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    Absence Seizure (Absence Seizures)

    Absence seizures may occur to patients suffering from idiopathic or symptomatic generalized epilepsy. They imply brief unawareness of one's surroundings and are less common in adults than in children.

    This disease develops due to the following process: endocrine.


    An absence seizure typically consists of brief lapses of awareness, i.e. the patient will suddenly interrupt his or her doings, stare blankly into space and will not react to their surroundings. Sometimes rapid blinking of the eyelids or uncontrolled movement and jerking of an arm or a leg may be observed, too [12].

    These lapses of awareness generally last a few seconds. They are associated with amnesia, as the patient does not remember what happened during the seizure. Frequently, the patient just continues doing what he or she has been doing before the seizure. Since absence seizures generally do not imply physical harm nor confusion, they are not followed by a recovery period.

    Particularly in case of pyknoleptic CAE, the high frequency of absence seizures may hinder the child in his or her day-to-day activities, in paying attention to class, to sports, to games. Conversations with the child may frequently be interrupted by the child's attention "wandering". It is not uncommon that the child's teacher is the first person to notice something wrong. Either parents or teacher may complain about the child's lack of attention or about the child daydreaming because they are usually not familiar with absence seizures.

    Entire body system
    • Childhood absence epilepsy (CAE), also known as pyknolepsy, is an idiopathic generalized epilepsy which occurs in otherwise normal children.[]
    • Disorders, Absence , Convulsion, Petit Mal , Petit Mal Convulsion , Epilepsy, Minor , Minor Epilepsies , Minor Epilepsy , Pykno Epilepsy , Pykno-Epilepsies , Pykno-Epilepsy , Epilepsy, Absence [Disease/Finding] , absence epilepsy , epilepsy absence ,[]
    • This includes absence epilepsy, juvenile myoclonic epilepsy, and benign rolandic epilepsy.[]
    • epilepsy , and juvenile myoclonic epilepsy) ( Commission 1989 ).[]
    • Treating epilepsy in individuals with autism follows the same principles as treatment of epilepsy in any person.[]
    • The person may fall over.[]
    • Falling and jerking do not occur in typical absences.[]
    • After the seizure the person may be confused or injured from a fall.[]
    • During the course of falling asleep (stage 1, superficial stage 2) spike-wave discharges show the ictal absence type activation (even if in awake state they were not present).[]
    • No first aid is needed (unless there is injury from the fall), but if this is a first atonic seizure, the child should be given a thorough medical evaluation.[]
    • This type of seizure is associated with fever and is not epilepsy, although a fever may trigger a seizure in a child who has epilepsy.[]
    • When a child only has a single seizure and no history of them, it may be a result of other conditions, such as a high fever or injury.[]
    • For example, a high temperature (fever) may cause a febrile convulsion.[]
    • ., fright or anger), fever, or other hypermetabolic states, hypoglycemia, hypocalcemia, hypomagnesemia, hypoxemia, and toxic states (e.g., tetanus, uremia, exogenous, excitatory agents such as amphetamine, aminophyline, lidocaine, penicillin) are a few[]
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  • neurologic
    Behavior Problem
    • problems Social isolation Oct. 05, 2017[]
    • Compared to those without seizures, children with ASD and seizures are also more likely to have sleep difficulties and behavior problems.[]
    • Educational and behavioral problems are sequelae of frequent, unrecognized seizures.[]
    • This type of seizure is sometimes mistaken for a learning problem or behavioral problem.[]
    • Although absence seizures can occur in typical children, children with CAE have higher rates of behavioral, social, and educational problems, and a third of the children with CAE present with attention deficit. [ Glauser: 2010 ] Behavioral problems and[]
    • A sensory or psychic phenomena may be emotional (e.g. fear, anxiety), physical (e.g. dizziness, nausea), or sensory (e.g. tingling or crawling sensation on the skin, spots or colours before the eyes, strange tastes or smells).[]
    • Relatively common side effects include mild fatigue, abdominal discomfort or dizziness.[]
    • […] undiagnosed : Although the symptoms of severe brain injury are hard to miss, it is less clear for milder injuries, or even those causing a mild concussion ... read more » MTBI misdiagnosed as balance problem : When a person has symptoms such as vertigo or dizziness[]
    • Hyperventilation is an unnatural state in which people feel dizzy, “tingly,” and uncomfortable and often develop dry lips and mouth.[]
    Drop Attack
    • […] drowsiness for minutes to hours after Myoclonic Seizures sudden, brief, almost instantaneous jerks of the body or parts of the body children with infantile spasms have clusters of myoclonic jerks that tend to occur when they awaken Atonic Seizures or Drop[]
    • A sudden fall to the ground ('drop attack') can occur with myoclonic, tonic or atonic seizures or a focal seizure involving the movement areas.[]
    • Other names for this type of seizure include drop attacks, astatic or akinetic seizures.[]
    • Atonic (also called a drop attack) : Atonic seizures cause loss of muscle tone.[]
    • An atonic seizure is sometimes called a "drop attack."[]
    • These mutations cause increased channel activity and associated increased neuronal excitability.[]
    • In a vacuum, this would soon lead to out-of-control mutual excitement, similar to a microphone being placed too close to a P.A. speaker.[]
    • A seizure focus is an area of abnormal electrical excitability in the cerebral cortex. 22-1.[]
    • This strong feedback was consequent to an increased cortical excitability, and thus, such a system could generate spike-and-wave oscillations, and a progressive transformation from spindle to spike-and-wave activity as cortical excitability was increased[]
    • . 8 Although ethosuximide’s mechanism of action is not fully understood, the blockade of a specific voltage-gated calcium channel (the T channel) in thalamic neurons appears integral to its antiepileptic activity. 7 This blockade suppresses thalamic excitability[]
    Generalized Seizures
    • Absence seizures are one form of generalized seizure.[]
    • -Primary Generalized Epilepsies can present with various generalized seizures.[]
    • Generalized Seizures Generalized Seizures occur when there is widespread seizure activity in the left and right hemispheres of the brain.[]
    • The two most common forms of generalized seizures are: Generalized seizures (grand mal seizures) Absence seizures (petit mal seizures) Both forms of generalized seizures cause a temporary loss of consciousness.[]
    Involuntary Movements
    • This may result in a loss of consciousness, convulsions or other involuntary movements.[]
    Myoclonic Jerking
    • Myoclonic jerks often happen in the first few hours after waking up and can occur in combination with other types of generalised seizures.[]
    • jerks of upper limbs with tonic abduction.[]
    • The majority of children with pure absence epilepsy will remit with time whereas those with other forms of typical absence syndromes, such as juvenile myoclonic and absence epilepsy , might develop lifelong myoclonic jerks and generalised tonic-clonic[]
    • […] jerking of the body occurs about 30 seconds later clonic phase confusion or drowsiness for minutes to hours after Myoclonic Seizures sudden, brief, almost instantaneous jerks of the body or parts of the body children with infantile spasms have clusters of myoclonic[]
    • Some absence seizures are accompanied by brief myoclonic jerking of the eyelids or facial muscles, or by variable loss of muscle tone.[]
    • Mechanisms of absence seizures (Scholarpedia)[]
    • Seizure Types There are several different types of seizures, seizure disorders or epilepsy types.[]
    • Focal seizures used to be called partial seizures.[]
    • These seizures combine the characteristics of tonic seizures and clonic seizures.[]
    • Typical Absence Seizures These seizures are the most common.[]
    Staring Spells
    • So they look like a sort of eye roll or an eye deviation and a staring spell.[]
    • So if a middle-aged person has staring-spell seizures, they are almost always of the partial-complex type.[]
    • Absence seizure: A seizure that takes the form of a staring spell.[]
    • Petit mal seizures take the form of a staring spell: the person suddenly seems to be "absent."[]
    • Definition An absence seizure is the term given to a staring spell.[]
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  • Workup

