Definition of Status Epilepticus
Status epilepticus is defined as continuous seizure activity lasting 5 minutes or longer, or recurrent seizures without return to baseline consciousness between episodes. 1, 2
Operational Definition for Clinical Practice
The 5-minute threshold is the current standard for initiating treatment protocols, replacing the older 30-minute definition, as recommended by the American Heart Association 1, 2
The traditional definition of 30 minutes of continuous seizure activity or serial seizures without full recovery of consciousness remains valid for epidemiological purposes, but is no longer the treatment trigger 3, 4, 5
Rationale for the 5-Minute Treatment Threshold
Seizures lasting beyond 5 minutes are unlikely to terminate spontaneously, making early intervention critical 3
The longer a seizure persists, the more difficult it becomes to control pharmacologically, creating a "therapeutic window" that narrows with time 3, 6
Waiting until 30 minutes to initiate treatment significantly increases the risk of permanent neurological impairment and mortality 7
Clinical Presentations
Status epilepticus encompasses several forms:
Generalized convulsive status epilepticus: Continuous or recurrent tonic-clonic seizures with impaired consciousness 5
Nonconvulsive status epilepticus: Prolonged altered mental status without obvious motor activity, requiring EEG for diagnosis 1, 8
Focal status epilepticus: Continuous focal seizure activity that may or may not impair consciousness 5
Critical Prognostic Factors
Three major determinants of outcome are seizure duration, patient age, and underlying etiology 1, 9
Overall mortality ranges from 5-22% in general cases, escalating to 65% in refractory status epilepticus 1, 8
Up to 5% of adults with epilepsy will experience at least one episode of status epilepticus in their lifetime 1, 2
Common Etiologies Requiring Immediate Investigation
- Metabolic derangements (hypoglycemia, hyponatremia) 1, 8, 7
- Central nervous system infections 2, 8
- Cerebrovascular events (ischemic stroke, hemorrhage) 2, 8, 9
- Subtherapeutic antiepileptic drug levels in known epilepsy patients 9
- Withdrawal syndromes (alcohol, benzodiazepines) 2, 8
- Hypoxia 1, 8
When to Activate Emergency Protocols
First responders and emergency medical services should be activated for:
- Any seizure lasting >5 minutes 2
- Multiple seizures without return to baseline mental status 2
- Failure to return to baseline within 5-10 minutes after seizure cessation 2
Special Considerations for EEG Monitoring
Emergent EEG is indicated for patients with persistent altered consciousness after apparent seizure termination to detect nonconvulsive status epilepticus 1, 8
EEG should be obtained in patients who received long-acting paralytics or are in drug-induced coma, as clinical seizure activity may be masked 1, 8