Makindo Medical Notes

Related Subjects: |Status Epilepticus (Epilepsy) |Coma management |Lorazepam |Phenytoin |Levetiracetam |Epilepsy - General Management |First Seizure |Epilepsy in Pregnancy |Febrile seizures

🧠 Introduction

Lennox-Gastaut Syndrome (LGS) is a rare, severe childhood epilepsy syndrome (≈2–5% of paediatric epilepsies). It typically presents between 3–5 years of age with multiple seizure types, cognitive impairment, and a characteristic slow spike–wave EEG. Seizures are often drug-resistant, making LGS one of the most challenging epileptic syndromes to manage.

🔎 Etiology

• Identifiable in ~70% of cases; idiopathic in others.
• Common causes:
  • Structural: cortical dysplasia, malformations, perinatal hypoxia-ischaemia.
  • Genetic: e.g. mutations in SCN1A, CHD2, or in tuberous sclerosis.
  • Infective: encephalitis, meningitis.
  • Metabolic: mitochondrial / inborn errors of metabolism.
  • Acquired: severe head trauma.

📌 Associations

• Intellectual disability (often progressive).
• Behavioural problems: hyperactivity, aggression, autistic traits.
• Coexisting syndromes e.g. autism spectrum disorder, developmental delay.

⚡ Clinical Features

• Multiple seizure types:
  • Atonic “drop attacks”: sudden falls, high injury risk.
  • Tonic seizures: often during sleep, cause stiffening.
  • Atypical absences: brief lapses in awareness.
  • Myoclonic jerks: brief shock-like twitches.
  • GTCS: usually later in childhood.
• Non-convulsive status epilepticus is common (confusional state, altered awareness).
• Slow intellectual development or regression of skills.

🧪 Investigations

• EEG:
  • Generalised slow <3 Hz spike–wave discharges (diagnostic).
  • Paroxysmal fast activity during sleep.
• MRI: to look for cortical malformations, perinatal insults, tumours.
• Genetic testing: increasingly useful in diagnosis.
• Metabolic screening: if clinically suspected.

💊 Management

• Antiepileptic drugs (AEDs):
  • First-line: Sodium Valproate (avoid in fertile females if possible).
  • Adjuncts: Lamotrigine, Topiramate, Clobazam, Rufinamide.
  • Second-line/adjuncts: Felbamate (rare, high toxicity), Cannabidiol (licensed for LGS).
• Ketogenic diet: high-fat, low-carb → can reduce seizure frequency (requires specialist supervision).
• Vagus Nerve Stimulation (VNS): useful in refractory cases.
• Surgery:
  • Corpus callosotomy: reduces drop attacks.
  • Focal resection: if single lesion identified.
• Supportive: special education, behavioural therapy, family support.

📉 Prognosis

• Generally poor seizure control (often drug-resistant).
• Progressive cognitive and behavioural impairment in most cases.
• Frequent injuries from falls due to atonic seizures.
• Increased mortality: including SUDEP (sudden unexpected death in epilepsy).

✅ Key Teaching Points

• LGS = triad of multiple seizure types, developmental delay, and slow spike–wave EEG.
• Most patients need combination AED therapy.
• Atonic “drop attacks” are highly disabling and injury-prone → corpus callosotomy can be transformative.
• Always consider SUDEP counselling and family support services.