There have been a lot of changes in seizure terminology over time.
Many veterans of the emergency medical services field were not provided the correct information at the beginning of their career. Let’s go through the correct seizure terminology to use in the field.
A seizure occurs when a significant number of brain cells are activated abnormally at the same time, commonly because of a malfunction in the ion channels at the synaptic level, according to Dimitri P. Agamanolis, MD. Commonly refered to as an “electrical storm,” the severity of the seizure depends upon the number of synapses involved.
A seizure also can originate in one or both hemispheres of the brain and can depend on numerous factors, including:
- Even a person’s wake-sleep cycle
Seizure classification and terminology changes
For decades, professionals referred to seizures to as either grand mal or petit mal. While in EMT training in 1993, I learned these terms. But in 1981, a more thorough classification system had already been established classifying the seizure as either a generalized or partial onset, according to the Epilepsy Foundation of Greater Chicago.
Researchers further subdivided these classifications into either a simple or complex partial seizures. There were some drawbacks to this classification system, such as not including some types of seizures. Also, it proved impossible to classify a seizure if no one knew about or witnessed the onset.
Individuals suffering from simple partial seizures stated there is nothing “simple” about it and, quite frankly, the terminology caused confusion.
In 2017, seizures began to be classified by three categories rather than two — generalized, focal onset and unknown onset.
Generalized seizure: This type of seizure is not characterized by the patient’s level of consciousness. This is because the patient will almost always present with an altered mental status.
Focal onset seizures: This type of seizure replaced the confusing partial seizure terminology and is further subdivided into focal onset and focal impaired, formerly known as simple partial and complex partial, respectively.
Unknown onset seizures: There was the addition of an entirely new category of seizures, called unknown onset.
Neurologists use either the generalized or focal classification when they are at least 80% confident about the type of onset. In instances when the clinician feels less than 80% confident, they use the unknown onset category. The unknown onset category is commonly used when the patient experiences an unwitnessed primary seizure and the physical causes have been ruled out, such as a tumor, metabolic or fever. Unknown onset seizures are usually reclassified as either generalized or focal as more information becomes available.
Additional seizure terminology changes you must know
Psychogenic non-epileptic seizures replaced this term in order to better describe the event. First of all, the prefix pseudo- implies the patient is faking the event, which is not accurate.
The patient is suffering from some type of mental stressor. This, combined with the fact they have poorly developed coping mechanisms, causes the the tonic-clonic like activity to manifest.
The patient also can present with less-common presentations, such as absence and focal onset impaired. Non-epileptic has been added to the name because there are no abnormal discharges occurring within the brain.
Psychogenic non-epileptic seizures are hard for even neurologists to diagnose. It can take up to 30 days to diagnose if the patient does not respond to epilepsy medications and no electroencephalogram (EEG) changes occur.
While it is not important for EMS professionals to determine if this type of event is occurring, there are a couple of things you can look for that can help the neurologist make the diagnosis later.
The patient will have a hypertonic phase that lasts an abnormally long time and the event always will occur in the presence of a witness.
Historically defined as an event that lasted longer than 30 minutes. The patient may present with a continuous seizure or multiple seizures without a period of lucidity. This means the patient has become unalert or disoriented, and cannot interact with you or bystanders.
These seizures are concerning because the patient may not be breathing. Even if they are breathing, it will not be in a manner that meets demands being placed on the body.
Because of this, the new timeframe being used to determine a patient is in status is 5 minutes because most seizures last between 30 seconds and 2 minutes.
Something to keep in mind when responding to a seizure is the national average from time of onset of an emergency to EMS arrival is between 10 and 12 minutes.
If the patient is seizing upon your arrival, he or she should be treated as though they are status epilepticus until proven otherwise.
EMS seizure education tip
A new development notes it’s not important for prehospital providers to determine the exact type of seizure that has occurred. There are 24 types of seizures that can occur, most of which we do not discuss during initial education, according to the Epilepsy Foundation of Greater Chicago.
It is more important that when we respond to a seizure to first determine if the patient is in status epilepticus.
If that is not a concern, the most important information you can obtain in regard to presentation is a change in the patient’s mental status and what types of movement with which the patient presented.
You may not be able to determine the category or type of seizure that is occurring, but the neurologist can use the information provided by you and witnesses to determine the type.
For information about seizures join me in our 48-hour paramedic refresher course, which includes:
- Lesson 9 on diabetes, seizures and infectious disease
- Lesson 19 which includes pediatric seizures