Neurology & Pediatrics & Family Medicine
Epilepsy
Epilepsy is a chronic neurological disorder defined by the occurrence of at least two unprovoked epileptic seizures more than 24 hours apart, or by a single seizure associated with a risk of recurrence ≥60 % over the following 10 years (ILAE 2014 criteria). An epileptic seizure results from an abnormal, excessive and hypersynchronous electrical discharge from a network of cortical neurons - this discharge may be focal (limited to one hemisphere or region) or generalized (immediately involving both hemispheres). Epilepsy affects around 1 % of the world's population - or 65 million people - with a prevalence of 0.5-1 % in Canada and Quebec. Incidence is bimodal: peaking in early childhood (genetic, malformative, hypoxic causes) and in people over 65 (vascular causes - stroke, tumors, neurodegeneration). The ILAE 2017 classification distinguishes seizures according to their type of onset: focal (onset in a neural network limited to one hemisphere - formerly «partial») with or without altered consciousness, with or without secondary generalization; generalized (immediately involving both hemispheres - tonic-clonic, absences, myoclonic, atonic, tonic, clonic); and of unknown onset. Causes are classified as structural (identifiable brain lesion - tumor, cortical malformation, stroke, head trauma), genetic (identified or presumed pathogenic variant - ex. Dravet syndrome, juvenile myoclonic epilepsy), infectious (meningitis, encephalitis, neurocysticercosis), metabolic (hyponatremia, hypoglycemia, uremia - provoked seizures to be distinguished from true epilepsy), immune (autoimmune encephalitis - anti-NMDAR, anti-LGI1) and of unknown cause (the most frequent group in adults). The fundamental distinction between a provoked seizure (identifiable acute cause - hypoglycemia, alcohol abuse, fever in children, medication) and an unprovoked seizure (true epilepsy) is essential, as it determines the need for long-term antiepileptic treatment.
Classification of epilepsies and epileptic syndromes
- Focal crises: Onset in a hemispheric neural network — semiology depends on the cortical region involved; focal with preserved consciousness (formerly «simple partial»): no alteration of consciousness — motor symptoms (unilateral clonus, head deviation), sensory (unilateral paresthesias), autonomic (nausea, flush), psychic (déjà vu, jamais vu, sudden fear) → duration <2 min; focal with altered consciousness (formerly «complex»): altered consciousness + automatisms (chewing, repetitive hand gestures, wandering) - characteristic of temporal lobe epilepsy (temporal lobe - hippocampus, amygdala); focal with secondary bilateral tonic-clonic generalization: spread to both hemispheres → generalized tonic-clonic seizure with initial focal aura
- Widespread crises: Generalized tonic-clonic (GTC) seizure («grand mal»): tonic phase (generalized muscle rigidity + apnea + cyanosis → 10–30 sec) followed by a clonic phase (rhythmic bilateral muscle jerks → 30–120 sec) + post-critical phase (confusion, somnolence, headache — 15 min to several hours) + amnesia of the seizure; typical absence seizures (petit mal): sudden interruption of consciousness + fixed stare + cessation of activity × 5–20 seconds + immediate resumption without post-critical period — typical in children (childhood absence epilepsy — CAE) — may go unnoticed; myoclonus: brief bilateral muscle jerks (often morning, before/after waking) — typical of juvenile myoclonic epilepsy (JME); atonic seizures (drop attacks): sudden loss of postural tone → fall → frequent trauma — Lennox-Gastaut syndrome
- Major epileptic syndromes: Mesial temporal lobe epilepsy (MTLE) — most frequent syndrome in adults — hippocampal sclerosis on MRI — focal seizures with automatisms — resistance to antiepileptics in 30–40 %of cases → effective surgery (anterior temporal lobectomy — 60–70 % seizure-free at 2 years); Juvenile myoclonic epilepsy (JME): onset 12–18 years — morning myoclonus + GTC + absence seizures — sensitive to valproate (efficacy >85 % ) — lifelong treatment often necessary; West syndrome (infantile spasms): infants 3–12 months — triad of spasms + hypsarrhythmia on EEG + developmental regression — treatment: ACTH or vigabatrin; Dravet syndrome: severe epileptic encephalopathy of infancy — SCN1A mutation — prolonged febrile seizures + drug-resistant polytherapy — avoid carbamazepine/phenytoin (worsen)
- Differential diagnosis of seizures: syncope (cardio-vagal, orthostatic, cardiac) — possible post-anoxic myoclonus at the end of syncope (caution not to confuse); panic attack (hyperventilation, perioral paresthesia, no post-event phase); transient ischemic attack (TIA) — negative neurological deficits without seizures usually; psychogenic nonepileptic seizure (PNES) — pseudoseizure — motor manifestations without EEG correlate — triggered by stress — more common in women — video-EEG is the gold standard for differentiation; hypoglycemia; migraine with aura; narcolepsy-cataplexy; parasomnias (night terrors, sleepwalking)
Diagnosis and treatment
| Appearance / Treatment | Mechanism, technique and procedures | Interpretation, targets and precautions |
|---|---|---|
