Sudden unexpected death in epilepsy (SUDEP) is a fatal complication of epilepsy.[1] It is defined as the sudden and unexpected, non-traumatic and non-drowning death of a person with epilepsy, without a toxicological or anatomical cause of death detected during the post-mortem examination.[2][3] While the mechanisms underlying SUDEP are still poorly understood, it is possibly the most common cause of death as a result of complications from epilepsy, accounting for between 7.5 to 17% of all epilepsy-related deaths[2] and 50% of all deaths in refractory epilepsy.[4][5] The causes of SUDEP seem to be multifactorial[2] and include respiratory, cardiac and cerebral factors, as well as the severity of epilepsy and seizures.[5] Proposed pathophysiological mechanisms include seizure-induced cardiac and respiratory arrests.[4] Instances of death as a result of prolonged seizures (status epilepticus) are not classified as SUDEP.[6]
Severity of seizures, increased refractoriness of epilepsy and presence of generalized tonic-clonic seizures:[4] the most consistent risk factor is an increased frequency of tonic–clonic seizures.[5]
Poor compliance.[4] Lack of therapeutic levels of anti-epileptic drugs, non-adherence to treatment regimens, and frequent changes in regimens are risk factors for sudden death.[5]
The mechanisms underlying SUDEP are not well understood but probably involve several pathophysiological mechanisms and circumstances. The most commonly involved are seizure-induced hypoventilation and cardiac arrhythmias but different mechanisms may be involved in different individuals, and more than one mechanism may be involved in any one individual.[9]
Cardiac factors: cardiac arrhythmias and other cardiac events are known to be involved in some cases of SUDEP.[5] Such arrhythmias are defined as ictal arrhythmias and include the ictal asystole which is a rare occurrence mostly in people that have temporal lobe epilepsy.[10][11]
Respiratory factors: impaired respiration and seizure induced pulmonary dysfunction as well as central apnea as a result of brain-stem respiratory centers suppression are known to play a role in some cases of SUDEP.[5]
Cerebral and autonomic nervous system dysregulation: cardiac arrhythmia and respiratory failure as a result of seizure related changes to brain function and dysfunction of the autonomic nervous system have been described in cases of SUDEP. These include cases of post-ictal generalized EEG suppression described as cerebral shutdown, but its significance remains unclear.[7]
Anti epileptic drugs: most evidence suggests that antiepileptic drugs are not associated with an increased risk for SUDEP, but rather reduce its incidence.[12] Some studies however indicate that some antiepileptic drugs such as lamotrigine and carbamazepine, may increase the risk of SUDEP in certain individuals.[13] It is unclear if this is because of the potential cardio-respiratory adverse effects such as lengthening of the QT interval and reduction of heart rate known to be associated with these drugs under certain circumstances,[9] or because a high drug dosage could be a surrogate marker for poor seizure control.[14]
The lack of generally recognized clinical recommendations available are a reflection of the dearth of data on the effectiveness of any particular clinical strategy,[9] but on the basis of present evidence, the following may be relevant:
Epileptic seizure control with the appropriate use of medication and lifestyle counseling is the focus of prevention.[5]
Reduction of stress, participation in physical exercises, and night supervision might minimize the risk of SUDEP.[2]
Knowledge of how to perform the appropriate first-aid responses to seizure by persons who live with epileptic people may prevent death.[5]
People associated with arrhythmias during seizures should be submitted to extensive cardiac investigation[2] with a view to determining the indication for on-demand cardiac pacing.[9]
Successful epilepsy surgery may reduce the risk of SUDEP, but this depends on the outcome in terms of seizure control.[9]
The use of anti suffocation pillows have been advocated by some practitioners to improve respiration while sleeping, but their effectiveness remain unproven because experimental studies are lacking.[5]
Providing information to individuals and relatives about SUDEP is beneficial.[7]
Approximately 50,000 people die each year in the USA from status epilepticus (prolonged seizures), SUDEP, and other seizure-related causes. SUDEP accounts for 8-17% of deaths in people with epilepsy.[15]
The risk of sudden death in young adults with epilepsy is increased 24-fold compared to the general population.[7]
SUDEP is the number one cause of epilepsy related death in people with pharmaco-resistant epilepsy.[7]
Children with epilepsy have a cumulative risk of dying suddenly of 7% within 40 years.[7]
In children, SUDEP accounts for 34% of all sudden deaths.[16]
Jump up ^Ryvlin, P; Nashef, L; Tomson, T (May 2013). "Prevention of sudden unexpected death in epilepsy: a realistic goal?". Epilepsia. 54 Suppl 2: 23–8. doi:10.1111/epi.12180. PMID23646967.
^ Jump up to: abcdefTerra, VC; Cysneiros, R; Cavalheiro, EA; Scorza, FA (Mar 2013). "Sudden unexpected death in epilepsy: from the lab to the clinic setting.". Epilepsy & behavior : E&B26 (3): 415–20. doi:10.1016/j.yebeh.2012.12.018. PMID23402930.
Jump up ^Tomson T, Nashef L, Ryvlin P (November 2008). "Sudden unexpected death in epilepsy: current knowledge and future directions". Lancet Neurology7 (11): 1021–31. doi:10.1016/S1474-4422(08)70202-3. PMID18805738.
Jump up ^Schuele, SU; Bermeo, AC; Alexopoulos, AV; Locatelli, ER; Burgess, RC; Dinner, DS; Foldvary-Schaefer, N (Jul 31, 2007). "Video-electrographic and clinical features in patients with ictal asystole.". Neurology69 (5): 434–41. doi:10.1212/01.wnl.0000266595.77885.7f. PMID17664402.
Jump up ^Ryvlin, P; Cucherat, M; Rheims, S (Nov 2011). "Risk of sudden unexpected death in epilepsy in patients given adjunctive antiepileptic treatment for refractory seizures: a meta-analysis of placebo-controlled randomised trials.". Lancet neurology10 (11): 961–8. doi:10.1016/S1474-4422(11)70193-4. PMID21937278.
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