Epilepsy: ILAE 2017 Classification, Anticonvulsant Selection, and Status Epilepticus

1. Definitions (ILAE 2014)

Epilepsy is a condition characterized by any of the following criteria:

• ≥ 2 unprovoked (or reflex) seizures occurring > 24 hours apart;
• 1 unprovoked seizure + a recurrence risk of ≥ 60% over the next 10 years;
• diagnosis of an epilepsy syndrome.

Epilepsy is considered resolved if the patient has been seizure-free for the last 10 years, with at least the last 5 years off antiseizure medications.

2. Seizure Classification (ILAE 2017)

3. Etiology

• Structural — stroke, tumor, trauma, cortical dysplasia, mesial temporal sclerosis.
• Genetic — childhood absence epilepsy, juvenile myoclonic epilepsy (Janz syndrome), Dravet syndrome (SCN1A).
• Infectious — neurocysticercosis, herpes simplex encephalitis, meningitis.
• Metabolic — hypoglycemia, hypocalcemia, uremia.
• Immune — autoimmune encephalitis (anti-NMDAR, anti-LGI1).
• Unknown — about 30%.

4. Clinical presentation of typical forms

Generalized tonic-clonic

• Aura (not always), loss of consciousness.
• Tonic phase (10–20 sec) — sharp rigidity, vocalization, falling.
• Clonic phase (1–2 min) — generalized convulsions.
• Postictal phase — confusion, sleep, headache, myalgia.
• Tongue biting (lateral!), involuntary urination.

Absence seizures

• Sudden "staring spell" for 5–15 sec, speech arrest, blank gaze.
• EEG — generalized 3 Hz spike-wave complexes.
• Onset at 4–10 years; provoked by hyperventilation.

Focal impaired awareness seizures (formerly "complex partial")

• Aura (fear, déjà vu, epigastric rising sensation).
• Automatisms (lip smacking, manual fumbling, "clothing manipulation" automatism).
• Postictal amnesia and confusion.

Myoclonic

• Brief lightning-fast jerks, typically in the morning.
• Juvenile myoclonic epilepsy — onset at 12–18 years, provoked by sleep deprivation.

5. Diagnostics

• EEG — routine, sleep-deprived, long-term video-EEG monitoring. A negative result does not rule out epilepsy.
• Brain MRI using an epilepsy protocol at 1.5–3 T — to look for hippocampal sclerosis, cortical dysplasias, tumors.
• CT — urgently upon the first seizure in the emergency department.
• Blood tests: glycemia, electrolytes, Ca, Mg, Na, renal and hepatic function.
• Lumbar puncture — if infection/inflammation is suspected.
• Specific antibodies if autoimmune encephalitis is suspected.

6. Choice of antiseizure medication

7. Principles of pharmacotherapy

• Start with monotherapy, slow titration — minimum adverse effects.
• If the 1st drug fails, switch to the 2nd with a 2-week overlap.
• Polytherapy — indicated if ≥ 2 monotherapy regimens fail.
• Therapeutic drug monitoring: phenytoin, carbamazepine, valproate, lamotrigine.
• Considerations in women of childbearing potential: valproate is teratogenic (NTD), must not be used without an alternative; topiramate — reduces fetal birth weight, cleft palate; lamotrigine and levetiracetam — preferred.
• Discontinuation of therapy — if seizure-free for ≥ 2 years, following consultation with an epileptologist and a normal EEG.

8. Drug-resistant epilepsy

ILAE definition: failure of adequate trials of two tolerated, appropriately chosen and adequately dosed antiepileptic drug schedules to achieve sustained seizure freedom.

• ≈ 30% of patients are pharmacoresistant.
• Surgery: resection of the epileptogenic zone (hippocampal sclerosis — 70% success rate), functional hemispherotomy, callosotomy.
• Neuromodulation: vagus nerve stimulation (VNS), deep brain stimulation (DBS), responsive neurostimulation (RNS).
• Ketogenic diet — effective in children with Dravet and Lennox-Gastaut syndromes.

9. Status epilepticus

Definition

Convulsive SE: seizure > 5 min or a series without recovery of consciousness. Non-convulsive SE — requires video-EEG.

Relief algorithm

1. 0–5 min: ABC, oxygen, IV access, glucometer, baseline blood chemistry. If IV access is unavailable — diazepam rectally 0.2–0.5 mg/kg or midazolam buccally/intranasally.
2. 5–20 min: lorazepam 0.1 mg/kg IV (or diazepam 0.15–0.2 mg/kg). Can be repeated after 5 min.
3. 20–40 min (established SE): levetiracetam 60 mg/kg (max 4500 mg) or valproate 40 mg/kg (max 3000 mg) or phenytoin 20 mg/kg. All IV.
4. 40–60 min (refractory SE): intubation + anesthetic (thiopental, propofol, midazolam IV infusion) with EEG monitoring targeting burst suppression for 24 h.
5. Super-refractory: ketamine, hypothermia, immunotherapy for autoimmune etiology.

10. First aid during a seizure (for laypersons)

• Do not restrain, do not place objects in the mouth.
• Remove hazardous objects, place something soft under the head.
• Turn onto the side after the seizure.
• Time the seizure, describe the phases.
• Call an ambulance if seizure > 5 min, series of seizures, pregnancy, trauma, first-time seizure.

11. FAQ

Can I drive a car?
In Russia, driving is prohibited with epilepsy; license reinstatement is possible after 1 year of seizure freedom and a medical board decision. Category A has stricter requirements.

Is valproate dangerous for girls?
Yes: risk of congenital malformations 10% and neurodevelopmental disorders. EMA restricts its use in women of childbearing potential without a Pregnancy Prevention Programme.

What is SUDEP?
Sudden unexpected death in epilepsy. Risk factors: frequent GTCS, nocturnal seizures, drug resistance. Seizure control is the main prevention.

How to distinguish a seizure from syncope?
Syncope features pallor, diaphoresis, absence of postictal confusion, rapid recovery, no tongue biting or urinary incontinence (though myoclonic jerks may occur due to anoxia).

Can I play sports?
Yes, except for high-risk activities (scuba diving, solo rock climbing). Swimming is allowed only under supervision. Better seizure control leads to fewer restrictions.

See also: Stroke · Multiple sclerosis · Cranial nerves · Antidepressants · Neurology index