Epilepsy

The classification of epilepsy has been updated by the International League Against Epilepsy (ILAE) in 2025. The new classification system includes: Four main seizure classes: Focal, Generalized, Unknown (whether focal or generalized), and Unclassified. Clinically, you first decide if the seizure is focal/generalized/unknown and whether consciousness is impaired or preserved, then layer on descriptors (e.g. focal impaired consciousness seizure with automatisms and right arm clonic movements), giving a structure that’s more intuitive for ward notes, MDTs and surgical work-up while still mapping cleanly to the formal ILAE scheme

Focal vs Generalised

Classification

📌 Teaching Summary

• Define the seizure onset, then classify the broader epilepsy type/syndrome.
• Never start carbamazepine/oxcarbazepine in suspected genetic generalised epilepsy (e.g. JME, CAE) – it can worsen seizures.
• Always consider aetiology — structural, metabolic and immune causes are commonly missed.
• This layered classification guides both prognosis and treatment selection.

⚡ Epilepsy = a chronic brain disorder causing a persistent propensity to unprovoked seizures.
Prevalence ~0.5–1%; bimodal peaks (👶 childhood, 🧓 older adults).
🎯 Core aims: correct diagnosis → precise classification → personalised therapy with the fewest adverse effects, while optimising learning, work, driving, pregnancy, and quality of life.

🧠 Seizures & Epilepsy — Key Concepts

• Provoked (acute symptomatic): within 7 days of brain insult or metabolic derangement (Na⁺, glucose, EtOH withdrawal, stroke, ICH, neurosurgery). Treat the cause → not epilepsy.
• Unprovoked seizures → consider epilepsy. Epilepsy can be diagnosed after 1 unprovoked seizure if the 10-yr recurrence risk ≥60% (e.g. epileptiform EEG or a clear concordant structural lesion).
• ILAE Classification: focal onset (aware/impaired), generalised onset (absence, myoclonic, tonic–clonic, etc.), or unknown onset.

🧩 Aetiology by Age

• 👶 Children: genetic generalised epilepsies (CAE, JME), perinatal injury, cortical malformations, metabolic disorders, neurocutaneous syndromes (TSC, NF1), infections.
• 🧑 Adults: stroke, tumour, traumatic brain injury, CNS infection (HSV, neurocysticercosis globally), autoimmune encephalitis, alcohol/withdrawal, sleep loss, meds (tramadol, bupropion), electrolyte/glucose disorders.
• 🧓 Older adults: cerebrovascular disease, neurodegeneration, polypharmacy, brain tumours.

🔎 First Seizure Work-up (Adults & Children)

• 🏷️ History + witness account: aura, head/eye version, automatisms, cyanosis, lateral tongue bite, injuries, post-ictal phase, triggers.
• 🩺 Exam: neuro, skin (neurocutaneous), infection signs.
• 🧪 Bloods: glucose, U&E, Ca²⁺/Mg²⁺, LFTs, FBC ± tox screen; pregnancy test where relevant.
• 🧲 MRI epilepsy protocol for focal seizures, abnormal exam, adult onset, drug resistance.
• 📈 EEG (ideally within days). If nondiagnostic: sleep-deprived/ambulatory EEG. Video-EEG for frequent atypical events to differentiate PNES/syncope.
• 👶 Consider metabolic/genetic panels for early-onset, refractory, or syndromic features.

🧭 When to Start Anti-Seizure Medication (ASM)?

• ≥2 unprovoked seizures, or after 1 if high risk (epileptiform EEG, structural lesion, persistent deficit).
• Shared decision-making: recurrence risk, adverse effects, contraception, driving, job safety.
• Monotherapy first; “start low, go slow”; titrate to seizure freedom or max tolerated dose → then switch/adjunct.

💊 First-Line ASMs by Syndrome/Type (Adults & Children)

📏 Practical Dosing & Titration (Adults unless stated)

• Levetiracetam 👉 start 250–500 mg BD; ↑ by 250–500 mg BD q1–2 wk; usual 1–3 g/day. (Paeds: 10–20 mg/kg/day BD → 30–60 mg/kg/day). ⚠️ Irritability/low mood—consider pyridoxine 50 mg/day if troublesome, and switch if behaviour remains significantly impaired.
• Lamotrigine 👉 start 25 mg OD for 2 wk → 50 mg OD for 2 wk → then ↑ by 50 mg every 1–2 wk to 100–200 mg BD.
  • With valproate: start 12.5 mg OD (or 25 mg alternate days), titrate very slowly.
  • With enzyme inducers (CBZ, PHT): faster titration acceptable. ⚠️ Rash/SJS—stop if any mucocutaneous blistering.
• Carbamazepine 👉 100–200 mg BD → ↑ by 100–200 mg BD weekly; usual 800–1200 mg/day (MR preferred). Monitor Na⁺ (SIADH). HLA-B*1502 (SE Asian ancestry) risk SJS.
• Lacosamide 👉 50 mg BD → ↑ 50 mg BD weekly to 100–200 mg BD. ⚠️ PR prolongation—baseline ECG if cardiac history.
• Valproate* 👉 250–500 mg BD → usual 1–2 g/day (target clinical). Weight gain, tremor, hair changes, thrombocytopenia. Teratogenic/ND risk—use only under PPP in females of childbearing potential.
• Topiramate 👉 25 mg ON → ↑ by 25–50 mg weekly to 50–100 mg BD. ⚠️ Cognitive slowing, paraesthesia, stones, weight loss; teratogenic; ↓ OCP efficacy. Use cautiously in students or in highly cognitively demanding jobs.
• Ethosuximide 👉 250 mg BD → titrate to 500 mg–1 g/day (Paeds: 10–20 mg/kg/day). GI upset common.
• Clobazam 👉 10 mg ON → 10 mg BD; max 40 mg/day. Sedation, tolerance—best as adjunct/intermittent for clusters.

