Lennox-Gastaut Syndrome
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Direct answer
Lennox-Gastaut syndrome is a developmental and epileptic encephalopathy defined by the triad of multiple seizure types — tonic seizures, atypical absences and atonic drop attacks — an interictal EEG of slow generalised spike-and-wave at 1.5 to 2.5 Hz, and cognitive impairment, with onset typically between one and eight years and a peak around three to five. It is among the most treatment-resistant of the childhood epilepsies: valproate is the usual first-line broad-spectrum agent, rufinamide and clobazam have specific evidence for drop attacks, lamotrigine and topiramate help, and the wrong drugs — carbamazepine, phenytoin and oxcarbazepine — aggravate it. The ketogenic diet, vagus nerve stimulation and corpus callosotomy are the non-pharmacological pillars when drugs fail.
What you must remember
- Aetiology is dominated by structural causes — a substantial share evolve from earlier West syndrome, others follow meningitis, tuberous sclerosis, malformations or HIE, with genetic and unknown-cause remainders; Indian series over-represent post-infectious and perinatal causes.
- Tonic seizures, especially in sleep, are the signature type — axial stiffening that is easily missed without video-EEG; drop attacks from loss of tone cause the falls, injuries and helmet prescriptions.
- EEG: slow (1.5–2.5 Hz) generalised spike-and-wave on a slowed background, with bursts of fast rhythms in sleep; a sleep study is often needed to capture the tonic seizures.
- Drug ladder: valproate first line; lamotrigine added with caution of pharmacokinetic interaction; rufinamide specifically reduces drop attacks; clobazam (its active metabolite boosted by stiripentol) and topiramate as further options; levetiracetam widely used.
- Drugs to avoid: sodium-channel narrow-spectrum agents — carbamazepine, phenytoin, oxcarbazepine — which increase atonic and myoclonic seizures and can precipitate non-convulsive status.
- Non-pharmacological: ketogenic diet with real efficacy in this syndrome; vagus nerve stimulation for seizure frequency and quality of life; corpus callosotomy chiefly for injurious drop attacks; resective surgery only for the minority with a single resectable lesion.
- Status epilepticus in Lennox-Gastaut often takes an atypical absence or non-convulsive form — prolonged stupor with fluctuating responsiveness — and is under-recognised on general wards.
- The disease is lifelong: the exam expectation is management of seizures plus comorbidities — intellectual disability, behaviour problems, and the injury burden of falls.
How to work through refractory seizures
A five-year-old with global delay and daily falls: the consultation is really a seizure-inventory exercise. Begin with the inventory — tonic stiffening in sleep reported by parents who share a bed, a common and diagnostically decisive detail in Indian households; head-drop episodes at school; staring spells that interrupt meals; and periodic days of "dullness and slurring" that are non-convulsive status. Next the EEG with sleep capture, seeking the slow spike-and-wave and the nocturnal fast bursts. Then the drug audit, which usually reveals the exam's planted error — a child on carbamazepine whose drop attacks multiplied after its introduction; the single best intervention is withdrawal of the aggravating drug, before adding anything new. Build the regimen: valproate as the base (checking carnitine and liver profile, and avoiding it in pubescent girls where feasible), add lamotrigine slowly for its synergy, or rufinamide targeted at drop attacks. If injurious falls persist: callosotomy discussion, the ketogenic diet — with responder rates among the best in any epilepsy — and vagus nerve stimulation where cost permits, a genuine constraint in Indian practice. Finally, the life around seizures: a helmet, school supervision, a rescue benzodiazepine plan for clusters, and developmental referral for comorbidities that concern families more than seizure counts.
High-yield viva angles
The classic probe is the evolution question — a child with treated West syndrome returning with new drop attacks at four years is Lennox-Gastaut evolving, and candidates must connect the two syndromes through the shared structural aetiology. The second is the EEG frequency pair: 3 Hz belongs to absence epilepsy, 1.5 to 2.5 Hz to Lennox-Gastaut, and the question is asked as "slow spike-and-wave — name the syndrome". The third is the surgery nuance: callosotomy does not stop seizures, it stops the fall — a difference of concept that examiners use to test understanding rather than recall. Expect also the emergency angle: the drowsy, drooling Lennox-Gastaut child in the emergency department with no obvious convulsion is in non-convulsive status and needs an EEG and benzodiazepine trial, not a sedative.
Frequently asked questions
What is the EEG hallmark of Lennox-Gastaut syndrome?
Generalised slow spike-and-wave at 1.5 to 2.5 Hz on a slowed background, with bursts of fast rhythms during sleep.
Which drugs should be avoided in Lennox-Gastaut syndrome?
Carbamazepine, phenytoin and oxcarbazepine — narrow-spectrum sodium-channel blockers that aggravate atonic and myoclonic seizures.
Which medication has specific evidence for drop attacks?
Rufinamide, with clobazam as a well-supported adjunct for atonic seizures.
What is the role of corpus callosotomy?
It disconnects the hemispheres to abolish the fall of atonic and tonic seizures — reducing injuries rather than curing the epilepsy.
What form does status epilepticus take in Lennox-Gastaut?
Often non-convulsive or atypical absence status — prolonged fluctuating obtundation with subtle myoclonus, confirmed and treated with EEG guidance.