Seizures and Epilepsy
A seizure is a sudden episode of abnormal brain function caused by a surge of abnormal brain electrical activity …
Epilepsy is a disorder in which an individual has a tendency to get unprovoked seizures .
Most individuals with epilepsy are able to live normal and fulfilling lives, both socially and professionally
A seizure is a sudden episode of altered brain function where a large number of neurons discharge in unison, rhythmically, for an extended period of time–at least several seconds, sometimes many minutes. Normally, only small groups of neurons discharge in unison, and only for a short period of time –milliseconds. On the other hand, …
A seizure is also–from the point of view of an individual experiencing a seizure–a sudden stiffening or jerking of parts of the body; and or a sudden change in awareness or sensation or clarity of thought or emotion.
The second definition may see much more useful to an individual who has a seizure. They might reasonably say: “I can know if my body jerks or if my sensation or awareness changes. How can I know if neurons are discharging abnormally in my brain?” This is exactly right–except for…
Sometimes, a “seizure” can occur within an individual’s brain without that individual noticing. That individual may have very vague symptoms that come and go: Daydreaming, confusion, forgetfulness. A neurologist can investigate brain function and find out that that individual has frequent little seizures that they don’t notice directly. How can a neurologist investigate brain function you ask…
EEG (electroencephalography) is a procedure that measures of electricity coming from brain and can identify electrical signs of seizure–large numbers of neurons discharging rhythmically in unison. A neurologist can order an EEG if they suspect seizures are occurring.
EEG can be helpful in other situations: Sometimes, an individual may have an episode of sudden stiffening or jerking, or sudden change in awareness or clarity, without having a “seizure.” For instance, jerking of an arm or leg can occur because of damage to nerves outside the brain and then would not be a seizure. Such a condition is treated quite differently from seizure. EEG can be useful in this situation as well.
You may ask: Can an EEG “after the fact” tell a neurologist whether an event in the past was a seizure? How can EEG when a person is not having a seizure tell the neurologist about a seizure in the past? The short answer is yes, and EEG “after the fact” can (sometimes) tell a neurologist whether a previous event was (most likely) a seizure. The details are a little complicated–we will go into this with the future website update.
Epilepsy is thought of by medical scientists very simply as a predisposition to have repeated seizures. This is succinct but not helpful–it does not tell us how to diagnose an individual who has had a seizure–or several seizures–with epilepsy. More pragmatically…
Epilepsy is diagnosed when an individual has 2 or more “unprovoked” seizures. In addition, epilepsy is also diagnosed after only one seizure by an individual who has “risk factors” for repeat seizures. (This is the working definition set as standard by the International League Against Epilepsy.)
This definition of epilepsy is much more useful–and is backed up by data. After 2 unprovoked seizures, about 60-65% of people have subsequent seizure within the next 2 years. With only one unprovoked seizure, the risk is only 21-45%. If an individual hasn’t had a subsequent seizure after a few years (2-5 years by various estimates), the risk of seizure recurrence becomes relatively low. These data allow neurologists to decide when to offer anti-seizure medication. Repeat seizures can be scary and can be dangerous. Antiseizure medications can prevent repeat seizures, without significant side effects, in two thirds or more of individuals who have epilepsy by the above definition. On the other hand, many individuals (and neurologists) do not like to employ a medication unless it is truly necessary. Standard of care by the American Association of neurology is to offer antiseizure medication when epilepsy is diagnosed by the above definition.
The definition of epilepsy can occasionally still be frustrating. There are gray areas: What does “unprovoked” mean? What are sufficient “risk factors?” What if an event is not clearly a “seizure?”
Unfortunately, there is no easy way around these frustrating gray areas. The human brain is complex. However, we have to make decisions and we do have practical definitions of these terms (backed by some data) that allow us to get past some of these uncertainties:
“Provoking situations” for seizure
“Unprovoked” means that a seizure has occurred in the absence of recent “provoking situations,” which include:
- Drugs (medicines): The vast majority of prescription medications do not have significant risk of provoking seizure. Yet, there is a long list of prescription medications that have been associated, at least anecdotally with seizure risk. Most of these, still, have very small risk and can be safely used without concern for seizure in individuals without a diagnosis of epilepsy. Wellbutrin and tramadol are the 2 medications that are noticed most prominently in emergency rooms as provoking agents of seizures.
- Drugs (“recreational”): Alcohol, cocaine and amphetamines are the most likely recreational drugs to cause seizure. (People often ask about marijuana. Marijuana is associated with some case control data that it actually REDUCES seizure risk, possibly via the action of cannabidiol (CBD) . Click here to read the American Epilepsy Society position on medical marijuana for epilepsy.)
- Brain insult: “Insult” is an “English term turned medical,” here meaning “something recently gone wrong” with the brain. There are many “insults” that, if severe enough, can provoke seizure during or soon after the insult. These include brain trauma, stroke, brain bleed, brain infection, brain tumor. “Soon” is not precisely defined, but some have suggested “within one week.”
- Systemic disorder: Another umbrella term, where “systemic,” to neurologists, means (somewhat parochially), any part of the body that is NOT part of the nervous system. Again, the list is long but notably includes extremely high blood pressure; extremely high or low blood sugar; extremely low sodium, calcium or magnesium; extremely high body temperature; or brain deprivation of oxygen (e.g., from cardiac arrest).
“Risk factors” (for repeat unprovoked seizure):
- “Appropriately” abnormal EEG (click here for EEG details);
- Family history of epilepsy; certain congenital conditions involving brain abnormality (e.g. tuberous sclerosis);
- Remote brain insult.
The last category bears additional explanation as it might seem paradoxical: brain insult is listed above among provoking situations for seizure–so brain insult seems like it shouldn’t count toward diagnosis of epilepsy; yet here brain insult is listed as a risk factor so it DOES count toward diagnosis of epilepsy. But note…
The key word is “remote,” as in “a while ago.” If a seizure occurs more than a week after a brain insult, then data reflect that this seizure is not provoked by the insult itself; this seizure is caused by some permanent change in the brain in reaction to the insult that has rendered the brain more likely to have a seizure. (Hesdorffer et al. Epilepsia 2009, Beghi et al. Epilepsia 2010;51:671-675; in Fisher et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia, 2014; 55:475-82)
How about the term “seizure disorder”–where does that fit in?
This one is easy: “Epilepsy” and “seizure disorder” are identical–they are alternative terms for the same exact thing.
The stigma of epilepsy
Many individuals prefer the term “seizure disorder” as “epilepsy” carries stigma in some people’s minds. There is no doubt that a seizure can be scary, certainly for an individual who has a seizure, but also for people who witnessed a seizure. Nevertheless, there is a stigma and some circumstances that can serve as an on necessarily restricted barrier for an individual with epilepsy, both at home and at work place. The fact is that most individuals with epilepsy are able to leave normal and fulfilling lives, both socially and professionally. The Epilepsy Foundation website, epilepsy.com, is a wonderful source for understanding seizures and epilepsy, both for an individual with epilepsy, and for their relatives, friends and coworkers.