Types of epilepsies: causes, symptoms and features

Epilepsy can be classified into different categories according to its symptoms and signs.

Epileptic seizures are complex phenomena, especially considering that there are different types of epilepsy..

References to epilepsy are already found in the Bible and even in older Babylonian documents, which at the time were called morbus sacer or sacred disease, which caused people to lose consciousness, fall to the ground and suffer major convulsions while sunbathing. and suffered major convulsions while foaming at the mouth and biting their tongues..

As can be imagined from the name originally given to it, it was associated with religious elements. it was associated with religious or magical elements.It was considered that those who suffered from it were possessed or were in communication with spirits or gods.

With the passing of the centuries, the conception and knowledge of this problem was broadened, finding that the causes of this problem lie in the functioning of the brain. But the term epilepsy does not refer only to the type of seizures mentioned above, but actually includes different syndromes. Thus, we can find different types of epilepsy.

• To learn more: "What is epilepsy and how can this neuropathology be treated?"

A disorder of neurological origin

Epilepsy is a complex disorder whose main characteristic is the presence of repeated nervous seizures over time in which one or more groups of hyperexcitable neurons are activated abruptly, continuously, abnormally and unexpectedly, causing an excess of activity in the hyperexcited areas leading to loss of control of the nervous system. leading to loss of control of the organism.

It is a chronic disorder that can be generated by a large number of causes, some of the most frequent being traumatic brain injury, stroke, hemorrhage, infection or tumors. These problems cause certain structures to react abnormally to brain activityThese problems cause certain structures to react abnormally to brain activity and may lead to the presence of secondary epileptic seizures.

One of the most common and recognizable symptoms are seizures, violent and uncontrollable contractions of voluntary muscles, but despite this only occur in some types of epilepsy. The specific symptoms of the epileptic person depend on the hyperactivated area where the seizure starts. However, epileptic seizures are broadly similar, since their action extends to almost the entire brain.

Types of epilepsy according to whether their origin is known

When classifying the different types of epilepsy we have to take into account that not in all cases it is known what causes them. In addition, they can also be grouped according to whether or not their causes are known, there being three groups in this sense: symptomatic, cryptogenic and idiopathic.

A) Symptomatic crises

Symptomatic seizures are seizures whose origin is known.. This group is the best known and most frequent, being able to locate one or several epileptoid areas or brain structures and a damage or element that causes such alteration. However, at a more detailed level, it is not known what produces this initial alteration.

B) Cryptogenic seizures

Cryptogenic seizures, nowadays probably called symptomatic seizures, are those epileptic seizures suspected of having a specific cause. are suspected of having a specific cause, but whose origin cannot yet be demonstrated by evaluation techniques. current. It is suspected that the damage is at the cellular level.

C) Idiopathic seizures

Both in the case of symptomatic and cryptogenic seizures, epilepsy is caused by hyperactivation and anomalous discharge of one or several groups of neurons, activation coming from a more or less known cause. However, it is sometimes possible to find cases in which the origin of epileptic seizures does not seem to be due to a recognizable damage.

This type of seizure is called idiopathic, which is believed to be due to genetic factors.. Although their origin is not known exactly, people with this type of seizures tend to have a generally good prognosis and response to treatment.

Types of epilepsy according to generalization of seizures

Traditionally, the presence of epilepsy has been associated with two basic types called grand mal and petit mal, but research over time has shown that there are a wide variety of epileptic syndromes. The different seizure syndromes and types of epileptic seizures are classified are mainly classified according to whether the discharges and neural hyperexcitation occur only in a specific area or at a generalized level..

1. Generalized seizures

In this type of epileptic seizures the electrical discharges coming from the brain are provoked bilaterally in a certain area to end up generalizing to all or great part of the brain. In these types of epilepsy (especially in grand mal seizures), an aura is often present before the seizure.The first symptoms, i.e., prodromes or symptoms such as dizziness, tingling and hallucinations at the onset of the seizure, can prevent the person who is going to suffer it from its occurrence. Some of the best known and iconic within this type of epileptic seizures are the following.

1.1. Generalized tonic-clonic seizures or grand mal seizures

The prototypical epileptic seizure, in grand mal seizures, there is a sudden and abrupt loss of consciousness that causes the patient to fall to the floor, and is accompanied by constant and constant seizures.It is accompanied by constant and frequent convulsions, biting, urinary and/or fecal incontinence and even screaming.

