytoin
    • Sodium valproate
    • Phenobarbitone
  • Limited supporting evidence
    • Levetiracetam - children and adult
    • Lacosamide - adult

NOTE: Phenytoin has more adverse effects than sodium valproate (e.g. arrhythmias, infusion problems, hypotension).

Step 3: Transfer to intensive care unit and seek expert advice

  • For refractory status epilepticus.



Summary for Adults

Status Epilepticus Antiseizure Medication Management



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