Epilepsy syndromes often have clear implications for etiology, treatment, and prognosis. Some syndromes are highly correlated with a single specific cause (eg, sodium voltage-gated alpha subunit 1 [SCN1A] mutation in Dravet syndrome), whereas others may be caused by a diverse group of genetic, structural, or metabolic etiologies, such as West syndrome or Lennox-Gastaut syndrome.
Increasingly, drug trials in pediatric epilepsy are focusing on efficacy in defined syndromes. Randomized controlled trials have documented the efficacy of hormonal treatment and vigabatrin in West syndrome (16); of add-on clobazam, rufinamide, topiramate, lamotrigine, felbamate, and cannabidiol in Lennox-Gastaut syndrome (17)(18); and of add-on stiripentol, cannabidiol, and fenfluramine in Dravet syndrome. (19)(20)(21)
Syndrome identification frequently informs prognosis regarding seizure control and remission as well as long-term neurocognitive function. For example, many early-onset syndromes, such as early myoclonic encephalopathy, West syndrome, Dravet syndrome, and Lennox-Gastaut syndrome, are associated with lifelong drug-resistant epilepsy, significant cognitive impairment, and increased mortality. (22)(23)(24) In others, such as myoclonic atonic epilepsy and epilepsy with continuous spike and wave during sleep, early seizure control can be challenging and cognitive concerns can initially be seen,
but long-term outcome can still be favorable in some patients. (25)(26) In the genetic generalized epilepsies, including childhood absence epilepsy, juvenile absence epilepsy, and juvenile myoclonic epilepsy, seizures are typically controlled. Cognitive outcomes are usually favorable;
However, higher rates of learning disability, executive dysfunction, and attention disorders, as well as poorer long-term psychosocial outcomes, may be seen. (27)(28) Finally, in the self-limited focal epilepsies of childhood, such as Panayiotopoulos syndrome or childhood epilepsy with centrotemporal spikes, patients may have subtle neurocognitive deficits during the active stage of epilepsy, but remission always occurs, and the long-term social prognosis is excellent. (29)(30)
For many epilepsy syndromes that are due to diverse etiologies, prognosis can be further clarified by defining underlying etiology. Many genetic, metabolic, or structural etiologies result in diffuse brain dysfunction with profound, premorbid intellectual disability that remains severe even if seizures are ultimately controlled.Syndrome identification is more common in children than adults with epilepsy, with a defined syndrome identified in approximately one-quarter of children. (4) Some syndromes may evolve over time into other syndromes. (31)(32)