Epilepsy — Symptoms, Causes & Treatment | MyMedicPlus

Epilepsy is a chronic neurological disorder characterised by a sustained predisposition to generate recurrent, unprovoked epileptic seizures — transient episodes of abnormal, excessive, or hypersynchronous neuronal activity in the brain, causing involuntary alterations in motor function, sensory experience, consciousness, or behaviour. The International League Against Epilepsy (ILAE) defines epilepsy as: two or more unprovoked seizures occurring more than 24 hours apart; one unprovoked seizure with a probability of recurrence above 60%; or diagnosis of an epilepsy syndrome. Epilepsy affects approximately 50 million people worldwide (65 million by some estimates), making it one of the most common serious neurological conditions globally — more prevalent than multiple sclerosis, Parkinson's disease, and cerebral palsy combined. Prevalence is disproportionately high in low-income countries (80% of people with epilepsy live in these regions), where infections (neurocysticercosis, cerebral malaria, meningitis) are common causes and antiepileptic drugs (AEDs) may be unavailable. Seizures are classified by the ILAE 2017 classification as focal onset (arising from one hemisphere — may or may not involve impaired awareness), generalised onset (involving both hemispheres simultaneously from the start), or unknown onset. With appropriate antiepileptic therapy, 70% of people with epilepsy achieve seizure freedom. The remaining 30% have drug-resistant epilepsy — defined as failure of two or more appropriate, tolerated, and adequately dosed AED schedules — and require evaluation for epilepsy surgery, vagus nerve stimulation, or ketogenic diet.

The ILAE classifies epilepsy aetiology into six categories, reflecting the diverse underlying mechanisms: Structural: brain lesions visible on MRI that cause epilepsy — hippocampal sclerosis (mesial temporal lobe epilepsy — the most common surgically treatable form), focal cortical dysplasia (type IIb — most commonly causes drug-resistant focal epilepsy in children and young adults), brain tumours (low-grade glioma — particularly MRI-negative in early stages), post-stroke epilepsy (occurs in 10% of stroke survivors), traumatic brain injury (late post-traumatic epilepsy develops in 5–10% with severe TBI), cavernous malformations, and tuberous sclerosis. Genetic: ion channel mutations (channelopathies) account for many idiopathic generalised epilepsies — SCN1A mutations (Dravet syndrome — severe, drug-resistant, onset in infancy), KCNQ2/3 (benign neonatal epilepsy), GRIN2A (epileptic encephalopathy), DEPDC5 (familial focal epilepsy); genetic counselling is essential. Infectious: neurocysticercosis (Taenia solium tapeworm larvae — the most common cause of acquired epilepsy in developing countries); bacterial meningitis, viral encephalitis (HSV — herpes simplex, TB). Metabolic: phenylketonuria (PKU), pyridoxine-dependent epilepsy, glucose transporter deficiency (GLUT1 — treated by ketogenic diet), electrolyte disturbances (hyponatraemia, hypoglycaemia — usually provoked seizures, not epilepsy). Immune: autoimmune encephalitis — NMDA receptor antibody encephalitis (anti-NMDAR — most common, associated with ovarian teratoma in women, causes psychosis and seizures), LGI1-antibody encephalitis (faciobrachial dystonic seizures), GABA-B antibody encephalitis. Unknown: approximately 40% of epilepsy has no identifiable cause with current investigation.

Seizure semiology depends on the brain region of onset and extent of spread. Focal seizures (arising from one hemisphere): focal aware seizures (previously 'simple partial') — consciousness preserved; motor (rhythmic jerking of contralateral limb — Jacksonian march spreading up the limb as the seizure propagates through the motor cortex), sensory (tingling, visual phenomena, smell — uncinate — or taste), autonomic (fear, epigastric rising — the most common aura in temporal lobe epilepsy, déjà vu, jamais vu), or dysphasic (if dominant hemisphere language areas involved). Focal impaired awareness seizures (previously 'complex partial') — automatisms (repetitive, purposeless movements — chewing, lip smacking, fumbling, picking) during altered consciousness; post-ictal confusion lasting minutes to hours. Focal to bilateral tonic-clonic: focal onset seizure spreading to bilateral convulsive activity (tonic stiffening followed by clonic jerking of all four limbs; eyes deviated; incontinence; cyanosis; post-ictal lethargy). Generalised onset seizures: absence seizures (brief 5–30 second staring episodes with abrupt onset and offset, eyelid flutter; 3 Hz spike-and-wave on EEG; no post-ictal phase; childhood absence epilepsy vs juvenile absence epilepsy); myoclonic jerks (sudden brief muscle contractions — typically on awakening; juvenile myoclonic epilepsy — JME); tonic-clonic (grand mal — bilateral convulsions). Epileptic spasms (infantile spasms — West syndrome): salaam attacks in infants under 12 months; EEG shows hypsarrhythmia; requires urgent ACTH or vigabatrin. Post-ictal phenomena: Todd's paresis (transient unilateral weakness after a focal motor seizure — 30–60 minutes; important differential for TIA), headache, confusion, and fatigue.

