Sudden unexpected death occurs in a small number of people who have epilepsy. People most at risk are those with severe frequent seizures. Preventing seizures as much as possible with treatment may reduce the risk of sudden death. A support group may be helpful if you are bereaved by an unexpected death of a loved one.
This leaflet is part of our series on epilepsy
What is sudden unexpected death in epilepsy (SUDEP)?
SUDEP is a term used when a person with epilepsy suddenly dies and the reason for the death is not known. For example, it is not due to injury or to drowning following or during a seizure and it is not due to a prolonged and severe seizure (status epilepticus).
What causes sudden unexpected death in epilepsy (SUDEP)?
The cause is not known. If a post-mortem examination is done on a person who dies of SUDEP, no abnormality is found to account for the death. There are various theories as to why a person with epilepsy may die suddenly. One theory is that a seizure may affect a part of the brain that controls heart or breathing function and so the heart and/or breathing just stop during a seizure.
How common is sudden unexpected death in epilepsy (SUDEP)?
The risk is small for most people with epilepsy. It is estimated to cause about 500 deaths per year in the UK. This sounds a lot; however, when you compare it to the number of people with epilepsy, it is quite rare. Of those who die from SUDEP, it is most common in people who have generalised tonic-clonic seizures, especially in young adults. The most important risk factors seem to be poor seizure control and seizures occurring during sleep.
Note: epilepsy is common. About 1 person in 30 in the UK develops epilepsy at some stage. Most people with epilepsy have a normal lifespan and do not die of SUDEP.
- In people with severe epilepsy (frequent and severe tonic-clonic seizures), it is estimated that about 1 in 200 dies of SUDEP each year.
- In people with mild idiopathic epilepsy (epilepsy of unknown cause), it is estimated that about 1 in 1,000 dies of SUDEP each year.
- In people who are in remission, the risk of SUDEP seems to be very low (negligible). The term in remission means that you have had seizures in the past but have none or very few at present. This is either because of treatment or because the epilepsy has settled down.
How can the risk be minimised?
If you have epilepsy, it may be possible to reduce the small risk of dying from sudden unexpected death in epilepsy (SUDEP) by:
- Preventing seizures as much as possible. This is usually by medication. In some people, surgery is used to prevent seizures when medication has not been successful in preventing seizures. However, in some cases it is not possible to stop seizures fully. See separate leaflet called Treatments for Epilepsy for details.
- Being aware of the potential risk of night-time seizures. Some people only have seizures at night when asleep (or have them more often at night). As the risk of SUDEP is still present even for night-time seizures, if possible, you should try to prevent these seizures as much as you can. This may mean a review of medication. But again, in some people it is not possible to prevent seizures fully.
Bereavement due to sudden unexpected death in epilepsy (SUDEP)
The sudden death of a loved one for any reason (such as due to SUDEP) is very upsetting and traumatic. If you have lost someone close due to this condition, it may be best to talk it through with your GP or with the GP of the affected person. It is a tragic event where usually nothing could have been done to prevent it from happening. Some people find that it helps to get information and help from a support group - details of some are given below.
Further help & information
Further reading & references
- Epilepsies: diagnosis and management; NICE Clinical Guideline (January 2012)
- Diagnosis and management of epilepsy in adults; Scottish Intercollegiate Guidelines Network - SIGN (2015)
- Epilepsy; NICE CKS, December 2014 (UK access only)
- Surges R, Thijs RD, Tan HL, et al; Sudden unexpected death in epilepsy: risk factors and potential pathomechanisms. Nat Rev Neurol. 2009 Sep;5(9):492-504. Epub 2009 Aug 11.
- Asadi-Pooya AA, Sperling MR; Clinical Features of Sudden Unexpected Death in Epilepsy. J Clin Neurophysiol. 2009 Aug 24.
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Tim Kenny
Dr Colin Tidy
Prof Cathy Jackson