LENNOX-GASTAUT SYNDROME (LGS)

	Mandatory	Alerts
Seizures	Tonic seizures and ≥1 of: Atypical absences Atonic seizures Myoclonic seizures Focal impaired awareness seizures Generalized tonic-clonic seizures Epileptic spasms Nonconvulsive status epilepticus
EEG	Generalized slow (<2.5Hz) spike-wave Generalized paroxysmal fast activity in sleep	Photoparoxysmal response at low flash frequency (consider CLN2)
Age at onset	<18 years	>8 years
Course of illness	Drug resistant epilepsy Intellectual impairment
Are MRI or ictal EEG required for diagnosis? An MRI is not required for diagnosis but is usually performed to look for a cause An ictal EEG is not required, however should be strongly considered where alerts are present or if epilepsy with myoclonic atonic seizures is a differential
Syndrome without laboratory confirmation: in resource-limited regions, this syndrome cannot be diagnosed without EEG showing at least generalised slow spike-wave in wakefulness.

NOTE Alert criteria are absent in the vast majority of patients with the syndrome, but rarely can be seen. Their presence should result in caution in diagnosing the syndrome and consideration of other conditions