Prevalence
~5% to 10% of children with seizures.

Incidence
~2.8/10,000 live births.

Age at onset
~1 to 7 years; peak at 3 to 5 years.

Sex
Males (60%) slightly predominate.

Neurological and mental state
Motor, cognitive, and behavioral abnormalities in ~60% prior to seizure onset.

Etiology
Extensive and diverse. Often severe brain disorders and malformations of cortical development (70%). 1/3 are idiopathic or probably symptomatic cases.

Clinical manifestations
Clusters of multiform seizures and mental retardation. Tonic seizures, atonic seizures, and atypical absences in this order of prevalence are the characteristic seizures. Falls, often traumatic, are common.

Non-convulsive status epilepticus of atypical absences, tonic and atonic seizures, and myoclonic jerks occur in half of the patients.

Seizure-precipitating factors
Sleep and inactivity.

Timing
Tonic seizures mainly during sleep.

Diagnostic procedures
Biochemical, hematological, metabolic, and other relevant screenings are rarely abnormal, depending on cause. Brain imaging is often abnormal.

Inter-ictal EEG
Background is usually slow, with paroxysms of fast rhythms and <2.5 Hz spike waves.

Ictal EEG
Variable according to seizure type. Tonic seizures = accelerating fast paroxysms (~20 Hz), atypical absences = <2.5 Hz spike-slow waves, myoclonic seizures = polyspikes, atonic seizures = spikes/polyspikes/slow spike waves and fast paroxysms. Flattening of all EEG activity alone or in combination with fast paroxysms is common.

Prognosis
Poor; 5% die, 80% to 90% continue having seizures in adult life. Nearly all (85% to 92%) have severe neurological and mental deficits. Normal development is exceptional.

Differential diagnosis
Non-epileptic conditions, other epileptic encephalopathies, EM-AS.

Management options*
Complete seizure control is highly unlikely. Valproate (all seizures), clonazepam (myoclonic), and phenytoin (tonic) are used. Lamotrigine, levetiracetam, or topiramate may be more effective than older medications. Felbamate is for specific cases.

Steroids are occasionally helpful.

Ketogenic diet is undergoing a mini-renaissance.

Vagal nerve stimulation is probably ineffective.

Resective neurosurgery for intractable cases with localized structural lesions can be considered.

Corpus callosotomy for intractable drop attacks can be considered.

In status epilepticus, intravenous benzodiazepines are used, sometimes with concomitant steroids, and with respiratory assistance. Intravenous diazepam and lorazepam may induce tonic seizures.

A multidisciplinary approach to the management of the patient and support for the family is needed.

*Expert opinion, please check FDA-approved indications and prescribing information

See also: http://professionals.epilepsy.com/page/syndromes_lennox.html

This page was adapted from:

The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos

Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007