Status epilepticus is "prolonged seizure or seizures repeated frequently enough to prevent recovery between episodes occurring over a period of 20-30 minutes. The most common subtype is generalized tonic-clonic status epilepticus, a potentially fatal condition associated with neuronal injury and respiratory and metabolic dysfunction. Nonconvulsive forms include petit mal status and complex partial status, which may manifest as behavioral disturbances. Simple partial status epilepticus consists of persistent motor, sensory, or autonomic seizures that do not impair cognition (see also epilepsia partialis continua). Subclinical status epilepticus generally refers to seizures occurring in an unresponsive or comatose individual in the absence of overt signs of seizure activity."
Status epilepticus may be classified by either the type of seizure or the time course.
Classification by type of seizure
Generalized status epilepticus
Nonconvulsive status epilepticus (NCSE)
Nonconvulsive status epilepticus (NCSE) is a "term used to denote a range of conditions in which electrographic seizure activity is prolonged and results in nonconvulsive clinical symptoms."
|Emergency care (age > 15)||25 consecutive patients with mental status changes without obvious cause||8%|
|Coma (all ages)||236 consecutive cases in retrospective review||8%|
|Intensive care (all ages)||570 patients whose doctors requested continuous EEG monitoring for various reasons||18%|
|After the control of convulsive status epilepticus||164 consecutive patients||48% (14% were true complex partial NCSE)|
NCSE is an important cause of altered cognition, acute confusion, or altered mental status according to a systematic review. One third of elderly patients with nonconvulsive status have a history of epilepsy.. NCSE can happen in many settings including Stage 5 chronic kidney disease.
Continuous EEG monitoring for more than 24 hours may be needed to detect NCSE.
- Petit mal status
Petit mal status may cause behavioral disturbances.
- Complex partial status
Complex partial status may cause behavioral disturbances.
- Simple partial status
Simple partial status (Epilepsia partialis continua) does not impair cognition.
- Subclinical status epilepticus
In subclinical status epilepticus the patient may be unresponsive or comatose and without overt signs of seizures.
Classification by time course
Below is a classification based on the time course of the seizure(s).
Premonitory phase is the "period during which seizures became increasingly frequent or severe but the condition did not meet the definition of status epilepticus."
Early status epilepticus
Early status is the "first 30 minutes of seizure activity."
Established status epilepticus
Established status epilepticus is a "condition with either more than 30 minutes of continuous seizure activity or two or more sequential seizures without recovery of full consciousness between the seizures".
Refractory status epilepticus
If seizure activity remains uncontrolled for one to two hours, in spite of first-line treatment, then the participant is considered to be in refractory status epilepticus
The patients with nonconvulsive status epilepticus may only show atypical triphasic waves on their electroencephalogram.
"Lorazepam is better than diazepam or phenytoin alone for cessation of seizures" according to a meta-analysis of randomized controlled trials by the Cochrane Collaboration. One specific randomized controlled trial used lorazepam 2 mg intravenously with a repeat dose after 4 minutes if needed.
- Anonymous (2022), Status epilepticus (English). Medical Subject Headings. U.S. National Library of Medicine.
- Walker M, Cross H, Smith S, et al (September 2005). "Nonconvulsive status epilepticus: Epilepsy Research Foundation workshop reports". Epileptic Disord 7 (3): 253–96. PMID 16162436.
- Bautista RE, Godwin S, Caro D (February 2007). "Incorporating abbreviated EEGs in the initial workup of patients who present to the emergency room with mental status changes of unknown etiology". J Clin Neurophysiol 24 (1): 16–21. DOI:10.1097/WNP.0b013e318030e8cb. PMID 17277572. Research Blogging.
- Towne AR, Waterhouse EJ, Boggs JG, et al (January 2000). "Prevalence of nonconvulsive status epilepticus in comatose patients". Neurology 54 (2): 340–5. PMID 10668693.
- Claassen J, Mayer SA, Kowalski RG, Emerson RG, Hirsch LJ (May 2004). "Detection of electrographic seizures with continuous EEG monitoring in critically ill patients". Neurology 62 (10): 1743–8. PMID 15159471.
- DeLorenzo RJ, Waterhouse EJ, Towne AR, et al (August 1998). "Persistent nonconvulsive status epilepticus after the control of convulsive status epilepticus". Epilepsia 39 (8): 833–40. PMID 9701373.
- Beyenburg S, Elger CE, Reuber M (2007). "Acute Confusion or Altered Mental State: Consider Nonconvulsive Status Epilepticus". Gerontology 53 (6): 150–158. DOI:10.1159/000106829. PMID 17684419. Research Blogging.
- Bottaro FJ, Martinez OA, Pardal MM, Bruetman JE, Reisin RC (2007). "Nonconvulsive status epilepticus in the elderly: a case-control study". Epilepsia 48 (5): 966–72. DOI:10.1111/j.1528-1167.2007.01033.x. PMID 17381437. Research Blogging.
- Iftikhar S, Dahbour S, Nauman S (October 2007). "Nonconvulsive status epilepticus: high incidence in dialysis-dependent patients". Hemodial Int 11 (4): 392–7. DOI:10.1111/j.1542-4758.2007.00206.x. PMID 17922733. Research Blogging.
- Haffey S, McKernan A, Pang K (July 2004). "Non-convulsive status epilepticus: a profile of patients diagnosed within a tertiary referral centre". J. Neurol. Neurosurg. Psychiatr. 75 (7): 1043–4. PMID 15201368. PMC 1739117.
- Ghofrani M, Mahvelati F, Tonekaboni H (May 2007). "Headache as a sole manifestation in nonconvulsive status epilepticus". J. Child Neurol. 22 (5): 660–2. DOI:10.1177/0883073807303252. PMID 17690080. Research Blogging.
- Prasad K, Al-Roomi K, Krishnan PR, Sequeira R (2005). "Anticonvulsant therapy for status epilepticus". Cochrane Database Syst Rev (4): CD003723. DOI:10.1002/14651858.CD003723.pub2. PMID 16235337. Research Blogging.
- Kaya D, Bingol CA (2007). "Significance of atypical triphasic waves for diagnosing nonconvulsive status epilepticus". Epilepsy Behav 11 (4): 567–77. DOI:10.1016/j.yebeh.2007.07.014. PMID 17942373. Research Blogging.
- Alldredge BK, Gelb AM, Isaacs SM, et al (2001). "A comparison of lorazepam, diazepam, and placebo for the treatment of out-of-hospital status epilepticus". N. Engl. J. Med. 345 (9): 631–7. PMID 11547716.