Epilepsy

"The history of epilepsy can be summarized as 4,000 years of ignorance, superstition, and stigmatization, followed by 100 years of knowledge, superstition, and stigmatization" Rajendra Kale, 1997 ^[190].

General Overview :

The term epilepsy is derived from Greek; it means "to be seized" or "taken by surprise" ^[186].

Epilepsy ^{[41, 69, 179, 185]} is a neurological condition characterized by recurrent seizures that involve:

Clinically: Tonic-clonic motor manifestations, sensory and autonomic disturbances, and/or an alteration of consciousness.

Electroencephalography: A characteristic tracing of paroxysmal electrical activity ^[187].

Epilepsy is the most frequent chronic neurological condition after migraine ^[187]. It is a relatively benign pathology in most cases, but its psychological, familial, and social impacts are often far greater than the severity of the disease itself.

It should be noted that epilepsy is not a mental illness ^[69], contrary to popular belief, even though it may be accompanied in some cases by certain behavioral and cognitive disorders.

Pathophysiology :

An epileptic seizure is the clinical consequence of excessive, hypersynchronous, and self-sustaining paroxysmal discharges from a more or less extensive population of cerebral neurons ^[75].

This synchronized discharge results from an imbalance between inhibitory and excitatory mechanisms ^[188], leading to intense and disordered neuronal activity. This activity, which sometimes originates from a small cortical area (epileptogenic zone) ^[187], spreads gradually through the cerebral cortex.

Seizures manifest in very diverse ways, depending on the area of the brain where the discharge begins and its mode of propagation. For example, a partial seizure localized in the occipital lobe will result in abnormal visual perception; if it propagates forward, it may lead to motor or sensory phenomena. If it spreads to the entire brain, it may transform into a generalized tonic-clonic seizure ^[31] (grand mal) ^[75].

An epileptic seizure is a highly dynamic phenomenon that abnormally and successively involves various brain structures and, consequently, their functions (language, motor or sensory phenomena, eye movements, etc.).

The initial clinical signs have significant localizing value. Often, an (aura) ^[187] may occur - a phenomenon that is almost always identical for the same person, announcing the imminence of the seizure. Being able to describe it helps to specify the origin of the seizure. Usually, the discharge follows the same pathway, so the signs remain consistent for the same individual.

Classification :

Several types of epileptic seizures can be distinguished. For example, there are convulsive and non-convulsive seizures; they can be partial or generalized; they may or may not involve loss of consciousness; they can be purely motor or sensory, and occur while fully conscious.

According to origin :

• Symptomatic epileptic seizure: Secondary to a well-defined cause (trauma, tumors, etc.) ^[187].
• Essential epilepsy ^[107]: The most widespread form, idiopathic, without a notable organic cause. This refers to the epileptic disease itself.
• Cryptogenic epilepsy: Has an underlying organic cause ^[145] that remains undetected despite investigation ^[187].

According to clinical manifestations :

When seizures originate in a localized area of the brain, they are called partial ^[188]. When they involve the entire brain, they are called generalized ^{[67, 187]}.

Generalized seizures :

• The tonic-clonic seizure (grand mal):

This is the most well-known because it is the most spectacular ^[107]. It manifests as a fall, loss of consciousness, tonic-clonic convulsions, tongue biting, and sometimes loss of bladder or bowel control. It carries a risk of more or less serious injury and usually stops after about a minute.

Status epilepticus ^[69] is a sequence of generalized epileptic seizures without interruption and without a return to consciousness; the coma is deep, and severe autonomic disturbances occur, threatening the patient's life. The status epilepticus is a medical emergency.

• Absence :

Absence ^[188] is a type of generalized seizure involving a brief suspension of consciousness without motor, sensory, or autonomic symptoms. The gaze is blank, and communication is interrupted for a few seconds. Absence seizures are usually repeated throughout the day and correspond to what was formerly called petit mal ^[75].

• Other forms of generalized seizures :

Clonic, myoclonic, tonic and atonic seizures.

Partial (focal) seizures :

• Simple partial seizures :

In the motor form, known as Bravais-Jacksonian ^[189], the seizure begins with localized motor signs that spread gradually according to progression across the contralateral primary motor cortex ^[185].

Other types of simple partial seizures are non-motor, involving sensory, autonomic, or psychic disturbances.

• Complex partial seizures :

With disturbances of consciousness, which may or may not be associated with automatisms ^[187].

• Partial seizures with secondary generalization ^[183].

Begin as a localized focal discharge - often felt as a brief aura - before rapidly evolving into a global electrical storm that engulfs both hemispheres.

Diagnosis :

First, confirm the diagnosis of epilepsy and identify its underlying cause. Exclude all non-epileptic mimics to ensure an accurate diagnosis. ^[188]: hysteria, vasovagal syncope, breath-holding spells, syncope, tetany, or spasmophilia, using appropriate examinations.

The diagnosis of epilepsy relies on:

Electroencephalogram (EEG) :

The EEG ^{[5, 185]} helps highlight interictal abnormalities (between seizures) and sometimes records the seizures themselves. Ideally, the EEG should be coupled with a video recording ^[187].

A normal EEG does not formally rule out the diagnosis of epilepsy ^[69], and it may need to be repeated. In cases of severe epilepsy, a long-term recording coupled with video over one or several days in a specialized center may be necessary.

Neuroimaging :

These are not always indispensable ^[188]. If a lesion is suspected, an MRI (Magnetic Resonance Imaging) can show abnormalities that simple X-rays or CT scans cannot detect. Other imaging techniques may be proposed, especially if surgery is considered.

Treatment :

The treatment of epilepsy often requires a multidisciplinary approach (pharmacological, psychological, social, and sometimes even surgical) ^[31].

The two imperatives of anti-epileptic treatment are total seizure control and the absence of side effects. Therapeutic choices depend on a precise evaluation of the seizure type. They also depend on the patient's psychological profile and medical-social condition.

Therapeutic management relies primarily on anti-epileptic drugs ^[31] (or anticonvulsants): barbiturates (e.g., phenobarbital), benzodiazepines (diazepam, clonazepam), sodium valproate, phenytoin, carbamazepine, etc. Each product is preferentially active against one or a few varieties of epilepsy, and its goal is to prevent new seizures or reduce their frequency.

Benzodiazepines are the first-line emergency medications for epileptic seizures (convulsions) or status epilepticus.

For certain forms of drug-resistant epilepsy, primarily partial ones, surgical intervention may be considered ^[188] (cortectomies or disconnections).