Absence Seizure

Obtain a first-hand witness history and, when available, smartphone video. Establish abrupt onset and offset, behavioral arrest, impaired responsiveness, duration, automatisms, precipitants, recovery, and any previous unrecognized events. Witness accounts and video can improve diagnostic accuracy; the before-during-after sequence is specifically useful for seizure-type discrimination. cks nice org ukcks nice org ukAssessment | Diagnosis | Epilepsy | CKS | NICE

Typical absence seizures usually last approximately 5 to 10 seconds, have minimal or no postictal confusion, and are commonly precipitated by hyperventilation; photic stimulation can also precipitate events. A longer confusional recovery, focal onset features, or an event that is not abrupt should reduce confidence in typical absence seizures and broaden the event differential before assigning a generalized epilepsy syndrome. BMJBMJAbsence seizures - Symptoms, diagnosis and treatment | BMJ Best Practice

Order routine EEG with activation procedures and seek capture of the habitual clinical event. Typical absence seizures have regular, symmetric generalized spike-and-wave at about 3 Hz during the ictus. EEG interpretation should include background organization, discharge frequency, polyspike-wave morphology, and photic response because these features help distinguish childhood absence epilepsy from adolescent generalized epilepsy syndromes. BMJ+1BMJAbsence seizures - Symptoms, diagnosis and treatment | BMJ Best PracticeWolters KluwerOutcome of Absence Epilepsy With Onset at 8-11... : Journal of Child Neurology

Childhood absence epilepsy is an idiopathic or genetic generalized epilepsy syndrome in an otherwise normal child with daily absence seizures and generalized spike-wave at 2.5 to 4 Hz. Commonly cited onset is age 4 to 10 years, with a peak at 5 to 7 years. A normal EEG background strengthens this classification; an abnormal background should prompt reconsideration because it is also associated with poorer long-term remission in typical childhood absence epilepsy cohorts. ScienceDirect+4ScienceDirectChildhood absence epilepsy: Elctroclinical features and diagnostic criteria - ScienceDirectScienceDirectChildhood Absence Epilepsy - an overviewWileyILAE definition of the Idiopathic Generalized Epilepsy ...Wolters KluwerOutcome of Absence Epilepsy With Onset at 8-11... : Journal of Child NeurologyNeurologyLong-term prognosis of typical childhood absence epilepsy

Juvenile absence epilepsy typically begins around puberty and is characterized by absences with generalized tonic-clonic seizures; some patients also have myoclonic jerks. Generalized spike-wave can range from 3 to 6 Hz, and a normal EEG does not by itself exclude juvenile absence epilepsy when the history is strongly typical. Because generalized tonic-clonic seizures are central to the syndrome phenotype, ethosuximide alone may leave clinically important seizure types untreated. PubMedPubMedJuvenile Absence Epilepsy - StatPearls - NCBI Bookshelf

Juvenile myoclonic epilepsy should be actively sought in adolescents with absence spells by asking about morning myoclonic jerks and generalized tonic-clonic seizures. Its EEG commonly shows generalized 3.5- to 6-Hz polyspike-wave, and photoparoxysmal response is reported in about one-third of patients. The absence presentation can precede readily apparent juvenile myoclonic epilepsy EEG features, so repeat clinical review for evolving myoclonus is important when the phenotype changes. Wolters Kluwer+1Wolters KluwerOutcome of Absence Epilepsy With Onset at 8-11... : Journal of Child Neurologynice org ukEpilepsies in children, young people and adults

For childhood absence epilepsy with absence seizures as the sole recognized seizure type, ethosuximide is a first-line option. It is identified as the optimal treatment option for new-onset childhood absence epilepsy in randomized dose-escalation work, and it is described as first-line therapy for childhood absence epilepsy. Its key tradeoff is narrow seizure-spectrum utility: the treatment choice must be revisited if generalized tonic-clonic or myoclonic seizures emerge. Wiley+1WileyModel‐Informed Precision Dosing Guidance of Ethosuximide ...WileyAn innovative ethosuximide granule formulation designed for ...

Valproate is an alternative first-line agent when the clinical history includes generalized tonic-clonic seizures or myoclonic seizures, because it treats generalized seizure phenotypes beyond absences. In a 14-week double-blind trial in childhood and juvenile absence epilepsy, valproate and ethosuximide were superior to lamotrigine; systematic review guidance similarly supports considering ethosuximide or valproate before lamotrigine for absence seizures. BMJ+2BMJAbsence seizures - Symptoms, diagnosis and treatment | BMJ Best PracticeThe LancetThe SANAD II study of the effectiveness and cost ...WileyNeuropharmacology of Antiseizure Drugs - Hakami - 2021

Lamotrigine is a reasonable alternative when ethosuximide or valproate is unsuitable, but clinicians should counsel that it had lower short-term efficacy than ethosuximide or valproate in comparative absence-epilepsy trials. In patients with a generalized epilepsy phenotype who could become pregnant, treatment selection requires individualized consideration of valproate risk-benefit tradeoffs; the reviewed pharmacology literature specifically identifies lamotrigine as a consideration in women. The Lancet+1The LancetThe SANAD II study of the effectiveness and cost ...WileyNeuropharmacology of Antiseizure Drugs - Hakami - 2021

Do not infer that any antiseizure medication effective for focal epilepsy is appropriate for an absence syndrome. The treatment target is the diagnosed generalized epilepsy syndrome and its complete seizure inventory, not simply the presenting stare. Reassess the history after any breakthrough event, especially for generalized tonic-clonic seizures or morning myoclonus that would make ethosuximide monotherapy inadequate. BMJ+2BMJAbsence seizures - Symptoms, diagnosis and treatment | BMJ Best PracticeWolters KluwerOutcome of Absence Epilepsy With Onset at 8-11... : Journal of Child NeurologyPubMedJuvenile Absence Epilepsy - StatPearls - NCBI Bookshelf

At each follow-up, obtain event frequency from caregivers, teachers, and the patient; ask separately about unrecognized brief arrests, generalized tonic-clonic seizures, and early-morning myoclonus. Continued or newly recognized generalized tonic-clonic and myoclonic seizures alter the syndrome diagnosis and invalidate an absence-only treatment strategy. BMJ+2BMJAbsence seizures - Symptoms, diagnosis and treatment | BMJ Best PracticePubMedJuvenile Absence Epilepsy - StatPearls - NCBI Bookshelfnice org ukEpilepsies in children, young people and adults

Use repeat EEG when clinical events persist, the seizure phenotype changes, or treatment response is uncertain. For childhood absence epilepsy, continued generalized spike-wave activity during a habitual event supports ongoing absence seizures; in juvenile absence epilepsy and juvenile myoclonic epilepsy, faster spike-wave or polyspike-wave patterns can clarify the syndrome branch. BMJ+2BMJAbsence seizures - Symptoms, diagnosis and treatment | BMJ Best PracticeWolters KluwerOutcome of Absence Epilepsy With Onset at 8-11... : Journal of Child NeurologyPubMedJuvenile Absence Epilepsy - StatPearls - NCBI Bookshelf

Counsel families that childhood absence epilepsy often remits by adulthood, but avoid presenting remission as assured. Factors associated with failure to remit include cognitive difficulties at diagnosis, absence status before or during antiseizure therapy, later generalized tonic-clonic or myoclonic seizures, abnormal initial EEG background, and a first-degree family history of generalized seizures. These findings justify more cautious long-term surveillance and repeat syndrome assessment. BMJ+1BMJAbsence seizures - Symptoms, diagnosis and treatment | BMJ Best PracticeNeurologyLong-term prognosis of typical childhood absence epilepsy