Epilepsy and Seizures, What’s the difference?

seziure

What is a Seizure?

A seizure (or “fit”) is physical finding or change in behavior that occurs because of abnormal electrical activity in the brain.

When people think of a seizure, they usually imagine a generalized (or “Grand Mal”) tonic clonic seizure:

It is estimated that as many as 5% of all Americans will experience an epileptic seizure during their lifetime.
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What is epilepsy?

Epilepsy results from a permanent change in brain tissue causing it to be too excitable, leading to repeated unpredictable seizures over time.

This can occur from a brain injury, such as head trauma, birth asphyxia or a stroke, brain tumor or can be genetic (something you were born with).

The prevalence of epilepsy is estimated to be 1-2% in the USA.

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Not all seizures lead to epilepsy.

Why is the prevalence of epilepsy so much lower than the incidence of seizures?

The answer is that not all seizures will lead to epilepsy.

A seizure can be provoked by some extraneous factor such as high fever, medication, drugs and alcohol, or blood electrolyte disorder, which if addressed properly will not lead to further seizures.

However, a single seizure can also be the beginning of epilepsy, necessitating an anti-epileptic medication (or anticonvulsant) to prevent further episodes.

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So, how do you tell if a first seizure is the beginnings of epilepsy?

All patients presenting with their first seizure should have a thorough evaluation, including a detailed history (from someone who observed the episode), physical examination, blood work, brain imaging study and electroencephalogram.

A seizure which begins with a focal onset, such as a warning (“aura”), unusual behavior (“automatism”), or focal movements just as turning the head to one side or jerking on one side of the body suggests the beginnings of epilepsy from an underlying brain injury or lesion.

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Seizure with automatism (Partial Complex Seizure):

Note that the patient appears awake, but is not responding normally, and has lip smacking and pointing (the automatisms), indicating a focal (temporal lobe) seizure onset.  He seems confused and disoriented afterwards.

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Seizure with focal motor activity:

Although the patient is unresponsive and jerking, note that the head is turned to the right and there are only right sided limb movements, indicating that the seizure is coming from the left side of the brain.

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Some genetic seizure syndromes, like juvenile myoclonic epilepsy or absence epilepsy (“petit mal”) begin in childhood or adolescence, are associated with characteristic EEG findings, and indicate epilepsy which will be recurrent without treatment.

Absence seizure:

The child is talking, then suddenly stops and stares off into space, then suddenly resumes speech as if nothing happens. This is a typical absence seizure or “Petit Mal” from epilepsy and will recur without treatment.

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There are physical signs which suggest an underlying neurocutaneous syndrome, and epilepsy:

Syndrome characterized by a facial port-wine stain, seizures, paralysis or weakness on one side, learning disabilities, and "calcifications" in the brain

Syndrome characterized by a facial port-wine stain, seizures, paralysis or weakness on one side, learning disabilities, and “calcification” in the brain

Genetically determined syndrome of epilepsy associated with     Areas of the skin that are white (due to decreased pigment) and have either an ash leaf or confetti appearance    Red patches on the face containing many blood vessels (adenoma sebaceum)    Raised patches of skin with an orange-peel texture (shagreen spots), often on the back

Genetically determined syndrome of epilepsy associated with: Red patches on the face containing many blood vessels (adenoma sebaceum) . Areas of the skin that are white (due to decreased pigment) and have either an ash leaf or confetti appearance . Raised patches of skin with an orange-peel texture (shagreen spots), often on the back . Small tumor like lesions at the nail folds (subunguual fibromas) .

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Genetically determined epilepsy syndrome associated with fatty tumors, pigmented patches (including in the arm pits), and Lisch nodules in the iris.

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The presence of an abnormal EEG in a patient presenting with a single seizure increases the chances of another seizure (epilepsy) and may warrant initiation of an anticonvulsant medication. This could be either a focal spike suggesting a partial onset seizure focus:
EEG spike
Or a burst of generalized spike wave activity, suggesting a genetic generalized epilepsy:
EEG JME

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A patient with seizures and an abnormal brain imaging study is also more likely to suffer a recurrence and develop epilepsy:
Abnormal Brain MRIs in Epilepsy

However, if all the tests are normal, it can be hard to tell if a single unprovoked seizure is the beginning of epilepsy or not, only about 20-30% of these patients will have a recurrent event, so sometimes it is better to wait and see what is going to happen rather than rushing into starting an anticonvulsant medication here.

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Where to get more help.

These are complicated issues and decisions which should only be made after consultation with a neurologist, preferably a neurologist with subspeciality training or certification in epilepsy at an epilepsy center.

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