A breakthrough seizure occurs when a person has a seizure after controlling their condition with medication for at least 12 months. They are sometimes known as recurrent seizures.

Epilepsy is a neurological condition that causes seizures. The Centers for Disease Control and Prevention (CDC) state that, as of 2015, about 3.4 million people in the United States were living with epilepsy.

A 2017 article notes that 60–70% of people with epilepsy achieve remission from seizures when they use antiseizure medications properly. However, 37% will have a breakthrough seizure, which is a seizure after a minimum of 12 months of being seizure-free while taking medication.

This article explains the causes, symptoms, diagnosis, treatment, and prevention of breakthrough seizures.

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There are many types of seizures, and a person with epilepsy can experience more than one type. A breakthrough seizure can be one of the following types of seizures: Generalized or focal onset.

Generalized seizures affect both sides of the brain. They include absence seizures and tonic-clonic seizures.

Focal onset seizures affect one area of the brain. They include focal aware seizures, focal impaired awareness seizures, and focal to bilateral tonic-clonic seizures.

Both types of seizures may affect a person’s awareness, thinking, and senses. They can also cause physical symptoms, such as muscle stiffening or relaxing, twitching, and lip-smacking.

There are many reasons a breakthrough seizure can occur after the condition is well-controlled. They include:

  • an individual’s medication dose is no longer sufficient to prevent a seizure
  • missed doses of medication
  • stress
  • sleep deprivation
  • alcohol use or alcohol withdrawal
  • exposure to TV or video games with flicker or rapid flashes of alternating colors

Other factors may increase a person’s risk of having a breakthrough seizure. They include:

  • infection
  • low blood sugar resulting from fasting
  • caffeine
  • medications such as hormone replacement, antibiotics, or painkillers

The doctor will take a detailed medical history to diagnose a breakthrough seizure, including information about the episode. They will ask about the duration and symptoms, recent illnesses, and warning signs that the seizure was beginning.

Many people who experience a seizure lose consciousness or awareness during the episode. For this reason, the doctor may want to speak with anyone nearby during the seizure to gather more information.

The doctor may also order brain imaging to look for any physical abnormalities, such as a tumor or injury, and unusual electrical patterns. Imaging tests may include:

  • computed tomography (CT) scan
  • magnetic resonance imaging (MRI) scan
  • electroencephalogram (EEG)

Treatment for a breakthrough seizure may involve adjusting medications or avoiding triggers. If doctors cannot determine the cause of the breakthrough seizure, it may be more difficult to prevent further episodes. If there is no obvious cause, doctors may suggest increasing a person’s medication dosage.

However, the 2017 study found that people who increased their medication dosage following a breakthrough seizure were at higher risk of more episodes. This may be because lifestyle factors are responsible for triggering seizures rather than not taking antiseizure medication properly.

A 2019 study looked at remission following a breakthrough seizure. Of the participants who experienced remission following a breakthrough seizure:

  • 66% did not change their treatment
  • 32% increased their antiseizure medication dose
  • 2% lowered their dose

Among participants who did not experience remission:

  • 52% made no changes to their medication dose
  • 45% raised their dosage
  • 3% lowered their dosage

To prevent breakthrough seizures, people must keep up with the treatment schedule their doctor recommends. Missed medication is a common reason for breakthrough seizures.

People can try the following tips to help them remember to take their medications:

  • Take medication alongside a regular daily activity such as brushing teeth or eating a meal.
  • Set an alarm.
  • Use a pillbox.
  • Keep medication visible.
  • Put a reminder note somewhere visible.
  • Flip the pill bottle over after taking the dose.
  • Record each dose in a calendar or journal.
  • Ask caregivers to help.
  • Use a mobile medication reminder app.

People can also try to avoid common seizure triggers, such as sleep deprivation, stress, and drinking alcohol.

Many people with epilepsy can be seizure-free when they take medication as a doctor prescribes. However, some people will experience repeated breakthrough seizures.

A 2017 study of 510 people with epilepsy examined the following factors:

  • the risk of a breakthrough seizure
  • how likely a person is to achieve remission following a breakthrough seizure
  • the likelihood of being seizure-free for 12 months following a breakthrough seizure

The study found that:

  • at 2 years following remission, the risk of a breakthrough seizure was 37%
  • at 2 years following a breakthrough seizure, the chance of achieving a 12-month remission period was 64%
  • after the first breakthrough seizure, the risk of more episodes in the following 2 years was 74%

Breakthrough seizures occur after a person has been seizure-free with treatment for at least 12 months. They can be any subtype of generalized or focal seizure.

The most common cause of a breakthrough seizure is noncompliance with medications. Other causes of breakthrough seizures include sleep deprivation, stress, drinking too much alcohol, or taking recreational drugs.

Doctors may order imaging scans to examine the brain for unusual electrical activity or physical abnormalities that can cause a breakthrough seizure. They may also recommend adjusting a person’s medication regimen.

People can help prevent breakthrough seizures by taking medications as a doctor prescribes and avoiding known triggers.