This type of seizure is the most studied, having found three main phases during the seizure: first the tonic phase in which there is loss of consciousness and the fall to the ground, then the clonic phase in which the seizures appear, and then the clonic phase in which the seizures (starting at the extremities of the body and becoming progressively generalized) and finally culminating the epileptic seizure with the recovery phase in which consciousness is gradually regained.

1.2. Absence seizures or petit mal seizures

In this type of epileptic seizure, the most typical symptom is the loss or alteration of consciousness, such as small interruptions in the activity of the seizure.In this type of epileptic seizure, the most typical symptom is the loss or alteration of consciousness, such as small stops of mental activity or mental absences accompanied by akinesia or lack of movement, without other more visible alterations.

Although the person loses consciousness temporarily, the person does not fall to the floor and does not usually have physical alterations (although sometimes there may be contractions in the facial muscles).

1.3. Lennox-Gastaut syndrome

This is a subtype of generalized epilepsy typical of childhood, in which mental absences and frequent seizures appear in the first years of life (between two and six years of age) that generally occur together with intellectual disability and personality, emotional and behavioral problems. It is one of the most serious neurological disorders in children, and can cause death in some cases either directly or by in some cases either directly or due to complications associated with the disorder.

1.4. Myoclonic epilepsy

Myoclonus is a jerky, abrupt movement involving the displacement of a body part from one position to another.

In this type of epilepsy, which actually includes several sub syndromes such as juvenile myoclonic epilepsy, it is common for seizures and fever to appear more and more frequentlywith some focal seizures in the form of jerks on awakening from sleep. Many people with this disorder end up presenting with grand mal seizures. It frequently appears as a reaction to light stimulation.

1.5. West syndrome

A subtype of infantile generalized epilepsy with onset in the first half of life, West syndrome is a severe disorder.West syndrome is a severe and rare disorder in which children have disorganized brain activity (visible by electroencephalogram).

Children with this disorder suffer from bouts of spasms that mostly cause inward flexion of the limbs, their full extension or both. Its other main characteristic is the psychomotor degeneration and disintegration of the infant, losing physical, motivational and emotional expression skills.

1.6. Atonic crises

They are a subtype of epilepsy in which loss of consciousness appears and in which the individual usually falls to the ground due to an initial muscular contraction, but without the appearance of seizures and recovering quickly. Although it produces brief episodes, it can be dangerous, since the falls can produce serious affectations due to trauma.

2. Partial/focal seizures

Partial epileptic seizures, unlike generalized seizures, occur in specific and concrete areas of the brain. In these cases the symptomatology varies greatly depending on the location of the hyperactivated donor, limiting the damage to that area, although in some cases the seizure may become generalized. Depending on the area, the symptoms may be motor or sensory, causing from hallucinations to seizures in specific areas.

These seizures can be of two types, simple (a type of epileptic seizure localized in a specific area, and which does not affect the level of consciousness) or complex (which do alter psychic abilities or consciousness).

Some examples of partial seizures are as follows

Jacksonian seizures

This type of seizure is due to hyperexcitability of the motor cortex, causing localized seizures at specific points which in turn follow the somatotopic organization of the motor cortex.

2.2. Benign partial epilepsy of infancy

This is a type of partial epileptic seizure that occurs during childhood. They usually occur during sleep and do not produce a serious disturbance in the development of the subject. They usually disappear on their own during the course of development, although in some cases they may develop into other types of epilepsy that are serious and affect the quality of life in many areas.

One last consideration

In addition to the types mentioned above, there are also other seizure-like seizure processes, such as in cases of dissociative and/or somatoform disorders, or seizures during fevers. However, although in some classifications they are included as special epileptic syndromes, there is some controversy, and some authors do not agree that they should be considered as such.

Bibliographic references:

• Abou-Khalil, B.W.; Gallagher, M.J. & Macdonald, R.L. (2016). Epilepsies. In: Daroff RB, Jankovic, J.; Mazziotta, J.C. & Pomeroy, S.K. (eds.). Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier::chap 101.
• Commission on Classification and Terminology of the International League Against Epilepsy. Proposal for revised clinical and electroencephalographic classification of epileptic seizures. Epilepsia. 1981;22:489-501.
• Engel, J. Jr. (2006). Report of the ILAE classification core group. Epilepsia;47:1558-68.