Autonomic seizures are characterized by symptoms primarily affecting your autonomic nervous system. Your autonomic nervous system controls functions out of your conscious control, such as heart rate and blood pressure regulation.

Seizures are uncontrolled bursts of electrical activity in your brain that cause symptoms like:

  • loss of consciousness
  • rapid eye movements
  • loss of bowel or bladder control
  • muscle stiffening or twitching

Read on to learn more about autonomic seizures, including their symptoms, causes, and treatment options.

Your autonomic nervous system controls functions like regulating your:

  • heart and breathing rate
  • digestion
  • sexual arousal
  • blood pressure

Seizures can affect any of your autonomic functions, but cardiovascular changes seem to be most common.

Potential symptoms of autonomic seizures include:

Autonomic seizure symptoms in children

A type of epilepsy syndrome called “self-limited epilepsy with autonomic seizures” accounts for about 5% of childhood epilepsies between the ages of 1 and 14 years. Epilepsy is defined as recurring seizures without a known cause.

About one-third of people with this type of epilepsy only have one seizure, and only 5% have more than 10 seizures.

This type of seizure can cause many different symptoms, such as:

  • repeated vomiting
  • nausea
  • paleness
  • status epilepticus, which is a seizure that lasts for longer than 5 minutes or multiple seizures occurring close together

The cause of autonomic seizures is often unknown. Potential risk factors include:

Autonomic seizure classification

The International League Against Epilepsy updated its classifications of seizures in 2017. Under its classification system, seizures can either be focal onset, if they begin on one side of the brain, or generalized onset, if they begin on both sides of the brain.

Focal onset seizures are subclassified as either motor onset, if they begin with movement symptoms. or non-motor onset, if they begin with non-movement symptoms.

Non-motor focal onset seizures can be further broken down into:

  • autonomic
  • behavioral
  • cognitive
  • emotional
  • sensory

What triggers an autonomic seizure?

For people with epilepsy, common triggers of focal onset seizures include:

Seizures can cause complications that include:

  • injury from falls
  • breathing in food or saliva, which can lead to aspiration pneumonia
  • learning problems, if seizures are frequent
  • side effects from antiseizure medications

Sudden unexpected death in epilepsy

Sudden unexpected death in epilepsy (SUDEP) is a sudden death in somebody with epilepsy not caused by an injury, drowning, or any other known cause. According to the Centers for Disease Control and Prevention (CDC), it occurs in about 1.16 per 1,000 people with epilepsy per year.

The exact cause of SUDEP isn’t known, but there’s relatively strong evidence to suggest that it’s linked to:

  • cardiac dysfunction
  • pulmonary dysfunction
  • brainstem stimulation
  • neurotransmitter dysregulation

Some focal seizures cause a loss of consciousness. Focal onset non-motor seizures generally last for less than 2 minutes.

You can have many different sensations during your seizure, such as:

  • suddenly feeling sick
  • unpleasant sensations in your chest or head
  • changes in your heart rate or breathing
  • sudden sweating or goosebumps

Some people feel fine immediately after their seizure, while others have symptoms like confusion or tiredness. These symptoms may only last for a few minutes, or they could linger for hours or days.

If you’re with somebody having a seizure, you can help them by:

  • speaking calmly
  • keeping other people calm
  • offering to help them get home
  • checking to see if they have a medical bracelet
  • staying with them until the seizure is finished

It’s important to visit a doctor if you develop a new type of seizure or if you develop new symptoms.

Medical emergency

Call emergency medical services or go to the nearest emergency room if you or someone you’re with:

  • has a seizure lasting for longer than 5 minutes
  • experiences a first seizure
  • has trouble breathing or walking after a seizure
  • has a second seizure shortly after the first
  • has a seizure in water
  • is living with a health condition like diabetes or heart disease
  • is pregnant

Autonomic seizures are rare, and doctors will often first rule out conditions with similar symptoms, such as heart disease or hormone dysfunction.

Doctors use a variety of tests to diagnose the underlying cause of seizures, such as:

  • a review of your personal and family medical history
  • a review of your symptoms
  • routine electroencephalogram (EEG)
  • prolonged EEGs, such as video EEGs, where you wear an EEG machine and camera over several days
  • brain imaging, such as:
  • a neurological exam

Do autonomic seizures show up on EEG?

EEG is one of the most important tests for diagnosing epilepsy. If you have an autonomic seizure during the test, your doctor may see atypical brain activity.

Doctors primarily treat recurring autonomic seizures with antiseizure medications. You may need to try different combinations of medications before you find one that works.

About 1 in 10 people have a seizure in their lifetime. The outlook for seizures varies widely depending on the underlying cause.

Some people who have seizures in childhood outgrow them, while other people may need to take medications for the rest of their lives.

Autonomic seizures are primarily characterized by brief autonomic nervous system symptoms. They can cause many different symptoms, like sudden nausea or changes to your heart rate.

It’s important to contact a doctor if you have your first seizure or develop new symptoms. They can help identify the underlying cause and prescribe medications to treat your seizures.