Status epilepticus: Wikis

  
  

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Status epilepticus
Classification and external resources
ICD-10 G41.
ICD-9 345.3
eMedicine emerg/554
MeSH D013226

Status epilepticus (SE) is a life-threatening condition in which the brain is in a state of persistent seizure. Definitions vary, but traditionally it is defined as one continuous unremitting seizure lasting longer than 30 minutes [1], or recurrent seizures without regaining consciousness between seizures for greater than 30 minutes (or shorter with medical intervention). It is always considered a medical emergency. There is some evidence that 5 minutes is sufficient to damage neurons and that seizures are unlikely to self-terminate by that time. First aid guidelines for seizures state that, as a rule, an ambulance should be called for seizures lasting longer than 5 minutes (if this is the patient's first seizure episode and there were no known precipitating factors, or if SE happens to an epileptic whose seizures were previously absent or well-controlled for a considerable time period, then that step can be taken before that point).[2] The mortality rate of status epilepticus is very high (at least 20%), especially if treatment is not intiated quickly. However, with optimal neurological care and a good prognosis, the patient (even some epileptics) in otherwise good health can survive with minimal or no brain damage, and can even avoid future seizures.[3]

Contents

Causes

Only 25 percent of people who experience seizures or status epilepticus have epilepsy.[3]

  • Stroke[3]
  • Hemorrhage[3]
  • Intoxicants[3] or adverse reactions to drugs.
  • Insufficient dosage of a medication already prescribed to the patient. Such causes of this include:
    • Forgetfulness on the part of the patient in taking scheduled doses, or failure to take doses at the scheduled times
    • Dislike of the medication or its side effects
    • Patient's rationing of the medication. This is usually due to patient's difficulty in affording medication, or temporary or permanent lack of access.
    • Failure to maintain a therapeutic level following a change in a patient's physiological needs. This may be the result of a patient growing (into adolescence or adulthood), gaining weight, pregnancy, or childbirth.
  • Sudden withdrawal from a seizure medication. Such causes include:
    • Sudden lack of access to medication due to unexpected circumstances
    • Lack of ability of patient to communicate medication needs to others, leading to absence of doses
    • Physician's decision to discontinue medication
  • Consumption of alcoholic beverages while on an anticonvulsant, or alcohol withdrawal. For this among other reasons, most patients who have active seizure disorders or who are on anticonvulsants are advised to altogether avoid consuming alcohol.
  • Dieting or fasting while on an anticonvulsant. Those with epilepsy or who are on anticonvulsants are advised to consult with their physicians prior to dieting or fasting.
  • Consuming certain food products that interact badly with an anticonvulsant (rare)
  • Starting on a new medication that reduces the effectiveness of the anticonvulsant
  • Developing a resistance to an anticonvulsant already being used
  • Injury to the patient. This may be the result of a sports injury, motor vehicle accident, fall, physical abuse, or other injury that affects the brain. Though such injuries may trigger a seizure in anyone, those with a known seizure disorder are more susceptible.
  • Gastroenteritis while on an anticonvulsant. This is because the digestive system may force out the anticonvulsant, thereby rendering the body with a lack of protection.
  • Developing a new, unrelated condition in which seizures are coincidentally also a symptom, but are not controlled by an anticonvulsant already used
  • Metabolic disturbances—such as affected kidney and liver[3]

This condition may also occur as the first known seizure in new epileptics, accounting for about 10% of cases. In non-epileptics, causes may include:

[4]

Occurrence

In the United States, approximately 40 cases of status epilepticus occur annually out of every 100,000 members of the population. This includes about 10-20% of all first seizures[5].

Variants

Status epilepticus can be divided into two categories—convulsive and nonconvulsive, the latter of which is underdiagnosed[citation needed].

Convulsive

Epilepsia partialis continua is a variant involving hour, day, or even week-long jerking. It is a consequence of vascular disease, tumours, or encephalitis, and is drug-resistant.

