Generalized tonic-clonic seizure: its symptoms and characteristics

Of all the seizures that a person can suffer during an epileptic seizure, generalized tonic-clonic seizure It is probably the best known in popular culture.

Although it is not the only type of seizure that people with epilepsy can experience, it is the most prototypical, and in this article we are going to learn more about its particularities, as well as possible causes and treatments.

• Related article: "Epilepsy: definition, causes, diagnosis and treatment"

Generalized tonic-clonic seizure: what is it?

Generalized tonic-clonic seizure, also called 'grand mal', is a type of epileptic seizure in which both tonic and clonic muscle contractions occur. This variety of seizure is the one most associated with the prototypical image of an epileptic seizure, and is usually associated with metabolic deregulations in the body of the person who suffers from it.

Normally it is believed that people who suffer from epilepsy only suffer this type of crisis, but the truth is that only 10% of epileptic patients suffer from this type of seizures without being accompanied by other varieties.

Symptoms

There are several symptoms that the person can suffer before, during and after suffering generalized tonic-clonic seizures.

Although the majority of cases the seizures appear without warning, suddenly and abruptly, some people can suffer a prodrome. This warns that something is not going well in your body, and that you will suffer an epileptic seizure. Normally, the prodrome manifests itself in the form of premonitory feelings that portend that a crisis is going to occur.

Once the seizures start, there are up to three different phases during the epileptic crisis, which are the tonic phase, the clonic phase, and the postictal phase.

1. tonic phase

Usually, the tonic phase is the first of the phases when you have this type of seizure.

The first thing that happens is the rapid loss of consciousnessalthough it is not always complete.

Skeletal muscles tense, causing the extremities to become rigid and the patient to fall to the ground due to not being able to stand.

The eyes go blank or stop directing towards a specific point, and the mouth remains open.

This phase only lasts about ten or twenty seconds. and despite the loss of consciousness, the person is able to articulate some sounds, mostly due to the violent expulsion of air from the lungs. This is known as an ictal cry.

The skin turns blue, because breathing has lost its rhythm and there is a deprivation of oxygen in the body.

The sympathetic system responds forcefully, causing blood pressure to increase, the heart to beat faster, and the pupil of the eye to expand (mydriasis).

One of the risks during the tonic phase is that you bite your tongue, since the jaw is clenched very tightly. You can also bite your cheek and cause a large mouth injury.

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2. clonic phase

After the tonic phase comes the clonic one, which is a state in which the tension experienced during the previous phase it gives way to muscle relaxation. It lasts longer than the tonic phase, lasting about a minute.

The relaxation is not complete, since muscles immediately tighten again and then relax, thus causing the seizures themselves.

The person shakes violently, being in this phase the moment in which they can be injured against objects that are in the room. He can also roll while lying on the ground.

3. postictal phase

Once the tonic and clonic phases have occurred, the postictal phase comes, in which multiple events can occur.

The patient's brain can see its blood circulation altered, in addition to altering the levels of neurotransmitters.

The person is totally confused, in addition to suffering amnesia, although he will gradually become aware that he has suffered a crisis.

It is quite likely that the person, after having suffered physically and psychologically during the episode, will start crying and vomit.

Possible causes

Although epilepsy has been extensively studied, it is known that most seizures associated with this problem are idiopathic, that is, they appear suddenly without a clear cause that allows an explanation of the reason for their appearance.

However, it has been possible to see that certain types of epileptic seizures that occur unilaterally At the brain level, only involving one of the two hemispheres, they can evolve into seizures that involve both hemispheres, thus giving rise to a tonic-clonic seizure. Thus, we are talking about unilateral focal epileptic seizures that evolve into more complex and bilateral seizures.

It has been hypothesized that certain deregulations at the level of neurotransmitters and chemical substances present in the central nervous system would be behind the appearance of this type of seizures. Some triggers for this type of crisis, in addition to certain genetic predisposition to suffer themThese are fatigue, malnutrition, sleep deprivation, stress, high blood pressure, diabetes, rapid light changes (blinks and flashes), elevated estrogen levels, and antihistamines.

Throughout the history of psychiatry, with the use of electroconvulsive treatments for different types of disorders psychological, it has been possible to replicate in laboratory conditions and, also, apparently therapeutic, tonic-clonic seizures widespread.

In the case of people who suffer from symptomatic epilepsy, it has been seen, through neuroimaging techniques, that have damaged neurons, causing them to inappropriately transmit nerve signals and, thus, the movements typical of the crisis take place.

Diagnosis

The diagnosis can be done by using neuroimaging techniques, especially with electroencephalography (EEG). However, it must be said that for the diagnosis using this tool to be reliable, it is necessary to record brain activity while giving or immediately after the tonic phase of the crisis.

During the tonic phase, there is a progressive increase in low-voltage brain activity, with rapid waves, followed by high-amplitude electrical discharges. In contrast, short waves occur during the clonic phase. EEG shows many spikes during the tonic phase, to later change to a more irregular signal during the clonic phase.

• You may be interested in: "Types of brain waves: Delta, Theta, Alpha, Beta and Gamma"

Treatment

When a person has a generalized tonic-clonic seizure, those around them should make sure that the person having it is safe. a reclining posture, in order to avoid that, while losing consciousness, you accidentally introduce saliva into the respiratory tract and suffocate.

You must be close to the person to see how the epileptic episode is taking place and to estimate how long the seizure is lasting. If possible, all objects should be removed from the place to prevent the person from colliding with them. It is not recommended to hold the person while they are convulsing or to introduce objects into the person's mouth, since you can contract the extremities, get herniated and, if you put something in your mouth, choke on it.

Regarding treatment, as with other types of epileptic seizures, to prevent them, anticonvulsant drugs are prescribed. Also, if the brain area involved in the appearance of these crises is known, a surgical intervention can be carried out, in addition to stimulating the vagus nerve.

To avoid the occurrence of nutritional conditions that contribute to a higher incidence of these crises, opt for the dietary route, subjecting the person to a ketogenic diet, that is, high in fat and protein.

Bibliographic references:

• Krumholz, A., Wiebe, S., Gronseth, G., et al. (2007). Practice Parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology, 69(21). 1996-2007.
• Schachter S. c. (2009). Seizure disorders. Med Clin North Am. 93(2), 342-351