Prevalence
~6% of epilepsies that start before the age of 3 years.

Incidence
~1/30,000 live births.

Age at onset
First year of life at a peak age of 5 months.

Sex
Males (66%) predominate.

Neurological and mental state
Normal prior to the onset of seizures.

Etiology
Mostly genetically determined with mutations in sodium channel genes. It is the most severe phenotype of autosomal dominant epilepsy with FS+.

Clinical manifestations
Tetrad of seizures: (1) early infantile febrile clonic convulsions; (2) myoclonic jerks; (3) atypical absences; and (4) complex focal seizures.

Three periods of evolution: (1) relatively mild with clonic seizures usually occurring during febrile illnesses; (2) relentlessly aggressive period with numerous myoclonic, atypical absence and complex focal seizures and status epilepticus lasting for hours or days; and (3) static period where seizures improve but serious and residual mental and neurological abnormalities remain forever.

Timing
On arousal and during alert states; uncommon in sleep (3%).

Seizure-precipitating factors
Febrile illnesses raised body temperature, hot baths, photic and pattern stimulation, movements, and eye closure.

Diagnostic procedures
MRI shows mild and non-specific abnormalities. Metabolic tests and skin and muscle biopsies are normal; mitochondrial cytopathy is exceptional.

Inter-ictal EEG
Background progressively becomes slow, with frequent and severe generalized polyspikes-slow waves and 2 Hz spike-slow waves. Multifocal abnormalities of spikes and slow waves are common.

Ictal EEG
Varies according to the type of seizure.

Prognosis
Seizure deterioration, mental and neurological decline is relentless and often fatal.

Differential diagnosis
Febrile convulsions, Lennox-Gastaut syndrome, EM-AS, benign myoclonic epilepsy in infancy, progressive myoclonic epilepsies.

Management options*
Seizures are intractable to any AED. Carbamazepine, phenytoin and lamotrigine are contraindicated.

Early treatment of infectious diseases and hyperthermia (triggering factors of status epilepticus) are mandatory.

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