Generalized myoclonus is commonly seen in comatose patients following CPR and is seen by some as an indication of catastrophic damage to the neocortex.[6]

Nonconvulsive

Complex partial status epilepticus, or CPSE, and absence status epilepticus are rare forms of the condition which are marked by nonconvulsive seizures. In the case of CPSE, the seizure is confined to a small area of the brain, normally the temporal lobe. But the latter, absence status epilepticus, is marked by a generalised seizure affecting the whole brain, and an EEG is needed to differentiate between the two conditions. This results in episodes characterized by a long-lasting stupor, staring and unresponsiveness.

Treatments

Diazepam that can be inserted rectally is often prescribed to caregivers of epileptics. This enables treatment of multiple seizures prior to being able to seek medical care.

Benzodiazepines

Shortly after it was introduced in 1963, diazepam became the first choice for SE. Even though other benzodiazepines such as clonazepam were useful, diazepam was relied upon almost exclusively. This began to change in 1975 with a preliminary study on lorazepam conducted by Waltregny and Dargent, who found that its pharmacological effects were longer lasting than those of an equal dose of diazepam.[7] This meant it did not have to be repeatedly injected like diazepam,[8] the effects of which would wear off 5–15 minutes later in spite of its 30-hour half-life (due to extensive redistribution of diazepam outside the vascular compartment as diazepam is highly lipid soluble). It has also been found that patients who were first tried on diazepam were much more likely to require endotracheal tubing than patients who were first tried on phenobarbital, phenytoin,[9] or lorazepam.[10]

Today, the benzodiazepine of choice is lorazepam for initial treatment due to its long (2–8 hour) duration of action and rapid onset of action, thought to be due to its high affinity for GABA receptors and to its low lipid solubility which causes it to remain in the vascular compartment. If lorazepam is not available, or intravenous access is not possible, then diazepam should be given.[11] Particularly in children another, increasingly popular treatment choice is buccal and intranasal midazolam, which can be given into the side of the mouth.[12] Sometimes, the failure of lorazepam alone is considered to be enough to classify a case of SE as refractory.

Phenytoin and fosphenytoin

Phenytoin was once another first-line therapy,[13] although the prodrug fosphenytoin can be administered three times as fast and with far fewer injection site reactions. If these or any other hydantoin derivatives are used, then cardiac monitoring is a must if they are administered intravenously. Because the hydantoins take 15–30 minutes to work, a benzodiazepine or barbiturate is often co-administered. Because of diazepam's short duration of action, they were often administered together anyway.

Carbamazepine and valproate

Carbamazepine and valproate have replaced phenytoin as first line choices for treatment of status epilepticus.[14]

Barbiturates

Before the benzodiazepines were invented, there were the barbiturates, which are still used today if benzodiazepines or the hydantoins are not an option. These are used to induce a barbituric coma. The barbiturate most commonly used for this is phenobarbital. Thiopental or pentobarbital may also be used for that purpose if the seizures have to be stopped immediately or if the patient has already been compromised by the underlying illness or toxic/metabolic-induced seizures; however, in those situations, thiopental is the agent of choice.

The failure of phenobarbital therapy does not preclude the success of a lengthy comatose state induced by a stronger barbiturate such as secobarbital. Such was the case for Ohori, Fujioka, and Ohta ca. 1998, when they induced a 10-month long coma (or "anesthesia" as they called it) in a 26-year-old woman suffering from refractory status epilepticus secondary to viral encephalitis and then tapered her off the secobarbital very slowly while using zonisamide at the same time.[15]

General anesthetics

If this proves ineffective or if barbiturates cannot be used for some reason, then a general anesthetic such as propofol[16] is tried; sometimes it is used second after the failure of lorazepam.[17] This also means putting the patient on artificial respiration. Propofol has been shown to be effective in suppressing the jerks seen in myoclonus status epilepticus, but as of 2002, there have been no cases of anyone going into myoclonus status epilepticus, undergoing propofol treatment, and then not dying anyway.[18]

