Generalized tonic-clonic seizure: its symptoms and characteristics

Of all the seizures that a person can have 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 have, it is the most prototypical, and in this article we will 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 there are both tonic and clonic contractions of the muscles. This variety of seizures is the most associated with the prototypical image of an epileptic seizure, and is usually associated with metabolic dysregulations in the body of the person suffering from it.

It is usually believed that people who suffer from epilepsy only have this type of seizure, but the truth is that only 10% of epileptic patients suffer from this type of seizure 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.

Even if most cases seizures appear without warningSuddenly and abruptly, some people may 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 augur a crisis.

Once the seizures have started, there are up to three different phases during the seizure, 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 consciousness, although it is not always given in full.

Skeletal muscles tense, causing the extremities to remain rigid and the patient falls to the ground because he cannot stand.

The eyes roll or stop being directed at a specific point, and the mouth remains open.

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

The skin turns blue, due to the fact that the breath has lost its rhythmicity and there is a deprivation of oxygen in the organism.

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

One of the risks during the tonic phase is that of biting the tongue, since the jaw is clenched very strongly. 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 phase, which is a state in which the tension experienced during the previous phase it gives way to muscle relaxation. Lasts longer than the tonic phase, lasting about a minute.

Relaxation is not complete, since muscles immediately tense 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. It can also be rolled 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 may see its blood circulation altered, in addition to altering the levels of neurotransmitters.

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

It is quite probable that the person, after having suffered physically and psychologically during the episode, will cry and vomit.

Possible causes

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

However, it has been seen that certain types of seizures that occur unilaterally at the cerebral level, only involving one of the two hemispheres, they can evolve into crises that involve both hemispheres, thus giving a tonic-clonic seizure. Thus, we speak of unilateral focal seizures that evolve into more complex and bilateral seizures.

It has been hypothesized that certain dysregulations at the level of neurotransmitters and chemicals present in the central nervous system would be behind the appearance of this type of seizure. Some triggers of this type of crisis, in addition to certain genetic predisposition to suffer them, are fatigue, malnutrition, sleep deprivation, stress, hypertension, 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, tonic-clonic seizures have been replicated under laboratory conditions and also apparently therapeutic generalized.

In the case of people suffering 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 of the crisis are produced.

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 record brain activity while on or immediately after the tonic phase of the crisis.

During the tonic phase, there is a progressive increase in low-voltage brain activity, with fast waves, followed by high-amplitude electrical discharges. On the other hand, during the clonic phase there are short waves. The EEG is shown with many spikes during the tonic phase, and later on to a more irregular synalepha during the clonic phase.

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

Treatment

When a person has generalized tonic-clonic seizures, those around them should make sure that the person suffering from them is in a reclining posture, to avoid that, while losing consciousness, accidentally enter saliva into the airways and suffocate.

You must be close to the person to see how the epileptic episode is taking place and 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 either to hold the person while they are convulsing or to insert objects into the mouth, as it can contract the limbs, herniate and, if something is put in the mouth, choke on it.

Regarding treatment, as with other types of epileptic seizures, to avoid 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 prevent the nutritional conditions that contribute to a higher incidence of these crises from occurring, opts 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