Treatment of Typical Absence Seizures and Related Epileptic Syndromes

Abstract

Typical absences are brief (seconds) generalised seizures of sudden onset and termination. They have 2 essential components: clinically, the impairment of consciousness (absence) and, generalised 3 to 4Hz spike/polyspike and slow wave discharges on electroencephalogram (EEG). They differ fundamentally from other seizures and are pharmacologically unique. Their clinical and EEG manifestations are syndrome-related. Impairment of consciousness may be severe, moderate, mild or inconspicuous. This is often associated with motor manifestations, automatisms and autonomic disturbances. Clonic, tonic and atonic components alone or in combination are motor symptoms; myoclonia, mainly of facial muscles, is the most common. The ictal EEG discharge may be consistently brief (2 to 5 seconds) or long (15 to 30 seconds), continuous or fragmented, with single or multiple spikes associated with the slow wave. The intradischarge frequency may be constant or may vary (2.5 to 5Hz). Typical absences are easily precipitated by hyperventilation in about 90% of untreated patients. They are usually spontaneous, but can be triggered by photic, pattern, video games stimuli, and mental or emotional factors. Typical absences usually start in childhood or adolescence. They occur in around 10 to 15% of adults with epilepsies, often combined with other generalised seizures. They may remit with age or be lifelong. Syndromic diagnosis is important for treatment strategies and prognosis. Absences may be severe and the only seizure type, as in childhood absence epilepsy. They may predominate in other syndromes or be mild and nonpredominant in syndromes such as juvenile myoclonic epilepsy where myoclonic jerks and generalised tonic clonic seizures are the main concern. Typical absence status epilepticus occurs in about 30% of patients and is more common in certain syndromes, e.g. idiopathic generalised epilepsy with perioral myoclonia or phantom absences. Typical absence seizures are often easy to diagnose and treat. Valproic acid, ethosuximide and lamotrigine, alone or in combination, are first-line therapy. Valproic acid controls absences in 75% of patients and also GTCS (70%) and myoclonic jerks (75%); however, it may be undesirable for some women. Similarly, lamotrigine may control absences and GTCS in possibly 50 to 60% of patients, but may worsen myoclonic jerks; skin rashes are common. Ethosuximide controls 70% of absences, but it is unsuitable as monotherapy if other generalised seizures coexist. A combination of any of these 3 drugs may be needed for resistant cases. Low dosages of lamotrigine added to valproic acid may have a dramatic beneficial effect. Clonazepam, particularly in absences with myoclonic components, and acetazolamide may be useful adjunctive drugs.

Antiepileptic drug treatment in children

“…ESM is still considered a first-line treatment for absence seizures, particularly for children with CAE with only this seizures type [34]. ESM may also be effective as adjunctive treatment for myoclonic seizures [35], drop attacks [36], and negative myoclonus [37].…”

Combined Effects of Feedforward Inhibition and Excitation in Thalamocortical Circuit on the Transitions of Epileptic Seizures

“…In the electroencephalogram (EEG), generalized absence seizures of epilepsy, mainly occurring in children and juvenile (Marten et al, 2009), are typically characterized by bilaterally highly synchronized 2–4 Hz spike and wave discharges (SWD) (Meeren et al, 2002; Sitnikova, 2010) with a brief impairment of consciousness (i.e., absence) (Panayiotopoulos, 2001; Sitnikova, 2010). In addition, absence epilepsy is the petit-mal onset and never accompanied by aura and convulsions.…”

Epilepsia Ausencias en el Hospital Nacional Cayetano Heredia (1998-2002).

“…Dos pacientes que salieron del estudio probablemente hayan tenido Ausencias Secundarias y no se describen sus características clínicas ni epidemiológicas. El porcentaje de ausencias con respecto al total de pacientes con epilepsia es ligeramente inferior al encontrado por Panayiotopoulos quien señala un porcentaje de 10% para las ausencias (11). Aquí, cabe considerar el factor asociado a la pobre referencia hacia nuestro hospital por el desconocimiento de la naturaleza y etiología de las manifestaciones clínicas de las ausencias.…”