Epilepsy: Causes, Types and Treatment

Epilepsy: Causes, Types and Treatment

Epilepsy is one of the most common serious neurological conditions worldwide, affecting approximately 50 million people — about 1% of the global population. It is defined as a tendency to have recurrent, unprovoked seizures — sudden, transient episodes of abnormal electrical activity in the brain that cause changes in movement, sensation, behaviour, awareness, or consciousness.

A single seizure does not always mean epilepsy. Diagnosis may follow two unprovoked or reflex seizures more than 24 hours apart, one such seizure with an estimated recurrence probability of at least 60% over the next 10 years, or identification of an epilepsy syndrome.

Epilepsy is highly treatable — approximately 70% of people with epilepsy achieve good seizure control with antiseizure medication. For the 30% who do not respond adequately to medication, surgical options may offer significant benefit or even cure.

How Seizures Occur

The brain functions through the coordinated electrical activity of billions of neurons. A seizure occurs when a population of neurons fires abnormally, synchronously, and excessively, disrupting normal brain function.

Focal (partial) seizures originate from a localised region of one cerebral hemisphere — the seizure focus. Symptoms depend on the function of the brain area involved. Focal seizures may remain localised or spread to involve the entire brain (secondary generalisation).

Generalised seizures arise within and rapidly engage networks distributed across both sides of the brain. This classification does not by itself establish diffuse underlying brain pathology.

Causes and Classification

By Aetiology

Structural: a visible lesion causing seizures — hippocampal sclerosis (a structural abnormality associated with mesial temporal lobe epilepsy), brain tumours, cortical dysplasia (malformations of brain development), stroke, traumatic brain injury, post-infectious encephalitis.

Genetic: epilepsies caused by gene mutations affecting ion channels, receptors, or membrane excitability. Examples: Dravet syndrome (SCN1A mutation), KCNQ2, PRRT2. Childhood absence epilepsy and juvenile myoclonic epilepsy have strong genetic components.

Infectious: encephalitis caused by infection (for example, viral or bacterial), neurocysticercosis (the most common cause of acquired epilepsy in the developing world — caused by tapeworm larvae — Taenia solium — in the brain).

Metabolic: epilepsy can result from a defined metabolic disorder, such as glucose transporter type 1 deficiency, pyridoxine-dependent epilepsy or some mitochondrial disorders. This category is distinct from an acute provoked seizure due to a temporary disturbance such as hypoglycaemia or hyponatraemia; an acute provoked seizure alone does not establish epilepsy.

Autoimmune: anti-NMDA receptor encephalitis, LGI1 antibody encephalitis — immunotherapy targets the autoimmune cause; antiseizure medicines may also be needed for seizure control.

Unknown: approximately 30% of epilepsy has no identifiable cause after full investigation.

Types of Seizures

Focal Seizures

Focal aware seizures (previously simple partial): consciousness preserved. Symptoms depend on the area of cortex involved:

• Motor cortex: rhythmic jerking of a limb (Jacksonian march)
• Temporal lobe: déjà vu, jamais vu, rising epigastric sensation, emotional changes (fear, euphoria), hallucinations (smell, taste, sound)
• Occipital lobe: visual hallucinations or loss of vision
• May be the aura (warning) before a larger seizure

Focal impaired awareness seizures (previously complex partial): consciousness altered or lost. Most commonly arise from the temporal lobe:

• Staring episode lasting 30 seconds to 2 minutes
• Automatisms — semi-purposeful repetitive behaviours (lip smacking, hand fumbling, vocalisation)
• Post-ictal confusion lasting minutes to hours
• No memory of the event

Focal to bilateral tonic-clonic seizures: a focal seizure spreads to involve both hemispheres, producing a generalised convulsion. Often mistaken for a "grand mal" seizure.

Generalised Seizures

Generalised tonic-clonic (GTC, "grand mal"): the most dramatic seizure type.

• Tonic phase: sudden loss of consciousness; body stiffens; may fall; may cry out
• Clonic phase: rhythmic jerking of limbs; tongue biting; urinary incontinence; lasts 1–3 minutes
• Post-ictal: deep sleep and confusion for minutes to hours; headache and muscle aching
• Bystanders: stay calm, protect the person from injury, do not restrain them or put anything in their mouth, turn them onto their side when safe, and time the seizure. Call emergency services when a convulsive seizure reaches 5 minutes, or sooner for a first seizure, repeated seizures without recovery, breathing difficulty, serious injury or a seizure in water. Follow an available individual emergency plan without delaying needed help; in mainland China call 120.

Absence seizures (petit mal): brief, sudden lapses of consciousness lasting 5–30 seconds without falling. Blank stare, sometimes with subtle eye fluttering. No post-ictal confusion. Typically begin in childhood; associated with generalised 3 Hz spike-wave discharge on EEG. Often missed — mistaken for daydreaming.

