Sudden unexpected death in epilepsy (SUDEP) | Epilepsy clinician handbook

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

Camfield 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.

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.

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.

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 SUDEP 1  (absences, myoclonic seizures alone have a very low risk of SUDEP).
  • Symptomatic aetiology

Long-term mortality in childhood onset epilepsy

  • 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 study 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.

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.
  • There are increasingly seizure detection devices available. 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. The ILAE (Epilepsia, 2020) recommends using clinically validated devices for automated detection of generalised tonic-clonic and focal to bilateral generalised tonic-clonic seizures, especially in unsupervised patients. Alarms need to follow with rapid intervention. Please see wearable devices for more details.
  • 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.
  • 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.

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:

References

Epilepsy syndromes
Family handbook
Clinical resources