Diagnosis is clinical — a detailed witness history is the most important diagnostic tool. Two or more unprovoked seizures more than 24 hours apart are required by ILAE definition. Electroencephalogram (EEG): records cortical electrical activity via scalp electrodes; interictal epileptiform discharges (IEDs — spikes, sharp waves, spike-wave complexes) support the diagnosis of epilepsy; the specific IED pattern guides classification of the epilepsy syndrome (e.g., 3 Hz spike-wave in absence epilepsy; centrotemporal spikes in rolandic epilepsy). Normal EEG does not exclude epilepsy — 40% of people with epilepsy have a normal routine EEG. Sleep-deprived EEG increases the yield of detecting abnormalities by 20–30%. MRI brain (3T, dedicated epilepsy protocol with thin coronal cuts through hippocampi): identifies structural lesions — hippocampal sclerosis (T2/FLAIR signal change and volume loss), cortical dysplasia, tumours, cavernomas, and post-stroke changes. Normal 1.5T MRI may miss focal cortical dysplasia detectable only on 3T. Video-EEG telemetry monitoring: simultaneous video and multi-channel EEG recording during in-patient stay — the gold standard for seizure classification and pre-surgical evaluation; essential for characterising drug-resistant epilepsy and planning resection. Neuropsychological testing, ictal SPECT, PET (18F-FDG), and MEG complement video-EEG in complex surgical cases. Genetic testing: panels or whole exome sequencing for genetic epilepsies (childhood-onset, drug-resistant, family history). Blood tests: glucose, electrolytes, calcium, magnesium, renal function, LFTs, and anti-epileptic drug levels (phenytoin — narrow therapeutic window; valproate; carbamazepine). CSF analysis for autoimmune encephalitis antibody panel and infectious causes.

Antiepileptic drugs (AEDs) are first-line treatment — aiming for complete seizure freedom with minimal side effects. AED choice is determined by seizure type, epilepsy syndrome, age, sex (teratogenicity concerns), comorbidities, and drug interactions. Focal epilepsy: carbamazepine (200–1,600 mg/day) or oxcarbazepine are first-line; levetiracetam (500–3,000 mg/day), lamotrigine (target 200–600 mg/day — requires slow titration to minimise rash risk), lacosamide, and brivaracetam are alternatives. Valproate is avoided in women of childbearing age (significant teratogen — 1 in 10 babies exposed in utero has a major malformation and 30–40% have neurodevelopmental impairment — MHRA black triangle warning, 2024). Generalised epilepsy: valproate is most effective (80–90% seizure freedom in juvenile myoclonic epilepsy, JME) but teratogenic in women; lamotrigine or levetiracetam are alternatives for women. Absence epilepsy: ethosuximide (the most effective for pure absence — 2010 NETT trial) or valproate; lamotrigine is third-line. Drug-resistant epilepsy (failure of 2 AEDs — 30%): Epilepsy surgery — the most effective treatment for drug-resistant focal epilepsy; temporal lobe resection (anteromesial temporal lobe resection for hippocampal sclerosis) achieves seizure freedom in 60–80% at 5 years; temporal lobe epilepsy surgery is underutilised. Vagus nerve stimulation (VNS): implanted pulse generator delivers electrical pulses to the vagus nerve — reduces seizure frequency by 50% in one-third of patients. Responsive neurostimulation (RNS — NeuroPace): closed-loop cortical stimulation from detected seizure onset; reduces seizures in bilateral or multi-focal epilepsy unsuitable for resection. Ketogenic diet (high fat, low carbohydrate, adequate protein): seizure reduction in 50% of children with drug-resistant epilepsy; particularly effective in glucose transporter deficiency (GLUT1). Lennox-Gastaut syndrome: fenfluramine, cannabidiol (Epidyolex — for Dravet and LGS), rufinamide.

