Definition

Traditional definition of SE

Traditional definitions of SE refer to either:

• A single seizure persisting for more than 30 minutes

• Multiple seizures of shorter duration without a full neurological recovery in between seizures

Revised definition for SE?

There is a growing body of support for the definition of SE to refer to seizures that persist for more than five minutes without intervention [1-6].

This relates to evidence demonstrating that:

• A significant proportion of seizures that continue for five minutes will persist for longer than 30 minutes

• The average seizure duration in adults is less than one minute

Hence, seizures that persist beyond five minutes represent a significant deviation from the norm.

Further to this, there is evidence that neuronal injury can result after just five minutes of seizure activity.

Impending SE

More recently, the use of the term 'impending status epilepticus' has been advocated to describe continuous or intermittent seizures that persist beyond five minutes without neurological recovery [6].

This definition recognises the immediate requirement for treatment for such patients, but acknowledges that not all are in established SE, and that up to 40% of these may terminate spontaneously within 30 minutes.

Established SE refers to clinical or electrographic seizures that persist for 30 minutes or longer without full neurological recovery in between.

Refractory SE is defined as the persistence of convulsions despite adequate doses of two intravenous anticonvulsant agents.

SE may be subdivided into convulsive and non-convulsive forms. These will be discussed in greater detail.