    Since absence seizures are characterized by lapses of awareness, by the patient staring off into space, differential diagnoses have to be excluded. Those may include metabolic disorders and intoxications. A detailed medical history may give initial indications regarding the nature of those staring spells. If metabolic anomalies or an intoxication are presumed, laboratory tests may be required to confirm or rule out this possibility.

    In case of absence seizures, an EEG may be diagnostic and usually shows features characteristic of certain types of epilepsy. In order to produce these features, it may be helpful to provoke an absence seizure. Therefore, the patient may be stimulated with flickering lights or just asked to breathe rapidly. A thorough analysis of the EEG should be carried out to identify the precise type of epilepsy and maybe even its cause.

    If an EEG does not yield conclusive results or if organic anomalies are suspected, a brain scan may be indicated. Magnetic resonance imaging (MRI) is the method of choice to detect malformations, neoplasias and other pathological structures that may cause epilepsy [13].

    Test Results

    Seizure Activity
    • Absence seizure activities induced by the slow kinetics of receptors in TRN.[]
    • The limbic cortex has the lowest cortical threshold for initiating and sustaining seizure activity.[]
    • activity in both hemispheres of the brain) is about to occur.[]
    • Your seizure diary will help a neurologist see any patterns in seizure activity.[]
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  • Laboratory

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  • Treatment

    Anti-epileptic treatment should aim at finding the appropiate dose for each individual requiring therapy. Here, the appropiate dose referes to a dose as high as necessary and as low as possible. Usually, treatment starts with a low dose that progressively increases until seizures are under control.

