What is the definition of status epilepticus?

Definition of Status Epilepticus

Status epilepticus is defined as unremitting convulsive seizure activity lasting 20 minutes or more or intermittent seizures without regaining full consciousness between episodes. 1

Traditional Definition and Evolution

• The traditional definition of status epilepticus has been a continuous seizure lasting 30 minutes or more, or recurrent seizures without recovery of consciousness between episodes 2
• More recent clinical guidelines have proposed shorter timeframes for intervention, with some suggesting that generalized convulsive seizures lasting 5 minutes should prompt treatment as status epilepticus 1
• The International League Against Epilepsy (ILAE) 2015 definition describes status epilepticus as resulting from either failure of the mechanisms responsible for seizure termination or from the initiation mechanisms leading to abnormally prolonged seizures 3

Types of Status Epilepticus

• Status epilepticus can be classified as:
  • Convulsive (focal or generalized) 4
  • Nonconvulsive (absence or partial complex) 4
• Generalized convulsive status epilepticus encompasses a spectrum from repeated overt generalized tonic-clonic seizures to subtle convulsive movements in a profoundly comatose patient 2

Clinical Significance and Mortality

• Status epilepticus represents a medical and neurological emergency with significant morbidity and mortality 5
• Mortality rates range from 10-20% in general cases 4, 6
• Up to 5% of adults with epilepsy will experience at least one episode of status epilepticus in their lifetime 1
• The three major determinants of prognosis are:
  • Duration of status epilepticus
  • Patient age
  • Underlying cause 6

EEG Patterns in Status Epilepticus

• A predictable sequence of progressive EEG changes occurs during untreated status epilepticus, including:
  • Discrete electrographic seizures
  • Waxing and waning patterns
  • Continuous ictal activity
  • Continuous activity with flat periods
  • Periodic epileptiform discharges on a relatively flat background 2

Etiologies

• Common causes include:
  • Cerebrovascular disorders
  • Brain trauma
  • Infections
  • Low antiepileptic drug levels in patients with epilepsy 6
• Other potential causes requiring investigation:
  • Hypoglycemia
  • Hyponatremia
  • Hypoxia
  • Drug toxicity
  • Systemic or CNS infection
  • Ischemic stroke
  • Intracerebral hemorrhage
  • Withdrawal syndromes 1

Clinical Implications

• Status epilepticus requires immediate treatment as it is a life-threatening condition 7
• First aid providers should activate EMS for seizures lasting >5 minutes, multiple seizures without return to baseline mental status, or if the person doesn't return to baseline within 5-10 minutes after seizure activity stops 1
• The condition is dynamic, progressing from overt to increasingly subtle clinical manifestations if untreated 2

Treatment Approach

• First-line treatment involves benzodiazepines, with lorazepam being a common choice 8, 4
• Second-line options include intravenous phenytoin, fosphenytoin, or valproate 1, 7
• For refractory cases, levetiracetam, propofol, or barbiturates may be used 1, 7
• Simultaneous investigation and treatment of underlying causes is essential 1, 7

Status epilepticus represents a critical neurological emergency requiring prompt recognition and aggressive treatment to prevent neurological morbidity and mortality.