Lidocaine

The use of lidocaine in status epilepticus was first reported in 1955 by Bernhard, Boem and Hojeberg.[19] Since then, it has been used in cases refractory to phenobarbital, diazepam, and phenytoin, and has been studied as an alternative to barbiturates and general anesthetics.[20][21] Lidocaine is a sodium channel blocker and has been used where sodium channel dysfunction was suspected.[22] However, in some studies, it was either ineffective or even harmful for most patients.[23] The last is not so surprising in light of the fact that lidocaine has been known to cause seizures in humans and laboratory animals at doses greater than 15 µg/mL[24] or 2–3 mg/kg.[25]

Expected outcome

About one in five, a total of 42,000 annually in the United States, will die within 30 days of having an initial status epilepticus seizure. The great majority of these people have an underlying brain condition causing their status seizure such as brain tumor, brain infection, brain trauma or stroke. However, people with diagnosed epilepsy who have a status seizure also have an increased risk of death.[26]

References

  1. ^ Annals of Emerg Med 2004; 43(5): 605-625
  2. ^ http://www.epilepsyfoundation.org/about/types/types/statusepilepticus.cfm
  3. ^ a b c d e f g h i j Stasiukyniene, V.; Pilvinis, V.; Reingardiene, D.; Janauskaite, L. (2009). "[Epileptic seizures in critically ill patients]". Medicina (Kaunas) 45 (6): 501-7. PMID 19605972. 
  4. ^ name="soman">McDonough, John H.; A. Benjamin, Joseph D. McMonagle, Thomas Rowland, Shih Tsung-Ming (February 2004). "Effects of fosphenytoin on nerve agent-induced status epilepticus". Drug and Chemical Toxicology 27 (1): 27–39. doi:10.1081/DCT-120027895. PMID 15038246. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&list_uids=15038246&dopt=ExternalLink. 
  5. ^ http://www.answers.com/topic/status-epilepticus
  6. ^ Wijdicks, Eelco F. M.; Parisi JE, Sharbrough FW (February 1994). "Prognostic value of myoclonus status in comatose survivors of cardiac arrest". Annals of Neurology 35 (2): 239–43. doi:10.1002/ana.410350219. PMID 8109907. 
  7. ^ Waltregny, Alain; Jérôme Dargent (September/October 1975). "Preliminary study of parenteral lorazepam in status epilepticus". Acta Neurologica Belgica 75 (5): 219–29. PMID 3939. 
  8. ^ Walker, JE; RW Homan, MR Vasko, IL Crawford, RD Bell, WG Tasker (September 1979). "Lorazepam in status epilepticus". Annals of Neurology 6 (3): 207–13. doi:10.1002/ana.410060305. PMID 43112. 
  9. ^ Orr, Richard A.; Robert J. Dimand, Shekhar T. Venkataraman, Valerie A. Karr, Kathleen J. Kennedy (September 1991). "Diazepam and intubation in emergency treatment of seizures in children". Annals of Emergency Medicine 20 (9): 1009–13. doi:10.1016/S0196-0644(05)82981-6. PMID 1877765. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WB0-4G82KTB-G&_coverDate=09%2F30%2F1991&_alid=434858892&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6696&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=fab697f11c8e05b7fe0405b1d34a6f7d. 
  10. ^ Appleton, Richard; A. Sweeney, Imti Choonara, Joan Robson, Elizabeth Molyneux. (August 1995). "Lorazepam versus diazepam in the acute treatment of epileptic seizures and status epilepticus". Developmental Medicine and Child Neurology 37 (8): 682–8. PMID 7672465. 
  11. ^ Pang, Trudy; Lawrence J. Hirsch (July 2005). "Treatment of Convulsive and Nonconvulsive Status Epilepticus". Current Treatment Options in Neurology 7 (4): 247–259. doi:10.1007/s11940-005-0035-x. PMID 15967088. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&list_uids=15967088&dopt=ExternalLink. 