    It is recommended to continue treatment until long after the last seizure, because relapses are frequent and often include tonic-clonic seizures. A seizure-free period of two years may justify therapy discontinuation, but decisions have to be taken on a case by case basis.

    Absence seizures may be treated with the following drugs:

    • Ethosuximide. This drug mediates its anticonvulsant effect by blocking low voltage-gated calcium channels. It is the drug of choice to treat absence seizures. Most patients respond well to this treatment [14].
    • Valproate. In cases refractory to ethosuximide, valproate may be an alternative. It is, however, associated with a higher risk of birth defects in babies and should therefore be administered with caution to women.
    • Lamotrigine. This anti-epileptic channel blocker may be less effective than ethosuximide and valproate, but has also fewer side effects [15].
    • Zonisamide. This anticonvulsant has been recommended to treat typical absence seizures and refractory primary generalized epilepsy [16].
    • Levetiracetam. Levetiracetam is a derivative of the nootropic piracetam and is indicated for JME [17]. It is currently being investigated for effectivity in CAE or JAE.
    • Topiramate. Although this anticonvulsant has been used to treat generalized tonic-clonic seizures, data regarding its effect in absence epilepsy is rare [16]. It may be used as adjunctive therapy in cases of the Lennox-Gastaut syndrome


    The distinct forms of absence epilepsy are associated with different prognoses. In general, young age at onset, physiological EEG background signals and satisfying response to therapy are good prognostic signals.

    Patients suffering from CAE generally respond well to treatment and remission is possible. However, up to 40% of children diagnosed with CAE do develop tonic-clonic seizures. Should that be the case, chances for complete remission decrease.

    Although the probability of ocurrence of tonic-clonic seizures is high in adolescents diagnosed with JME, they usually respond well to anti-epileptic treatment. Only few cases may be resolved by lifestyle adaptation (abstinence from alcohol, well controlled sleep regimen) and the majority of patients requires treatment for life because the relapse rate is >90% [11].


    Absence Seizure
    • Mechanisms of absence seizures (Scholarpedia)[]
    • Misdiagnosis of Absence seizure Failure to diagnose Absence seizure Hidden causes of Absence seizure (possibly wrongly diagnosed) Undiagnosed: Absence seizure Absence seizure: Complications Review possible medical complications related to Absence seizure[]
    Febrile Convulsions
    • For example, a high temperature (fever) may cause a febrile convulsion.[]
    • It is often associated with prolonged febrile convulsions in early childhood.[]
    • convulsions, generalized tonic-clonic seizures).[]
    • Affected family members may have other forms of idiopathic or generalized epilepsy, such as febrile convulsions and generalized tonic-clonic seizures.[]
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  • Etiology

    Epileptic seizures are triggered by abnormal or excessive electrical activity in the brain that is, in turn, caused by disorders in electrolyte and neurotransmitter balance [4]. Sometimes this abnormal electrical acitivity is compared to cerebral short circuits. In an EEG, seizures are often characterized by abnormal, repetitive patterns.

    Generally, no direct triggers can be identified. It has been reported that hyperventilation may provoke an absence seizure. Also, genetic predisposition seems to play an important role, especially in children [5]. However, the majority of children suffering from absence seizures does overcome them when growing up. Of note, some children with absence seizures may also develop tonic-clonic seizures.


    Epidemiological studies regarding absence seizures and those forms of epilepsy that may involve them are complicated by the existence of distinct classification systems.

    Thus, the following data should merely provide orientation regarding the incidence of different forms of absence epilepsy. For children and adolescents younger than 18 years, studies conducted in the US showed that 4,000 cases of individuals with absence epilepsy and 1,500 individuals with JME were diagnosed each year [6]. 

    Studies regarding the incidence of idiopathic generalized epilepsies have been carried out. In this context, an incidence of up to 8 per 100,000 inhabitants has been estimated for CAE [7]. Prevalence of CAE is highest in children aged 2 to 9 years and is of up to 0.7 per 1,000 persons. Girls are affected significantly more often than boys. With regards to JAE, less data is available. The disease is usually diagnosed in adolescents aged 10 to 17 years and its prevalence has been estimated to be about 0.1 per 100,000 persons [8]. JME is also diagnosed in adolescents, mainly in those aged 12 to 18 years, and the incidence is of approximately 1 per 100,000 inhabitants [7]. Thus, JME is diagnosed more frequently than JAE, but less often than CAE. Similar to CAE, females seem to be affected more often. The prevalence has been estimated to be up to 0.2 per 2,000 persons. It has been speculated that JME does occur less frequently in developing countries.

    With regard to symptomatic generalized epilepsies, few data is available regarding epilepsies with myoclonic absences and the Lennox-Gastaut syndrome [9]. Interestingly, a male preponderance has been reported for epilepsies with myoclonic absences and the Lennox-Gastaut syndrome . The incidence of the Lennox-Gastaut syndrome has been estimated to be about 2 per 100,000 persons.

