Clinical scenario: Seizures | Developmental regression | EEG abnormality
A 4-year-old boy is referred to the epilepsy clinic because of frequent daily seizures and developmental regression. His parents report that seizures started at 2 years of age and include episodes of sudden falls, brief stiffening of the body, and periods of unresponsiveness.
His developmental assessment shows cognitive impairment. He is currently receiving two antiseizure medications but continues to have frequent seizures.
EEG demonstrates:
- Generalized slow spike-and-wave discharges at 1.5–2.5 Hz
- Paroxysmal fast activity during sleep
MRI brain reveals bilateral cerebral atrophy but no focal structural lesion.
Which of the following is the most likely diagnosis?
A. Childhood absence epilepsy
B. Juvenile myoclonic epilepsy
C. Lennox–Gastaut syndrome
D. Dravet syndrome
E. Benign epilepsy with centrotemporal spikes
Correct answer & Explanation:
Correct Answer:
C. Lennox–Gastaut syndrome
Explanation
This child has Lennox–Gastaut syndrome (LGS), a severe developmental and epileptic encephalopathy characterized by:
Diagnostic features:
- Onset in early childhood
- Usually between 1–8 years
- Multiple seizure types
- Atonic seizures → sudden falls (“drop attacks”)
- Tonic seizures → especially during sleep
- Atypical absence seizures
- Cognitive impairment/developmental delay
- Characteristic EEG
- Slow (<3 Hz) generalized spike-and-wave complexes
- Generalized paroxysmal fast activity (GPFA) during sleep (highly suggestive)
Why the other options are incorrect
A. Childhood absence epilepsy
- Normal development
- Brief staring episodes only
- EEG: regular 3-Hz spike-and-wave
- Does not cause drop attacks or developmental regression
B. Juvenile myoclonic epilepsy
- Usually adolescent onset
- Morning myoclonic jerks
- Normal cognition
- EEG: generalized polyspike-wave
C. Lennox–Gastaut syndrome – Correct
- Early childhood onset
- Multiple drug-resistant seizure types
- Cognitive impairment
- Slow spike-wave EEG
D. Dravet syndrome
- Usually begins in infancy with prolonged febrile seizures
- Later multiple seizure types and developmental impairment
- Often associated with SCN1A mutation
E. Benign epilepsy with centrotemporal spikes
- Focal seizures involving face/throat
- Normal cognition
- Centrotemporal spikes on EEG
Learning Point
Lennox–Gastaut syndrome =
- Childhood onset epilepsy
- Multiple seizure types (especially tonic + atonic seizures)
- Drug-resistant epilepsy
- Intellectual disability
- EEG: slow spike-wave (<3 Hz) + paroxysmal fast activity
Treatment options include:
- Valproate
- Clobazam
- Lamotrigine
- Rufinamide
- Cannabidiol (where available)
- Ketogenic diet
- Vagus nerve stimulation
- Corpus callosotomy for severe drop attacks