  12. ^ Walker, DM.; Teach, SJ. (Jun 2006). "Update on the acute management of status epilepticus in children.". Curr Opin Pediatr 18 (3): 239-44. doi:10.1097/01.mop.0000193306.55635.24. PMID 16721142. 
  13. ^ Beran, RG. (Apr 2008). "An alternative perspective on the management of status epilepticus.". Epilepsy Behav 12 (3): 349-53. doi:10.1016/j.yebeh.2007.12.013. PMID 18262847. 
  14. ^ Beran, RG. (Apr 2008). "An alternative perspective on the management of status epilepticus.". Epilepsy Behav 12 (3): 349-53. doi:10.1016/j.yebeh.2007.12.013. PMID 18262847. 
  15. ^ Ohori, Nobuhira; Fujioka Y, Ohta M. (May 1998). "[Experience in managing refractory status epilepticus caused by viral encephalitis under long-term anesthesia with barbiturate: a case report]". Rinsho Shinkeigaku 38 (5): 474–7. PMID 9806000.  (Japanese)
  16. ^ Pourrat, X; JM Serekian, D Antier, J. Grassin (June 9, 2001). "[Generalized tonic-clonic status epilepticus: therapeutic strategy]". Presse Médicale 30: 1031–6. PMID 11433696.  (French).
  17. ^ Marik, Paul E.; Joseph Varon (2004). "The management of status epilepticus". Chest 126 (2): 582–91. doi:10.1378/chest.126.2.582. PMID 15302747. http://www.chestjournal.org/cgi/content/full/126/2/582. 
  18. ^ Wijdicks, Eelco F.M. (July 2002). "Propofol in myoclonus status epilepticus in comatose patients following cardiac resuscitation". Journal of Neurology Neurosurgery and Psychiatry 73 (1): 94–5. doi:10.1136/jnnp.73.1.94. PMID 12082068. http://jnnp.bmjjournals.com/cgi/content/full/73/1/94. 
  19. ^ Bernhard, CG; Bohm E, Hojeberg S (August 1955). "A new treatment of status epilepticus; intravenous injections of a local anesthetic (lidocaine)". AMA Archives of Neurology and Psychiatry 74 (2): 208–14. PMID 14397899. 
  20. ^ Aggarwal, Praveen; Jyoti Prakash Wali (May 1993). "Lidocaine in refractory status epilepticus: a forgotten drug in the emergency department". American Journal of Emergency Medicine 11 (3): 243–4. doi:10.1016/0735-6757(93)90135-X. PMID 93257009. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&list_uids=8489668&dopt=ExternalLink. 
  21. ^ Sugiyama, N; Hamano S, Mochizuki M, Tanaka M, Eto Y (November 2004). "[Efficacy of lidocaine on seizures by intravenous and intravenous-drip infusion]". No to Hattatsu 36 (6): 451–4. PMID 15560386.  (Japanese)
  22. ^ Sawaishi Yukio; Yano Tamami, Enoki Masamichi, and Takada Goro (February 2002). "Lidocaine-dependent early infantile status epilepticus with highly suppressed EEG". Epilepsia 43 (2): 201–4. doi:10.1046/j.1528-1157.2002.25301.x. PMID 11903470. 
  23. ^ Tanabe Takuya; Suzuki Shuuhei, Shimakawa Shuichi, Yamashiro Kuniteru, Tamai Hiroshi (January 1999). "Problems of intravenous lidocaine treatment in status epilepticus or clustering seizures in childhood". No to Hattatsu 31 (1): 14–20. PMID 10025129.  (Japanese)
  24. ^ DeToledo, John C. (June 2000). "Lidocaine and Seizures". Therapeutic Drug Monitoring 22 (3): 320–322. doi:10.1097/00007691-200006000-00014. PMID 10850400. 
  25. ^ Steven C. Schachter. "Lidocaine". epilepsy.com/professionals. http://professionals.epilepsy.com/page/local_lidocaine.html.  Adapted from: Najjar S, Devinsky O, Rosenberg AD, et al. (2002). "Procedures in epilepsy patients". in ed. Ettinger AB and Devinsky O. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann. pp. 499–513. ISBN 0-7506-7241-2. 
  26. ^ http://www.epilepsyfoundation.org/about/types/types/statusepilepticus.cfm

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