Epilepsy Treatment

Treatment of epilepsy falls into four pillars: antiseizure medications (ASMs), surgical resection, neurostimulation devices, and general/lifestyle management. For refractory cases, status epilepticus requires its own emergency protocol.

1. Antiseizure Medications (ASMs)

General Principles

The goal of drug therapy is a seizure-free state with the fewest side effects. Key principles (Adams and Victor's Principles of Neurology, 12th Ed.):

Start with monotherapy at the lowest effective dose, titrating upward before switching or adding a second drug.
Prefer once or twice daily dosing for adherence.
~70% of patients achieve complete or near-complete seizure control with medications; ~20-25% achieve significant reduction.
~50% respond to the first ASM; another ~15% respond to a second as monotherapy. Remaining cases are considered treatment-resistant (drug-refractory epilepsy).
Polypharmacy success rates are low and generally not additive - each additional drug adds modest incremental benefit.
Drug choice depends on seizure/syndrome type, patient sex and age, comorbidities, drug interactions, teratogenicity risk, and tolerability.
Serum drug level monitoring is useful for phenytoin, carbamazepine, valproate, and phenobarbital.

Drug Choice by Seizure Type

Seizure Type	First-line Options	Notes
Focal (partial) seizures	Carbamazepine, oxcarbazepine, lamotrigine, levetiracetam, lacosamide	CBZ/OXC are enzyme inducers
Generalized tonic-clonic	Valproate, lamotrigine, levetiracetam, topiramate	Valproate highly effective but teratogenic
Absence seizures	Ethosuximide (first-line), valproate, lamotrigine	Ethosuximide: T-type Ca²⁺ channel blocker
Myoclonic seizures	Valproate, levetiracetam, clonazepam	Avoid carbamazepine (can worsen)
Tonic/atonic (Lennox-Gastaut)	Valproate, lamotrigine, topiramate, rufinamide, clobazam	Often polytherapy needed
Infantile spasms (West syndrome)	ACTH, vigabatrin, prednisolone	Vigabatrin: risk of retinal toxicity

Drug Reference Table (Major ASMs)

(Adams and Victor's, Table 15-5)

Drug	Mechanism	Indications	Key Limitations
Valproic acid	Multiple: GABA potentiation, NMDA inhibition, Na⁺ / T-type Ca²⁺ channel blockade	Focal, generalized, absence	Teratogenicity, hepatotoxicity (especially <2 yrs), weight gain, enzyme inhibitor
Phenytoin	Na⁺ channel blocker	Focal, generalized	Nonlinear kinetics, enzyme inducer, gingival hyperplasia, hirsutism, rash
Carbamazepine	Na⁺ channel blocker	Focal, generalized	Enzyme inducer, hyponatremia, risk of Stevens-Johnson (especially HLA-B*1502+)
Oxcarbazepine	Na⁺ channel blocker	Focal	Less marrow toxicity than CBZ; hyponatremia (3%), enzyme inducer
Lamotrigine	Na⁺ channel blocker	Focal, generalized	Rash (slow titration needed); enzyme inducer
Levetiracetam	SV2A synaptic vesicle modulation	Focal, generalized	Mood disturbance, irritability, psychosis
Brivaracetam	SV2A modulation	Focal, generalized	Fewer psychiatric side effects than levetiracetam
Topiramate	Multiple: GABA↑, AMPA↓, Na⁺/Ca²⁺ blockade	Focal, generalized	Cognitive impairment, nephrolithiasis, weight loss
Lacosamide	Na⁺ channel (slow inactivation)	Focal, generalized	Generally well tolerated
Zonisamide	Na⁺ / T-type Ca²⁺ blockade	Focal, generalized	Nephrolithiasis, cognitive impairment, weight loss
Ethosuximide	T-type Ca²⁺ channel blocker	Absence seizures	Insomnia, GI upset
Phenobarbital	GABA potentiation	Focal, generalized	Sedation, enzyme inducer, dependence
Gabapentin / Pregabalin	Ca²⁺ channel (α2δ subunit)	Focal, adjunctive	Pregabalin: weight gain; limited monotherapy evidence
Perampanel	AMPA receptor antagonist	Focal, generalized (adjunctive)	Aggression, dizziness
Vigabatrin	Irreversible GABA transaminase inhibitor	Infantile spasms; focal (adjunctive)	Irreversible visual field defects - requires monitoring
Clonazepam / Diazepam	GABA potentiation (BZD)	Adjunctive; acute rescue	Tolerance, sedation, dependence

2. When to Start Treatment

The MESS (Multicentre Trial for Early Epilepsy and Single Seizures) trial showed that treatment after a first unprovoked seizure reduces seizure recurrence at 6 months (18% vs 26%) and delays time to next seizure - but long-term survival and functional outcomes were similar between treated and untreated groups. Treatment decisions must therefore weigh:

Risk of recurrence (abnormal EEG, structural lesion, nocturnal seizures increase risk)
Driving/occupational implications
Patient preference and medication tolerability

3. Drug-Resistant Epilepsy

Drug resistance is defined as failure of two adequate, well-tolerated ASM trials (whether as monotherapy or combination). These patients (~30%) should be referred for epilepsy surgery evaluation promptly rather than subjected to years of failed medication trials.

