Lennox Gastaut Syndrome

Background

• Severe seizures in childhood
• Presentation before eight years of age, most commonly between three and five years of age
• Many cases evolve into Lennox Gastaut from other epilepsy syndromes, particularly West Syndrome (Infantile Spasm)

Clinics

• Mixture of seizure types
  • Tonic
  • Tonic-clonic
  • Atonic (drop attacks)
  • Myoclonic
  • atypical absences
• Brief tonic seizures of seconds to 1 minute.
• The seizures can cause falls.
• Eyelid retraction, staring, mydriasis, and apnea are commonly associated
• The seizures are frequent
• Mental retardation before seizure onset in 20-60%

EEG

• Spike-and-wave superimposed on an abnormal, slow background.
• The Spike slow wave complex and Sharp wave slow wave complex are generalized at a frequency of 1.5 to 2.5 Hz (slow)
• Transient and shifting asymmetries are frequent
• Non-REM sleep increases the discharges. In REM sleep the discharges decreases.
• Hyperventilation or photic stimulation does not trigger the discharges.

Ictal EEG

• Tonic seizure: typically fast rhythmic discarges of 10 – 20 Hz, increasing in amplitude.
• Myoclonic seizures: bursts of arrhythmic, multiple spike-wave or irregular spike-wave activity
• Atypical absence seizures: Slow (<2.5 Hz) and often asymmetric and irregular spike-and-wave activity

Treatment

• No drug is highly effective
• Valproic acid, lamotrigine, topiramate, rufinamide, felbamate, and clobazam can be effective
• Carbamazepine can worsen the drop attacks