Status epilepticus (SE) — a seizure lasting more than 5 minutes, or repeated seizures without recovery in between — is a neurological emergency with 20% in-hospital mortality and significant morbidity. Convulsive SE requires immediate IV lorazepam (4 mg) or diazepam (10 mg) as first-line (ERC guidelines); if seizure continues after 5–10 minutes: IV phenytoin (15–20 mg/kg), levetiracetam (60 mg/kg, up to 4,500 mg), or sodium valproate (30–40 mg/kg) — failure to control at this stage requires general anaesthesia (thiopentone, propofol, midazolam infusion) in ICU with continuous EEG monitoring. SUDEP (sudden unexplained death in epilepsy) is the most devastating outcome — occurring in approximately 1 in 1,000 people with epilepsy per year overall (and up to 1 in 150 in uncontrolled tonic-clonic seizures); mechanism involves postictal respiratory depression, airway obstruction, and cardiac arrhythmia; the strongest risk factor is nocturnal generalised tonic-clonic seizures — nocturnal supervision or bed alarms reduce risk. Trauma from seizures: head injuries (particularly subdural haematoma from temporal lobe seizures in anticoagulated patients), dental injuries from tongue biting, and injuries from falls. Drowning: people with epilepsy have a 15–20-fold increased drowning risk versus the general population — showering rather than bathing, and never swimming alone are essential safety precautions. Cognitive impairment: long-term poorly controlled epilepsy, particularly in children, causes progressive memory and cognitive dysfunction; early seizure control preserves cognitive function. Depression (in 30–40%) and anxiety are the most common psychiatric comorbidities and are often undertreated — they significantly reduce quality of life independently of seizure control.

Consistent AED adherence is the most important preventive measure — abrupt medication cessation is the most common precipitant of seizure breakthrough and status epilepticus. Never stop or reduce AEDs without neurological guidance. Seizure triggers are personal and variable — common triggers include sleep deprivation (avoid staying up late, use of sleep study if OSA suspected), alcohol consumption (directly lowers seizure threshold and disrupts sleep), fever and intercurrent illness, stress, photosensitive stimuli (specific light-emitting patterns — affects 3% of people with epilepsy — assessed by photosensitivity testing on EEG). Lifestyle safety: wear a medical alert bracelet or wallet card specifying seizure type and emergency management; inform close contacts of first aid (do not restrain, time seizure, recovery position after convulsions stop, call 999 if lasting above 5 minutes). UK and most countries prohibit driving until seizure-free for 12 months (tonic-clonic or impaired awareness seizures) or 6 months if only nocturnal seizures — neurologists must advise on DVLA notification obligations. Women with epilepsy planning pregnancy: preconception counselling with neurologist is essential; folic acid 5 mg daily from at least 3 months before conception; valproate must be avoided in pregnancy wherever possible (MHRA 2024 guidelines); lamotrigine dose frequently needs increasing in pregnancy due to enhanced clearance. Psychosocial support via epilepsy nurse specialists, support groups (Epilepsy Action, Epilepsy Society), and access to cognitive behavioural therapy for comorbid depression and anxiety.

Call emergency services immediately for a seizure lasting more than 5 minutes (status epilepticus — a medical emergency), a second seizure occurring immediately after the first without the person regaining consciousness, a seizure in someone with no prior epilepsy diagnosis, a seizure in water (drowning risk), a seizure in a pregnant woman, or if the person is injured during the seizure. Do not restrain the person — protect the head with something soft, time the seizure, turn them onto their side after convulsive movements stop. See a neurologist promptly after a first seizure — the risk of a second seizure within 2 years is 40-50%. See your epilepsy team urgently for: a change in seizure frequency or pattern, new seizure type, or suspected SUDEP risk factors. Women with epilepsy planning pregnancy must see their neurologist before conception — medication adjustments and folic acid 5mg daily are essential.