4. Surgical Treatment

Resective Surgery

Best candidates: focal epilepsy with unilateral temporal lobe origin.
Temporal lobectomy or amygdalohippocampectomy: seizure freedom rates of ~58-70% at 1 year; >50% remain seizure-free at 10 years (compared to ~8% on medication alone in randomized trials).
Extratemporal neocortical resection: ~50% seizure-free outcomes.
Hemispherectomy: for hemispheric abnormalities (hemimegalencephaly, Rasmussen encephalitis, Sturge-Weber disease, large porencephalic cysts).
Corpus callosotomy: palliative; most effective for disabling atonic "drop attacks" in mixed-seizure syndromes (e.g., Lennox-Gastaut).

Presurgical Evaluation

Inpatient video-EEG monitoring to localize seizure focus
High-resolution MRI (higher field strength improves lesion detection)
Functional imaging: PET, SPECT, MEG (adjunctive)
Neuropsychological testing + Wada test (intracarotid amobarbital) or fMRI for language/memory lateralization
Invasive EEG if needed: Stereo-EEG (sEEG) via depth electrodes (less invasive, shorter hospital stay vs. subdural grids) or subdural electrode grids

5. Neurostimulation Devices

For patients who are not surgical candidates or whose seizure focus cannot be resected (Harrison's, 22nd Ed.):

Device	Mechanism	Notes
Vagus Nerve Stimulation (VNS)	Pacemaker implanted in chest wall; electrodes on left vagus nerve	~25% reduction in seizure frequency; hoarseness common; mechanism unclear
Responsive Neurostimulation (RNS)	Implanted cranial device detects and responds to epileptiform activity; closed-loop	~15% achieve seizure freedom; outcomes improve over time
Deep Brain Stimulation (DBS)	Stimulation of anterior thalamic nucleus (ANT)	Approved for refractory focal epilepsy; >50% seizure reduction in many patients

No head-to-head trials exist between these devices; device choice is individualized.

6. Status Epilepticus - Emergency Management

Generalized convulsive status epilepticus (GCSE) is a medical emergency: seizures >5 minutes (operational definition) require immediate treatment to prevent irreversible CNS injury, hyperthermia, and metabolic derangement.

Step-wise Protocol:

ABCs - airway, breathing, circulation; IV access; labs (glucose, electrolytes, AED levels, toxicology)
First-line (0-5 min): IV/IM benzodiazepine
- IV lorazepam 0.1 mg/kg (preferred)
- IM midazolam 10 mg (if no IV access - non-inferior to IV lorazepam per RAMPART trial)
- IV diazepam 0.15-0.2 mg/kg
Second-line (5-20 min if seizures persist): One of:
- IV fosphenytoin (20 mg PE/kg) or phenytoin
- IV levetiracetam (60 mg/kg, up to 4500 mg)
- IV valproate (40 mg/kg)
Third-line / Refractory SE (>30 min or failure of 2 agents):
- Intubation + continuous infusion of midazolam, propofol, or pentobarbital with EEG monitoring
Non-convulsive SE (NCSE): Treat similarly but with less urgency; portable EEG headbands can aid diagnosis at bedside.

7. Other Management Considerations

Seizure triggers: Identify and minimize sleep deprivation, alcohol, stress, photosensitivity, and drug/medication non-compliance.
Driving: Most jurisdictions require a seizure-free period (typically 6-12 months) before driving.
Women of childbearing age: Folate supplementation (5 mg/day) before and during pregnancy; avoid valproate where possible (highest teratogenic risk); enzyme-inducing ASMs reduce hormonal contraceptive efficacy.
Ketogenic diet: High-fat, low-carbohydrate diet - effective adjunct, especially in children with drug-resistant epilepsy or specific metabolic epilepsies (GLUT-1 deficiency, pyruvate dehydrogenase deficiency).
Comorbidities: Depression, anxiety, cognitive dysfunction, and SUDEP (Sudden Unexpected Death in Epilepsy) risk should be actively addressed. SUDEP risk is highest with uncontrolled nocturnal tonic-clonic seizures.
Withdrawal of ASMs: After 2-5 years of seizure freedom, gradual withdrawal may be considered; relapse risk varies by syndrome and EEG findings.

Summary

Treatment modality	When to use
ASM monotherapy	First-line for all epilepsy
ASM polytherapy	After 1-2 monotherapy failures
Surgery evaluation	After 2 adequate ASM failures (drug-resistant epilepsy)
Resective surgery	Focal epilepsy with identifiable lesion/focus
Neurostimulation (VNS/RNS/DBS)	Non-resectable focal or generalized refractory epilepsy
Ketogenic diet	Children; GLUT-1 deficiency; adjunct in drug-resistant cases
Emergency BZD + second-line IV ASM	Status epilepticus

Sources: Adams and Victor's Principles of Neurology, 12th Ed. - Harrison's Principles of Internal Medicine, 22nd Ed. (2025)

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