ESSENTIALS OF DIAGNOSIS
About a quarter of childhood-onset epilepsy is age related, has characteristic clinical and electroencephalographic features, and has favorable prognoses when properly treated such as childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, early-onset childhood occipital epilepsy (Panayiotopoulos type), and benign epilepsy of centrotemporal spikes.
Some epilepsy syndromes in this age group present with worse manifestations and prognoses such as Lennox-Gastaut syndrome, Landau-Kleffner syndrome, and epileptic encephalopathy with continuous spike and wave during sleep.
Early recognition of epilepsy syndromes and their distinction from symptomatic epilepsies can lead to appropriate investigation, treatment, and prognostication.
This chapter covers common childhood-onset epilepsy syndromes. Other epilepsy diagnoses of various etiologies (eg, cortical dysplasia, tumor, inflammation, metabolic imbalance, mitochondrial encephalopathies) are not discussed in this chapter.
Childhood Absence Epilepsy
Childhood absence epilepsy (CAE) accounts for 10% to 17% of pediatric epilepsy.1
Age at onset is between 4 and 10 years with a peak at 5 to 7 years. Typical absence refers to a characteristic combination of clinical and electroencephalographic (EEG) manifestations. The semiology consists of abrupt transient impairments of consciousness manifested as behavioral pauses that can be accompanied by staring, automatisms (involuntary low-amplitude movement of hands or mouth), and myoclonia lasting from 4 to 20 seconds and occurs frequently throughout the day. Generalized tonic-clonic (GTC) seizures may occur.
The ictal and interictal discharges are characterized by generalized 3- to 4-Hz spike and slow wave complexes (Figure 21–1).
Video electroencephalography (EEG) recording. (A) A recording from a 9-year-old male with childhood absence epilepsy with generalized 3-Hz spike-wave complexes associated with an absence seizure. (B) A recording from a 16-year-old female with juvenile myoclonic epilepsy with generalized 4-Hz polyspike-wave complexes associated with myoclonia. (C) A recording from an 8-year-old male with benign epilepsy of centrotemporal spikes with spikes seen independently in the bilateral centrotemporal region.
Magnetic resonance imaging (MRI) of the brain shows no pathologic lesions.
Juvenile myoclonic epilepsy (JME) can present with absence seizures, but the predominant myoclonus and unique EEG features can differentiate the diagnoses. Eyelid myoclonia with absence seizures (Jeavons syndrome) presents with absence seizures associated with predominant eyelid myoclonia and retropulsion of the head. The ictal EEG shows generalized 3- to 6-Hz polyspike-wave complexes provoked by eye closure and photic stimulation.
Absence seizures can also ...