What Is SUDEP?

Reviewed by: HU Medical Review Board | Last reviewed: November 2021

SUDEP stands for sudden unexpected death in epilepsy. Overall, about 1 in every 1,000 people with epilepsy dies from SUDEP every year. However, for people with poorly controlled epilepsy, it is about 1 of every 150. Most of these deaths occur during or soon after a seizure.1-4

SUDEP is not the definition used for people with epilepsy who die from injury, drowning, status epilepticus, or other causes tied to a seizure.1

What causes SUDEP?

Doctors do not understand all the reasons why SUDEP happens. This is partly because most sudden deaths happen at night or during sleep. Only about 1 out of 3 of these deaths have a witness.2

Some of the possible causes include:1-3

  • Pauses in breathing – Some people stop breathing during a seizure. If the pause lasts long enough, oxygen levels in the blood can get too low. It is also possible for someone’s airway to get blocked, causing them to suffocate.
  • Changes in heart rhythm – A seizure may cause dangerous changes in how the heart beats, or the heart may stop.
  • Brain function – A seizure may cause vital areas of the brain to stop working, leading to breathing and heart problems.
  • Other causes – A combination of problems during a seizure can cause death.

Who is at risk?

Some people with epilepsy are at higher risk for sudden death, including those ages 20 to 40. This also includes those with:1,3,4

  • Uncontrolled or frequent seizures
  • Generalized tonic-clonic (grand mal) seizures
  • Seizures that happen at night
  • Seizures that begin at a young age
  • Many years living with epilepsy

People with epilepsy who do not take their anti-seizure medicines as prescribed and those who drink alcohol are also at higher risk. Doctors believe people who have only absence or myoclonic seizures have a much lower risk of sudden death.1-3

Among the many things, doctors do not understand about epilepsy is whether genetics play a role in SUDEP.3

Reducing the risk of SUDEP

Because the causes of SUDEP are unknown, the best way to prevent it is to have as few seizures as possible. The best ways to control seizures include:2,3

  • Taking your anti-seizure drugs regularly, as prescribed
  • Avoiding your seizure triggers
  • Getting enough sleep and exercise
  • Avoiding drinking too much alcohol or taking recreational drugs
  • Minimizing stress when possible

It is also important that adults who live with people who have epilepsy know seizure first aid.

Some people have hard-to-control seizures. If your anti-seizure drugs are not controlling your seizures, see a neurologist. Some neurologists even specialize in treating epilepsy. People with hard-to-control seizures may need epilepsy surgery, supportive devices, and changes in diet.2

Keeping a seizure journal can help you better understand your triggers. Avoiding seizure triggers can play an important role in keeping seizures under control.

Some people try anti-suffocation pillows, sleep monitoring devices, and seizure alerts to protect themselves or their loved ones. Talk with your neurologist about whether these devices may provide extra protection.3

Talk to your doctor

Your doctor can help you understand your risk of sudden death if you have epilepsy. Some questions to ask include:3,4

  • What is my risk for SUDEP?
  • How can I lower my risk?
  • How can I prevent future seizures?
  • Are there any other treatments that can reduce my seizures?
  • What should I do if I have another seizure?
  • Will sharing a bedroom help lower my risk?

More research is needed to better understand SUDEP and why it happens.

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