Status epilepticus

Status epilepticus (SE) is a life-threatening neurologic condition defined as 5 or more minutes of either continuous seizure activity or repetitive seizures without regaining consciousness.

Generalized convulsive SE in both its subtle and overt subtypes constitutes the most frequent variant.

Diagnosis of nonconvulsive SE can be difficult, but recognition is crucial because rapid termination helps prevent serious brain injury, especially in patients with impaired consciousness.

In most cases, treatment must precede any thorough investigation and must be initiated as soon as SE is suspected.

Treatment involves a stepwise approach with pharmacotherapy aimed at aborting the clinical and electrographic seizures.

Carries a high mortality rate and may cause serious complications if not promptly treated.

Generalized convulsive and nonconvulsive SE are neurologic and medical emergencies defined as 5 or more minutes of either continuous seizure activity or repetitive seizures with no intervening recovery of consciousness.[1]Lowenstein DH, Bleck T, Macdonald RL. It's time to revise the definition of status epilepticus. Epilepsia. 1999 Jan;40(1):120-2. http://www.ncbi.nlm.nih.gov/pubmed/9924914?tool=bestpractice.com [2]Brophy GM, Bell R, Claassen J, et al; Neurocritical Care Society Status Epilepticus Guideline Writing Committee. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012 Aug;17(1):3-23. http://www.ncbi.nlm.nih.gov/pubmed/22528274?tool=bestpractice.com ​​ 

In the 2017 International League Against Epilepsy (ILAE) classification of seizures, convulsive seizures are termed "focal to bilateral tonic-clonic" seizures if they are focal in onset, and "generalized tonic-clonic" if they are generalized in onset.[3]Fisher RS, Cross JH, French JA, et al. Operational classification of seizure types by the International League Against Epilepsy: position paper of the ILAE Commission for Classification and Terminology. Epilepsia. 2017 Apr;58(4):522-30. https://onlinelibrary.wiley.com/doi/full/10.1111/epi.13670 http://www.ncbi.nlm.nih.gov/pubmed/28276060?tool=bestpractice.com As the time of onset of a seizure may be unknown when a patient presents to medical attention in SE and as both types of convulsive SE are treated identically, for the purposes of this topic, the categories "generalized convulsive SE" and "nonconvulsive SE" will be used.

SE that does not respond to adequate first- and second-line treatment is termed refractory SE (RSE). If RSE is treated with intravenous anesthetic agents for 24 hours or more and SE continues or recurs on weaning of the agent, it is termed super-RSE (SRSE).[4]Ochoa JG, Dougherty M, Papanastassiou A, et al. Treatment of super-refractory status epilepticus: a review. Epilepsy Curr. 2021 Mar 10;21(6):1535759721999670. https://pmc.ncbi.nlm.nih.gov/articles/PMC8652329 http://www.ncbi.nlm.nih.gov/pubmed/33719651?tool=bestpractice.com New-onset RSE (NORSE) is a rare presentation characterized by de novo onset of RSE without an identifiable acute or active structural, toxic, or metabolic cause.[5]Wickstrom R, Taraschenko O, Dilena R, et al. International consensus recommendations for management of new onset refractory status epilepticus (NORSE) including febrile infection-related epilepsy syndrome (FIRES): summary and clinical tools. Epilepsia. 2022 Aug 11;63(11):2827-39. https://pmc.ncbi.nlm.nih.gov/articles/PMC9826478 http://www.ncbi.nlm.nih.gov/pubmed/35951466?tool=bestpractice.com [6]Tharmaraja T, Ho JSY, Neligan A, et al. The etiology and mortality of new-onset refractory status epilepticus (NORSE) in adults: a systematic review and meta-analysis. Epilepsia. 2023 May;64(5):1113-24. http://www.ncbi.nlm.nih.gov/pubmed/36727541?tool=bestpractice.com ​ Febrile infection-related epilepsy syndrome (FIRES) in children is a subset of NORSE.​​​​