Generalized tonic-clonic seizure: its symptoms and characteristics

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

Although this is not the only type of seizure that people with epilepsy may suffer from, it is the most prototype, and in this article we will learn more about its peculiarities, as well as the causes and possible treatments.

    Generalized tonic-clonic seizure: what is it?

    Generalized tonic-clonic seizure, also called “ grand malament ”, Is a type of epileptic seizure in which both tonic and clonic muscle contractions occur. This seizure variety is most associated with the prototypical picture of epileptic seizures and is often associated with metabolic imbalance in the victim’s body.

    It is generally believed that people with epilepsy only suffer from this type of seizure, but the truth is that only 10% of epilepsy patients experience this type of seizure without being accompanied by other varieties.


    The person may have several symptoms before, during, and after a generalized tonic-clonic epileptic seizure.

    Again in most cases, seizures appear without warningSuddenly and suddenly, some people may suffer from a prodrome. He warns that something is wrong with his body and that he will be suffering from an epileptic fit. Usually, the prodrome manifests itself in the form of premonitory feelings that predict that a seizure has been experienced.

    Once the seizures have started, up to three different phases occur during the epileptic seizure, which are the tonic phase, the clonic phase and the postcritical phase.

    1. Tonic phase

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

    The first thing that happens is the rapid loss of consciousness, Although not always given in full.

    Tense skeletal muscles, Keep the limbs stiff and the patient to fall to the ground so that they cannot stand up.

    The eyes go blank or stop pointing to a particular point and the mouth opens.

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

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

    The sympathetic system responds with force, Causing increased blood pressure, faster thawing of the heart and dilation of the eye pupil (mydriasis).

    One of the risks during the tonic phase is that the tongue bites, because the jaw is tightened very tightly. It can also bite your cheek and injure your mouth.

      2. Clonal phase

      After the tonic phase comes the clonic, which is a state in which the tension felt during the previous phase gives way to muscle relaxation. For more than the tonic phase, for about a minute.

      Relaxation is not complete, because the muscles immediately tighten again and then relax, Thus causing the seizures themselves.

      The person is violently shaken, at this point being the time when they can injure themselves against objects found in the room. It can also be rolled up while lying on the floor.

      3. Postictal phase

      Once the tonic and clonic phases have occurred, comes the post-critical phase, in which several events can occur.

      The patient’s brain may see impaired blood flow, In addition to altering the levels of neurotransmitters.

      The person is completely confused, in addition to suffering from amnesia, although they will gradually realize that they have had a seizure.

      It is very likely that the person, after suffering both physically and psychologically during the episode, will start to cry and vomit.

      Possible causes

      Although epilepsy has been studied extensively, it is known that most seizures associated with this problem are of the idiopathic typeIn other words, they suddenly appear without a clear reason as to why they appeared.

      However, we have seen that certain types of epileptic seizures that occur unilaterally at the cerebral level, involving only one of the two hemispheres, they can progress to crises involving both hemispheres, thus giving rise to a tonic-clonic crisis. Thus, we speak of unilateral focal epileptic seizures which progress to more complex and bilateral seizures.

      It has been hypothesized that certain deregulations in the neurotransmitters and chemicals present in the central nervous system are at the origin of such crises. Some triggers of this type of crisis, in addition to certain genetic predispositions to sufferThese are fatigue, malnutrition, sleep deprivation, stress, hypertension, diabetes, rapid light changes (blinking and blinking), high estrogen levels, and antihistamines.

      Throughout the history of psychiatry, with the use of electroconvulsive treatments for different types of psychological disorders, generalized tonic-clonic seizures have been able to be reproduced under laboratory conditions and also apparently therapeutic.

      In the case of people with symptomatic epilepsy, it has been observed, using neuroimaging techniques, that they present neurons with lesions, which causes them to transmit nerve signals incorrectly and thus the movements proper to the crisis are produced.


      the diagnosis this can be done through the use of neuroimaging techniques, Especially with electroencephalography (EEG). However, it must be said that in order for the diagnosis to be reliable with this tool, it is necessary to record brain activity while it is taking place or immediately after the tonic phase of the seizure.

      During the tonic phase, there is a gradual increase in low-voltage brain activity, with fast waves, followed by high-amplitude electric shocks. In contrast, short waves occur during the clonal phase. The electroencephalogram is shown with many peaks during the tonic phase, and then switch to a more irregular sinalefa during the clonic phase.


        When a person suffers from generalized tonic-clonic seizures, those around him must make sure that the person suffering from them is a lying posture, To prevent him from accidentally getting saliva into the airways and suffocating on passing out.

        You need to be close to the person to see how the epileptic episode is going and how long it lasts during the seizure. If possible, all objects should be removed from the site to prevent the person from colliding with them. Holding the person in convulsions or putting objects in the mouth is not recommended as they can contract limbs, hernia and, if something is put in the mouth, drown with them.

        As for treatment, as with other types of epileptic seizures, anticonvulsant drugs are prescribed to prevent them. In addition, in the event that the area of ​​the brain involved in the onset of these seizures is known, surgery may be performed, in addition to stimulating the vagus nerve.

        To avoid the nutritional conditions that contribute to a higher incidence of these seizures, the dietary path is chosen, subjecting the person to a ketogenic diet, that is, high in fat and protein.

        Bibliographical references:

        • Krumholz, A., Wiebe, S., Gronseth, G., et al. (2007). Practice parameter: evaluation of a first apparent unprovoked seizure in adults (a review evidence): Report of the American Academy of Neurology and American Epilepsy Society Neurology Quality Standards Subcommittee, 69 (21). 1996-2007.
        • Schachter SC (2009). Convulsive disorders. Med Clin North Am. 93 (2), 342-351

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