    Sex distribution
    Age distribution


    Current knowledge regarding pathophysiologic processes behind absence seizures is mainly derived from animal models. These animal models are based on a reverberating circuit generating abnormal, oscillating rhtyhms between cortex and thalamus. In an EEG, characteristic spike and wave complexes can be seen.

    The reticulothalamic nucleus of the thalamus contains inhibitory gabaergic interneurons. Prolonged opening of the GABA-receptor is presumably associated with an increased influx of chloride ions and leads to hyperpolarization. Low voltage-gated calcium channels are active at such low membrane potentials, may cause rebound depolarization and trigger absence seizures. Indeed, absence seizures may be treated with ethosuximide, a drug blocking such calcium channels.

    Because genetic predisposition does play an important role in the development of absence seizures, several studies have been carried out to identify those genes that contribute to idiopathic generalized epilepsies such as CAE, JAE and JME. Not surprisingly, genes that were proven to affect the incidence of idiopathic generalized epilepsies, encode for ion channels. Polymorphisms affecting the expression of GABA receptors and voltage-gated calcium channels may be responsible for CAE and JME. Furthermore, mutations in genes encoding voltage-gated chloride channels have been associated with CAE, JAE and JME. Certain types of absence epilepsies have been related to mutations affecting the expression of the neuronal nicotinic acetylcholine receptor and the GLUT1 glucose transporter [10].


    No preventive strategies have been identified.


    Patients suffering from in idiopathic or symptomatic generalized epilepsy may have absence seizures [1].

    Childhood absence epilepsy (CAE), juvenile absence epilepsy (JAE) and juvenile myoclonic epilepsy (JME) are idiopathic generalized epilepsies that may involve typical absence seizures. In electroencephalography (EEG), generalized 3-4 Hz spike and slow wave complexes indicate an absence seizure. Seizures are pyknoleptic in childhood absence epilepsy, i.e. they occur frequently up to several times a day, but only last a few seconds. On the other hand, in epilepsies with later onset, absence seizures usually occur less often but last longer. They are therefore of non-pyknoleptic or spanioleptic nature. Myoclonic and tonic-clonic seizures may be associated with these idiopathic generalized epilepsies, but are seldom observed in forms with an early onset.

    Contrary to idiopathic generalized epilepsies, absence seizures in symptomatic generalized epilepsies are represented by 1.5-2-5 Hz slow spike and wave complexes [2]. They are therefore termed atypical absence seizures. Since these absence seizures may involve decrease or increase of muscle tone, patients may fall during a seizure.

    According to the recommendations of the International League Against Epilepsy, absence seizures are now classified as typical, atypical or special, whereby absence seizures with special features include myoclonus [3].

    Patient Information

    Absence seizures are associated with certain forms of epilepsy. They generally last only a few seconds and do involve brief periods of time when an indicidual lapses out of awareness. They are most frequently observed in children.


    While some genetic variants have been identified that contribute to the development of absence seizures, no direct causes could be determined so far. It has been proposed that flickering lights and rapid breathing may trigger an absence seizure, but that may be limited to genetically predisposed persons.

    Some types of epilepsy associated with absence seizures mainly affect young children, whereas others are more frequently observed in adolescents. Depending on the exact type of epilepsy, further symptoms may be present.


    The person suffering an absence seizure usually interrupts what they are doing, stares into space and resumes his or her activities after some seconds. During the seizure, the patient neither speaks nor responds to their surroundings. In some cases, the affected person blinks rapidly.

    Absence seizures are typically not associated with changes in muscle tone, although these may be the case in certain forms of epilepsy. Also, absence seizures may be accompanied by myoclonic or tonic-clonic seizures that involve twitching and jerking.


    Because absence seizures mainly affect children, they are sometimes simply referred to as staring spells or wandering attention. It is not uncommon for parents or teachers to attribute them to child behavior rather than to a medical problem like epilepsy.

    A detailed medical history may therefore be given if a physician is consulted. While blood tests may be conducted to rule out other causes for the observed brief losses of awareness, an EEG is usually diagnostic for epilepsy. In an EEG, the brain's electrical activity is recorded. In cases of epilepsy, these recordings show specific alterations. If needed, a brain scan may be carried out for further diagnostics.


    Because absence seizures may impair the patient's ability to partake in day-to-day activities, school or even work, they should be treated with anti-epileptic drugs. Ethosuximide, valproate and lamotrigine are only some of the currently available alternatives. Most people suffering from absence seizures respond well to treatment. It may be necessary to take more than one drug if other types of seizures are experienced.

    An anti-epileptic therapy is usually a long-term treatment that should be continued even if the patient has been seizure-free for some time. The decision to discontinue treatment should be taken by the physician, not by the patient.


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