2017 Revised Classification of Seizures

The International League against Epilepsy (ILAE) is the world's main scientific body devoted to the study of epilepsy, and it has recently revised its classification of seizures. The changes will help make diagnosing and classifying seizures more accurate and easier. In this article, you'll find the new general outline and basic seizure classification. In the coming weeks, epilepsy.com will be updated to reflect the new classification to help users searching for both the older and newer terms.

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  • Refractory (uncontrolled) epilepsy is a heavy burden.
  • First it's important to make sure that the diagnosis of epilepsy is correct and that the proper medicines are being used in the best way for each person.
  • The individual with epilepsy needs to look at things they can do to better control their seizures, such as remembering medicines, staying in good health, getting good sleep, minimizing stress and avoiding seizure-precipitating conditions.
  • Non-drug therapies, such as epilepsy surgery, vagus nerve stimulation, responsive neurostimulation, dietary therapies, or experimental clinical trials, may be good options for some people.
  • Only 5% of people (1 out of 20) with refractory epilepsy get better each year. The biggest hope is for new therapies to prevent and cure epilepsy!

What does uncontrolled or refractory seizures mean?

Seizures sometimes are not controlled with seizure medications. A number of different terms may be used to describe these including: “uncontrolled,” “intractable,” “refractory,” or “drug resistant.” How often does this happen?

  • Studies suggest that epilepsy fails to come quickly under control with medicines in about one-third of cases, but the true frequency depends upon the definition of uncontrolled.
  • Most epilepsy specialists agree that refractory epilepsy is epilepsy for which seizures are frequent and severe enough, or the required therapy for them troublesome enough, to seriously interfere with quality of life.
  • However, in more recent years, the epilepsy community has recognized the need to continue striving for ‘no seizures’ and the best control possible.
  • The International League Against Epilepsy (ILAE) has proposed the following definition of drug resistant epilepsy and suggests that this term be used instead of the term 'refractory epilepsy'.
    • Drug resistant epilepsy occurs when a person has failed to become (and stay) seizure free with adequate trials of two seizure medications (called AEDs).
    • These seizure medications must have been chosen appropriately for the person’s seizure type, tolerated by the person, and tried alone or together with other seizure medications.

What are the reasons for uncontrolled seizures? 

Seizures can be uncontrolled for four broad reasons.

  • The diagnosis is wrong.
  • The treatment is wrong.
  • Despite the best treatment, triggers or lifestyle factors may affect seizure control.
  • Properly diagnosed seizures do not respond to the best medical treatment.

Not all uncontrolled seizures are considered refractory or drug resistant. For example:

  • If the diagnosis is corrected and seizures can be brought under control with a different treatment, then they would not be considered refractory.
  • If triggers of lifestyle factors could be avoided or modified preventing breakthrough seizures, then medication therapy may work better. A person in this situation would not be considered drug resistant, but different drug trials may be considered and non-drug treatments may be considered to help control seizures.

If the diagnosis is wrong, what’s causing the seizures?

Imagine coming home at night after too much partying, and finding yourself unable to unlock your front door. One possibility is that you are at the wrong house.  Another is that you are using the wrong key. Or you really may be locked out. Perhaps someone inside has engaged the deadbolt. Refractory epilepsy displays three similar categories.

An incorrect diagnosis of epilepsy, going to the wrong house, is more common than most people might think. One chart review study by Smith and colleagues in England found that 13% of patients referred for refractory epilepsy did not have epilepsy. If seizures are not controlled, then a reasonable first question is: “Are the episodes really seizures?” A number of conditions can imitate seizures.

Authored by: Robert S. Fisher, MD, PhD | Patricia O. Shafer RN, MN | Joseph I. Sirven, MD on 11/2013
Reviewed by: Patricia O. Shafer, RN, MN | Joseph I. Sirven, MD on 1/2014

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