Sudden unexpected death in epilepsy (SUDEP)

Overview

  • SUDEP: Sudden unexpected witnessed or unwitnessed, non-traumatic and non-drowning death occurring in benign circumstances, in an individual with epilepsy, with or without evidence of a seizure and excluding documented status, in which post-mortem exam does not reveal cause of death.
  • Probable: same definition as above, but without post-mortem.
  • Possible: competing cause of death present.1

 

  • 1. Nashef et al. (2012). Unifying the definitions of sudden unexpected death in epilepsy. Epilepsia, 53(2): 227-233.

Incidence

  • 0.09-2.3 / 1000 patient-years: Across all ages in community-based studies.
  • 9.3 / 1000 patient-years: In epilepsy surgical referrals.

Camfield 1 offered a paediatric perspective of epilepsy. In a study of children with epilepsy where a cohort was followed for twenty years, he concluded:

  • For those with severe neurological handicap, death rate may approach 25% over the next 20 years, but death is related to neurological disability, not seizures.

In more recent literature, death in children with epilepsy has again been related to "complicated epilepsy", that is, those with associated neuro-disability.2

The incidence of SUDEP in children has been re-evaluated utilising cohorts from Ontario Canada and Sweden. The overall incidence was 1.1/1000 patient-years, similar to adult populations.3  4

The North American SUDEP Registry (Neurology, 2019) published that SUDEP affects the full spectrum of epilepsies. 27% were aged < 16 years. Three children with Childhood Epilepsy and Centrotemporal Spikes were included in the cohort.5

  • 1. Camfield. P. & Camfield, C. (2005). Sudden Unexpected Death in People with Epilepsy: A Pediatric Perspective.Sem Ped Neurol, 12:10-14.
  • 2. Berg et al. (2013). Mortality Risks in New-Onset Childhood Epilepsy. Pediatrics, 132:124-131.
  • 3. Sveinsson et al. (2017). The incidence of SUDEP. A nationwide population-based cohort study. Neurology, 89, 170-177.
  • 4. Keller at al. (2018). Incidence of sudden unexpected death in epilepsy in children is similar to adults. Neurology, 91(2), e107-e111.
  • 5. Neurology 93, 3, July 16, 2019

Risk factors

  • Onset of epilepsy <16 years
  • Epilepsy > 15 years
  • Frequency of generalised tonic-clonic seizures
  • Nocturnal seizures
  • Patients who sleep alone and have generalised tonic-clonic seizures are at particular risk for SUDEP1 
  • Symptomatic aetiology

 
Long-term mortality in childhood-onset epilepsy2

  • Cumulative risk of unexplained death in childhood-onset epilepsy was 7% at 40 years.
  • Among subjects with idiopathic or cryptogenic epilepsy, there were no unexplained deaths < 14 years.
  • Median age of SUDEP: 25 years (4-49).

In a study3 of SUDEP recorded in monitoring units, all deaths were nocturnal and had a lack of supervision. The majority were in the prone position; medication had been decreased or ceased. The mechanism of death was cardiorespiratory with terminal apnoea followed by cardiac arrest.

  • 1. Sveinsson et al (2020). Clinical risk factors in SUDEP. A nationwide population-based case-control study. Neurology: 94(4): e419-e429.
  • 2. Sillanpaa et al. (2010). Long-Term mortality in Childhood-Onset Epilepsy. N Eng J Med, 363: 2522-9.
  • 3. Ryvlin et al. (2013). Incidence and mechanisms of cardiorespiratory arrests in epilepsy monitoring units (MORTEMUS): a retrospective study. Lancet Neurol,12: 966-77.

Prevention

  • Seizure control is the most effective way to prevent epilepsy-related deaths, in particular SUDEP. 
  • Compliance is critical.
  • Nocturnal Supervision (e.g. sharing a bedroom, using a listening device) may reduce the likelihood of SUDEP. 1  2
  • There are increasingly available seizure detection devices based on a variety of biomarkers. With improved technology this is a rapidly moving field. Although there are false positives and false negatives, there is increasing data that certain wearable devices can frequently detect generalised tonic-clonic seizures.
  • As a sizeable minority of SUDEP occurred in patients thought to be treatment responsive and/or with benign epilepsies (Publication: North American SUDEP registry - Neurology, 2019), the authors emphasised the importance of SUDEP education across the spectrum of epilepsy severities.

Recommendations

  • The NICE Guidelines advise that information on SUDEP should be included in the education given to patients and carers to show why preventing seizures is important. Tailored information on the patient’s relative risk of SUDEP should be part of the counselling checklist for children, young people and adults with epilepsy and their families and/or carers.
  • There is literature to support that parents/families/carers want information and that doctors frequently do not provide it.3
  • If the risk is low, the conversation is often reassuring. If the risk is high, the specific intent is to encourage compliance and to achieve better seizure control.

When to discuss SUDEP?

It is important to recognise barriers to disclosure: comfort, knowledge, opportunity.

Literature supports information sharing with families at the time of diagnosis. It is recognised that families want information. It also enables discussion of potential risk modification. 

There are additional opportunities to reinforce the information:

  • Following questions by family
  • Intractable epilepsy
  • Poor compliance
  • Surgical referral
  • Drug discontinuation or lifestyle change
  • When the patient has unaddressed fear regarding risk.
  • 1. Langan et al. (2005). Case-control study of SUDEP. Neurology, 64:1131-33)
  • 2. Van der Lende et al. Nocturnal supervision and SUDEP risk at different epilepsy care settings. 2018. Neurology, 91 (16)
  • 3. Gayatri et al. (2010). Parental and physician beliefs regarding the provision and content of written sudden unexpected death in epilepsy (SUDEP) information. Epilepsia; 51: 777-782.

Resources

AES Position Statement on SUDEP Counselling:

Practice Guideline Summary:

SUDEP Education Video:

  • "Making Sense of SUDEP"  featuring Dr Elizabeth Donner, Director of the Comprehensive Epilepsy Program at The Hospital for Sick Children Toronto, Canada.  

Other resources:

 

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Information last reviewed: 14/01/2021.

References

  • Nashef et al. (2012). Unifying the definitions of sudden unexpected death in epilepsy. Epilepsia, 53(2): 227-233.
  • Camfield. P. & Camfield, C. (2005). Sudden Unexpected Death in People with Epilepsy: A Pediatric Perspective.Sem Ped Neurol, 12:10-14.
  • Sillanpaa et al. (2010). Long-Term mortality in Childhood-Onset Epilepsy. N Eng J Med, 363: 2522-9.
  • Ryvlin et al. (2013). Incidence and mechanisms of cardiorespiratory arrests in epilepsy monitoring units (MORTEMUS): a retrospective study. Lancet Neurol,12: 966-77.
  • Langan et al. (2005). Case-control study of SUDEP. Neurology, 64:1131-33)
  • Gayatri et al. (2010). Parental and physician beliefs regarding the provision and content of written sudden unexpected death in epilepsy (SUDEP) information. Epilepsia; 51: 777-782.