Myoclonic seizures: sudden, brief, shock-like jerks of limbs or body; typically occur in the morning shortly after waking. Characteristic of juvenile myoclonic epilepsy (JME).

Atonic seizures (drop attacks): sudden loss of muscle tone causing abrupt falls and significant injury risk; associated with severe epilepsy syndromes (Lennox-Gastaut).

Tonic seizures: sustained stiffening of limbs or body; may cause falls.

Diagnosis

History

A detailed eyewitness account of the event is indispensable — the clinician must reconstruct what actually happened during the seizure (onset, duration, movements, awareness, recovery). Key questions: any warning (aura)? Tongue biting? Incontinence? Post-ictal confusion? Family history of epilepsy? Provoking factors?

EEG (Electroencephalogram)

The EEG is the cornerstone investigation in epilepsy. Electrodes placed on the scalp record the brain's electrical activity. EEG findings in epilepsy:

• Interictal epileptiform discharges (IEDs) — spikes, sharp waves, or spike-wave complexes — can support diagnosis and classification. Patterns may be focal or generalised; an interictal abnormality does not, by itself, establish the seizure-onset zone
• Characteristic patterns: 3 Hz spike-wave in absence epilepsy; polyspike-wave in JME; temporal spikes in mesial temporal lobe epilepsy

A normal EEG does not exclude epilepsy — IEDs are absent in 50% of routine EEGs. Prolonged ambulatory EEG or video-EEG telemetry (inpatient monitoring with simultaneous EEG and video recording) increases sensitivity and allows seizure characterisation.

MRI of the Brain

MRI is recommended for most people diagnosed with epilepsy. NICE identifies exceptions for idiopathic generalised epilepsy and self-limited epilepsy with centrotemporal spikes. MRI can identify:

• Hippocampal sclerosis — atrophy and signal change in the hippocampus; most common surgically treatable lesion
• Cortical dysplasia — abnormal cortical development; may be subtle and requires dedicated epilepsy-protocol sequences
• Brain tumours, cavernomas, gliosis, arteriovenous malformations, stroke
• MRI may be normal in generalised and genetic epilepsies

Additional Investigations

• Blood tests: glucose, sodium, calcium, magnesium, liver and renal function; prolactin level (elevated post-ictally in tonic-clonic seizures — diagnostic aid)
• Lumbar puncture: if encephalitis, meningitis, or SAH is suspected
• Genetic testing: for specific epilepsy syndromes (SCN1A for Dravet, gene panels for childhood epileptic encephalopathies)
• Autoimmune antibody panel: NMDA-R, LGI1, CASPR2, AMPA-R, GABA-B — for autoimmune encephalitis presenting with new seizures

Treatment

Antiseizure Medications (ASMs)

The majority of people with epilepsy are treated with antiseizure medications. Drug selection depends on seizure type, epilepsy syndrome, patient age, sex, comorbidities, and drug interactions.

First-line antiseizure medications:

Drug	Indication	Mechanism	Key Points
Sodium valproate	Generalised epilepsies, JME, absence	Sodium channel / GABA	Highly effective broad-spectrum; avoid in women of childbearing age (teratogen)
Levetiracetam	Focal and generalised	SV2A modulation	May cause irritability or mood changes; interactions with other medicines are possible, so review all medicines and supplements with a clinician or pharmacist
Lamotrigine	Focal and generalised; absence	Sodium channel	Among the safer antiseizure medicines studied in pregnancy, but requires individual risk–benefit review and monitoring; slow titration to reduce rash risk
Carbamazepine / oxcarbazepine	Focal seizures	Sodium channel	Very effective for focal; may worsen absence/myoclonic
Ethosuximide	Absence seizures only	Calcium channel (T-type)	Drug of choice for pure absence epilepsy
Clobazam	Adjunct	GABA-A potentiation	Useful add-on; tolerance limits long-term use
Topiramate	Focal and generalised	Multiple	Also used in migraine prevention; cognitive side effects
Lacosamide	Focal	Slow inactivation of sodium channel	IV formulation available; useful adjunct

Approximately 70% of patients achieve seizure freedom with one or two medications. Drug-resistant epilepsy means failure to achieve sustained seizure freedom after adequate trials of two ASM regimens that were appropriately selected, tolerated and correctly used, alone or in combination. A clinician should assess dose, treatment duration and adherence when deciding whether each trial was adequate.