🧪 Monitoring, Interactions & Side-effects

🧡 Lifestyle, Safety & Self-management

• 😴 Sleep hygiene, limit alcohol, regular meds, stress strategies, avoid known triggers (photosensitivity: use screen filters).
• 🏊 Safety: showers not baths, supervise swimming, avoid heights/open flames/lone ladder work.
• 📟 Rescue plan for clusters: buccal midazolam 10 mg (0.5 mg/kg up to 10 mg in children) or rectal diazepam 10–20 mg at home; call EMS if seizure >5 min or repeats without recovery.
• 🪫 SUDEP: risk higher with frequent nocturnal GTCS, non-adherence and polytherapy; risk is lowest with seizure control, adherence, and nocturnal supervision/alarms where appropriate.
• 🚘 Driving (UK DVLA): typically no driving after a first unprovoked seizure. For Group 1, a seizure-free interval of at least 6–12 months is usually required before resuming — always check current DVLA guidance and licence type.

🤰 Epilepsy, Contraception & Pregnancy

• 🍼 Pre-conception: aim for seizure freedom on the fewest, safest ASMs. Folic acid 5 mg/day from ≥3 months pre-conception to 12 wks gestation.
• ❌ Valproate: avoid in women/girls unless no alternative and PPP in place (informed consent, effective contraception, annual specialist review).
• ✅ Preferred in pregnancy: Lamotrigine, Levetiracetam (monitor levels; lamotrigine clearance rises—dose often needs ↑ each trimester, ↓ postpartum).
• 💊 Enzyme inducers (CBZ, PHT, PB, topiramate at higher doses) ↓ hormonal contraceptive efficacy → consider copper/levonorgestrel IUD, depot medroxyprogesterone, or higher-dose/continuous OCP with backup.
• 🤰 Peripartum seizure risk reflects pre-pregnancy control — pregnancy itself is not protective; maintain ASM adherence around labour.
• 🍼 Breastfeeding generally safe (monitor infant for sedation/poor feeding).
• 🟨 Vitamin K: follow local policy if on enzyme-inducing ASMs (late pregnancy maternal and neonatal protocols).

👶 Paediatric Highlights

• Febrile seizures: brief, generalised, 6–60 months; usually no ASMs. Red flags: focal/prolonged (>15 min) or recurrent same illness → assess/admit.
• Childhood Absence Epilepsy: 3-Hz spike-wave; first line ethosuximide.
• Infantile spasms (West): salaam spasms, regression, hypsarrhythmia → emergency; ACTH/steroids or vigabatrin (esp. TSC) with urgent specialist care. Loss of previously acquired skills is as important as the spasms themselves.
• Ketogenic diet effective adjunct in refractory childhood epilepsies (dietitian-led).

🆘 Status Epilepticus (Convulsive) — Adult Emergency Algorithm

Definition: ≥5 min of generalised tonic–clonic activity or recurrent seizures without recovery.
Priorities: ABCDE, oxygenation, stop the seizure, treat the cause, prevent complications.

1. ⏱️ 0–5 min: Airway, high-flow O₂, glucose check (treat if low), IV access, monitor (ECG, BP, SpO₂), bloods (U&E, Ca²⁺/Mg²⁺, LFT, FBC, toxins, ASM levels if relevant).
2. 💉 1st line benzodiazepine (give now):
   • IV lorazepam 4 mg slow IV.
   • If no IV: buccal midazolam 10 mg (0.5 mg/kg up to 10 mg in children) or rectal diazepam 10–20 mg.
   • May repeat once after 10 min if still seizing.
3. 🧪 2nd line loading (choose one, over ~10–20 min):
   • Levetiracetam 40–60 mg/kg (max 4.5 g)
   • Valproate 40 mg/kg (max 3 g) — avoid if pregnant/unknown pregnancy risk
   • Phenytoin 20 mg/kg (or fosphenytoin PE 20 mg/kg) with cardiac monitoring
   Prefer levetiracetam or valproate where suitable; reserve phenytoin/fosphenytoin for when these are inappropriate or unavailable.
4. 🏥 Refractory (>30–40 min): ICU, intubation, continuous EEG; anaesthetic infusion (propofol, midazolam, thiopental) and cause-directed therapy (meningitis/encephalitis cover if suspected). Always consider non-convulsive status at this stage.

🧪 Key Differentials

• Convulsive syncope, PNES, migraine/hemiplegic migraine, parasomnias, TIA, movement disorders, hypoglycaemia/electrolyte disturbance, cataplexy.

📅 Follow-up & Escalation

• Review seizure diary, adherence, adverse effects; titrate doses; consider switch/adjunct after 2–3 adequate trials.
• Consider drug-resistant epilepsy (failure of two appropriate ASMs) → refer to specialist centre for surgical evaluation, VNS/RNS, dietary therapies.
• Bone health (vitamin D/calcium) with enzyme-inducing ASMs; screen mood/cognition routinely.

📝 High-Yield Exam Pearls

• Classify first → ASM follows the classification.
• Lamotrigine: titrate slowly; stop for rash. Levels drop in pregnancy → plan proactive dose adjustments.
• Valproate: excellent efficacy for generalised epilepsies but avoid in females of childbearing potential unless PPP criteria met.
• Status ladder: BZD → Levetiracetam/Valproate/Phenytoin → ICU.
• Always think syncope/PNES in unclear cases → video-EEG if available.