Epilepsy: Everything you need to know!
Published Feb 14, 2022 • By Candice Salomé
The word "epilepsy" comes from the Greek word "epilambanein" which means "to attack by surprise". Epilepsy is a chronic disease characterized by epileptic seizures. These seizures are the result of a sudden and transient disturbance in the electrical activity of the brain.
Around 1.2% of the total US population has active epilepsy. This amounts to almost 3 million adults and 470,000 children.
So what is epilepsy? How do its seizures manifest themselves? What causes them? How can epilepsy be treated?
We explain it all in our article!
What is epilepsy?
Epilepsy is a chronic disease characterized by a sudden increase in the electrical activity of the brain. This leads to a temporary disruption of communication between neurons. Epilepsy manifests itself by seizures resulting from a 'hyperexcitation' of the nerve cells, or the neurons, in the cerebral cortex.
There are four types of epilepsy, which include different types of seizures causing different symptoms and having different onsets. These include:
- Focal epilepsy: This type involves focal (or partial) seizures, which begin on one side of the brain. About 60% of all types of epilepsy are focal.
- Generalized epilepsy: This type involves generalized-onset seizures, meaning they begin on both sides of the brain and cause impaired or loss of consciousness. Around 23-35% of epilepsy cases are generalized.
- Combined generalized and focal epilepsy: If both focal and generalized seizures occur, it is known as generalized and focal epilepsy.
- Unknown-onset epilepsy: When the type of seizure is not known (if the seizure occurs during the night, if there is not enough medical information to classify the seizure), the epilepsy will be categorized as "unknown" until more information can be gathered.
Some seizures, sometimes referred to as "circumstantial" seizures, may remain unique. They may be linked to a triggering factor that temporarily irritates the brain (acute infection, alcohol, hypoglycemia, etc.). In this case, it is referred to as a non-epileptic seizure, and not as epilepsy.
There are also epilepsy syndromes, which refer to a set of medical features that typically occur together. Epilepsy syndromes are different from epilepsy types, which only indicate the type of seizure; the classification of epilepsy syndromes includes seizure type, age when the seizures typically begin, EEG results, genetic factors, common triggers, outlook, response to drug treatment, and other symptoms. There are more than 30 known epilepsy syndromes, such as gelastic epilepsy, childhood absence epilepsy, Dravet syndrome, Lennox-Gastaut syndrome, Laundau Kleffner syndrome, and West syndrome, among others.
What are the symptoms of epilepsy?
An epileptic seizure is a transient clinical manifestation of abnormal electrical activity in the nerve cells of the cerebral cortex. There is no single definition of an epileptic seizure. There are several types of generalized seizures:
- Tonic-clonic seizures (previously called grand mal seizures), which are the most familiar to the general public due to their visible and severe symptoms. These may include crying out, collapsing, loss of consciousness, muscle stiffening (tonic phase), jerking (clonic phase), drooling, apnea, etc. The patient typically loses consciousness and has no memory of the seizure afterwards.
- Clonic seizures are characterized by muscle spasms and jerking for several minutes. The patient may lose awareness.
- Myoclonic seizures, which are brief muscle twitches that can occur in full consciousness.
- Absence seizures (formerly called petit mal seizures), which are brief lapses of consciousness, sometimes associated with abnormal movements of the eyelids (clonus). These seizures occur mostly in children and may happen several times a day or even hourly. The patient may lose awareness and responsiveness while appearing to still be conscious.
- Tonic seizures, which causes muscle stiffening without a clonic phase. Patients may experience a brief change in their awareness or may stay conscious.
- Atonic seizures, also called drop attacks, are characterized by a sudden loss of muscle tone, which may then cause brief loss of consciousness, followed by a collapse, and sometimes unintentional passing of urine. This is the rarest type of seizure and usually lasts only a few seconds. The person can then resume his or her normal activities.
There are also several types of focal (partial) seizures:
- Simple focal seizures: These can be similar to and often occur with seizure auras. Patients tend to stay conscious and aware, but partially unable to respond. They may cause anxiety, hallucinations, a felling of déjà vu, muscle jerking, and strange sensations, such as strange smells. These may progress into complex focal seizures.