Drug-Resistant Epilepsy

Approximately 30% of patients do not achieve seizure freedom with medication. These patients should be referred to a specialist epilepsy centre for:

Epilepsy surgery evaluation:
The most effective treatment for drug-resistant focal epilepsy. Comprehensive pre-surgical evaluation includes:

• Video-EEG telemetry to capture habitual seizures and localise the focus
• High-resolution epilepsy-protocol MRI
• Neuropsychological testing
• FDG-PET and SPECT (ictal perfusion studies)
• Intracranial EEG (stereoelectroencephalography — SEEG) when non-invasive evaluation is inconclusive

Surgery types:

• Temporal lobectomy / selective amygdalohippocampectomy — the most common and successful epilepsy operation; 60–70% seizure freedom in mesial temporal lobe epilepsy with hippocampal sclerosis
• Lesionectomy — removal of a cortical dysplasia, cavernoma, or low-grade tumour
• Corpus callosotomy — sectioning the connection between hemispheres; reduces drop attacks in Lennox-Gastaut; not curative but palliative
• Hemispherotomy / hemispherectomy — for catastrophic unilateral hemisphere epilepsy in children

Neuromodulation:

• Vagus nerve stimulation (VNS) — implanted device that stimulates the vagus nerve; reduces seizure frequency by >50% in approximately 50% of patients; rarely produces seizure freedom; good for palliative control
• Responsive neurostimulation (RNS) — brain-implanted device detects seizure onset and delivers counter-stimulation; for bilateral or unresectable foci
• Deep brain stimulation (DBS) — stimulation of the anterior thalamus (ANT-DBS) approved for focal drug-resistant epilepsy

Ketogenic diet — high-fat, very low-carbohydrate diet; reduces seizure frequency in approximately 50% of children with drug-resistant epilepsy; particularly effective in glucose transporter deficiency syndrome and Dravet syndrome.

If you are planning pregnancy or become pregnant, seek specialist advice promptly. Do not stop or change antiseizure medication on your own.

Epilepsy Care in China

For epilepsy care in China, confirm which of the following services the receiving centre can provide and which are clinically indicated:

• Comprehensive epilepsy evaluation: video-EEG telemetry, high-resolution 3T MRI, FDG-PET, SPECT and neuropsychological assessment
• Stereo-EEG (SEEG): intracranial depth electrode placement for refractory focal epilepsy; confirm whether the receiving centre offers this assessment
• Epilepsy surgery: temporal lobectomy, lesionectomy and hemispherotomy may be considered for selected patients; ask the receiving team about its relevant experience and outcomes
• Paediatric epilepsy expertise: specialist children's epilepsy teams managing infantile spasms, Dravet syndrome, and other severe childhood epilepsy syndromes
• Ketogenic diet programmes: inpatient initiation and outpatient monitoring at tertiary centres
• Cost: obtain a written, itemised hospital quote and clarify separately charged coordination services before committing; this guide does not establish comparative savings.
• Full English care navigation from pre-surgical assessment through surgery and post-operative follow-up

Contact a PriumCare care navigator to arrange an epilepsy assessment, surgical evaluation, or second opinion on drug-resistant epilepsy management.

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Sources and editorial correction

• Clinical source.
• Clinical source.
• Clinical source.
• Clinical source.

Editorial source correction: 25 October 2026. This targeted correction addresses the specific claims documented above; it is not a clinical review of the whole article. No named medical reviewer is claimed. Original publication date is retained.

Additional editorial source clarification

Editorial clarification: 25 October 2026. This targeted update addresses the specific diagnostic, treatment-selection or service claims identified in the sources below. It is not a clinical review of the whole article; the original publication date is retained.

• Source 1

Additional targeted source clarification

Editorial source check: 25 October 2026. These corrections address the specific assessment and treatment-selection statements above; this is not a whole-article medical review.

• Source 1
• Source 2
• Source 3

Targeted seizure-classification and drug-resistance clarification

Editorial source check: 26 October 2026. This checks only the generalised-seizure description and drug-resistance definition clarified above; it is not a whole-article medical review and adds no named clinical reviewer. The original publication date is retained.

• ILAE 2025: updated classification of epileptic seizures
• ILAE: definition of drug-resistant epilepsy

Targeted structural-cause and EEG clarification

Editorial source check: 26 October 2026. This update clarifies only the hippocampal-sclerosis example and the limits of interictal EEG localisation. It is not a whole-article medical review, adds no named clinical reviewer, and retains the original publication date.

• ILAE: hippocampal sclerosis overview
• ILAE 2017: epilepsy classification
• Smith et al., 2022: interictal discharges and seizure propagation

Targeted assessment and autoimmune-treatment clarification

Editorial source check: 26 October 2026. This update clarifies the search description and the roles of immunotherapy and antiseizure medicines in autoimmune encephalitis. It is not a whole-article medical review and adds no named clinical reviewer. The original publication date is retained.

• NICE NG217: diagnosis and assessment of epilepsy
• Autoimmune Encephalitis Alliance Clinicians Network: symptomatic and long-term management recommendations