- Complex focal seizures: These cause altered consciousness, but not necessarily full loss of consciousness. Patients may also experience blank staring, confusion, and repetitive movements like blinking or swallowing.
- Secondarily generalized seizure: When a simple or complex focal seizure progresses to a generalized seizure, it is referred to as a secondarily generalized seizure.
What causes epilepsy?
Epilepsy is a multifactorial disease. However, sometimes no cause can be found, in this case the condition is known as unknown-onset epilepsy. Various factors are involved in the development of epilepsy:
- Genetics: Genetics plays a role in two thirds of all epilepsy cases. Apart from some forms passed down through families and caused by a single gene abnormality, epilepsy is most often related to abnormalities present in several genes.
- Lesions in the brain: These can be caused by tumors, stroke, cerebral hematoma, etc.
- An infectious disease of the nervous system: Meningitis, encephalitis, etc.
- Head trauma
- Cerebral malformation: This may include conditions such as tuberous sclerosis, a hereditary disease affecting the skin and nervous system.
- Systemic disease: Including conditions such as systemic lupus erythematosus (SLE)
- Chronic alcoholism
- Abnormality in the development of certain areas of the cerebral cortex.
Unfortunately, in about 60% of cases, doctors are not able to determine the exact cause of the seizures.
How is epilepsy diagnosed?
The diagnosis of epilepsy is based on the recurrence of the seizures, their nature and a series of additional tests that help understand their origins.
The diagnosis also defines the type of epilepsy (focal, generalized, or other) that the patient has. The diagnosis is therefore based on:
- A patient and family interview: To understand the circumstances of the seizures, description of the symptoms, their duration and frequency, medical history, etc.
- A clinical examination of the patient and a search for possible triggering factors,
- An electroencephalogram (EEG): This examination provides a trace of the electrical activity of the patient's brain. In the case of epilepsy, specific abnormalities can be detected between seizures, which are either permanent or intermittent. They are known as spikes, or spike waves, in certain areas of the brain.
In order to determine the cause of epilepsy, doctors use medical imaging techniques such as CT or MRI, which allow the structures of the brain to be visualized.
These examinations are not, however, systematic. Other tests and exams such as blood tests or the examination of the back of the eye can be useful in determining the cause.
How is epilepsy treated?
It is not necessary to see a specialist for every epileptic seizure. However, it may become necessary if:
- It is your first seizure,
- You notice any changes in the way you feel during and after a seizure,
- You notice any signs of injury related to a seizure,
- The frequency of your seizures varies.
An anticonvulsant (or antiepileptic) drug will stop seizures in the vast majority of patients. For others, it can at least reduce the number of seizures and their intensity.
Generally, the use of a single drug is sufficient. However, it is often necessary to test several medications before finding the one that suits the patient best.
The drugs that have been used for many years to treat epilepsy are phenytoin (Dilantin®, Phenytek®), carbamazepine (Tegretol®, Carbatrol®, Epitol®, Equetro®) and valproic acid.
Others are more recent: gabapentin (Neurontin®), lamotrigine (Lamictal®), topiramate (Topamax®, Qudexy XR®, Trokendi XR®), and levetiracetam (Keppra®, Elepsia XR®, Spritam®). Pregabalin (Lyrica®) is an analogue of gabapentin, which causes slightly fewer side effects.
Some treatments, such as phenytoin or carbamazepine can increase the elimination of vitamin D, which in the long term can cause osteoporosis. Your doctor may prescribe a vitamin D-calcium supplement, in order to avoid this.
Epilepsy Data and Statistics, Centers for Disease Control and Prevention
Épilepsie : définition, causes, facteurs favorisants, Ameli
Are There Different Types of Epilepsy?, Healthline
Qu’est-ce que l’épilepsie ?, Fédération Française de Neurologie
L’épilepsie : causes, mécanismes biologiques, symptômes, diagnostic et traitements, Institut du Cerveau