| EEG and video-EEG Central diagnostic tool |
Routine electroencephalogram (EEG): recording of cortical electrical activity via 19–21 surface electrodes × 20–40 min — including hyperventilation activation (3 min — provokes absence seizures) and intermittent photic stimulation (photosensitivity); interictal epileptiform abnormalities (IEAs): spikes, spike-waves, polyspikes → confirm epilepsy diagnosis + inform about type (focal = focal epilepsy; diffuse generalization = generalized epilepsy); sleep deprivation EEG: increases yield by 20–30 % (epileptiform abnormalities are more frequent during the wake-sleep transition and slow-wave sleep); prolonged video-EEG (inpatient monitoring): gold standard for seizure classification + PNES differentiation + presurgical assessment (localization of the epileptogenic focus) | Routine EEG is normal in 50 % of epileptic patients (interictally) — a normal EEG does not exclude the diagnosis of epilepsy; the sensitivity of a single EEG is 29–55 % — increases to 80–90 % after 3 serial EEGs; EEG should not be used alone to diagnose or exclude epilepsy — diagnosis remains clinical + EEG + MRI; non-epileptiform EEG abnormalities (focal or diffuse slow waves): signal brain dysfunction but do not confirm epilepsy — to be interpreted in context; emergency EEG: indicated if non-convulsive status epilepticus (NCSE) is suspected in a confused/stuporous patient |
| Brain MRI Mandatory etiological assessment |
Brain MRI with epilepsy protocol (millimeter slices + volumetric MPRAGE T1 sequences, T2, FLAIR, T2* or SWI susceptibility, DWI diffusion): detection of structural causes (hippocampal sclerosis - atrophy + hippocampal FLAIR hyperintensity - most frequent cause of refractory temporal epilepsy; focal cortical dysplasia - cortical thickening, abnormal gyrification; low-grade glial tumors - oligodendroglioma, ganglioglioma; cavernomas - SWI/T2*; vascular malformations; ischemic lesions; focal atrophy); 3 Tesla MRI: superior to 1.5 T for small lesions - recommended in the workup of pharmacoresistant focal epilepsy; 18F-FDG PET + ictal SPECT: presurgical evaluation - localization of the interictal hypometabolic focus (PET) or ictal hyperperfused area (SPECT) | MRI is indicated in any patient with a first unprovoked seizure or a newly established epilepsy diagnosis—except typical childhood idiopathic generalized epilepsy (absences, JME) where MRI may be normal and is sometimes deferred; CT scan of the brain: acceptable in emergencies (first seizure—rule out hemorrhage, large tumor) but insufficient for complete etiological workup—MRI mandatory afterward; normal MRI in 30–40 % of focal epilepsies—does not reduce the need for treatment; molecular genetics (epilepsy NGS panel): indicated for epilepsy starting <2 years of age + epileptic encephalopathy + suspected genetic syndrome + negative workup in a child |
| First-line antiepileptics — adult Pharmacological treatment — choice according to seizure type |
Focal epilepsy: levetiracetam (Keppra) 500–3,000 mg/day × 2 doses — mechanism: binds to synaptic vesicle protein SV2A — first-line (minimal hepatic metabolism, no interactions, no biological monitoring); lamotrigine (Lamictal) 100–400 mg/day × 2 doses — blocks voltage-gated Na+ channels — first-line, good tolerance, safe in pregnancy (doses to be adjusted) — very slow introduction (↓ risk of Stevens-Johnson rash); lacosamide (Vimpat) 200–400 mg/day × 2 doses — slow inactivation of Na+ channels — second-line focal; Generalized epilepsy: valproate (Epival) 750–2,000 mg/day × 2–3 doses — broad spectrum (GTC + absences + myoclonias) — first-line in men + menopausal women (teratogenic — contraindication in pregnancy + women of childbearing potential without effective contraception — SGLT2 Canada 2023); levetiracetam + lamotrigine: alternatives in women of childbearing potential | The choice of antiepileptic drug (AED) depends on the type of seizure/syndrome, sex, age, comorbidities, and side effect profile; essential rule: never use carbamazepine, phenytoin, or oxcarbazepine in idiopathic generalized epilepsies (IGE, absence seizures) — risk of worsening myoclonus and absence seizures; valproate: absolute contraindication in pregnancy (major congenital malformations 10 %— spina bifida, heart defects — + neurodevelopmental disorders 30–40 % ) — pregnancy prevention program (PPP) mandatory in Canada since 2023 for all women of childbearing age; lamotrigine: severe rash (Stevens-Johnson) if introduced too quickly — respect titration over 8–12 weeks; valproate biological monitoring: liver function tests + CBC + ammonia if symptomatic |
| Antiepileptics — Special Populations Pregnancy, child, elderly person |
Pregnancy: lamotrigine (1st line - doses to be increased by 25-50 % as clearance is increased by estrogen - serum levels to be monitored); levetiracetam (2nd line - reassuring safety data); folic acid 5 mg/day preconception and 1st trimester (all MAEs increase risk of neural tube defects); avoid carbamazepine (cleft palate) and phenytoin (hydantoin fetal syndrome); valproate: absolute contraindication; Child: ethosuximide (Zarontin) 20-40 mg/kg/d : 1st line for childhood absences (EAE) - superior to valproate on cognitive tolerance (NAETC 2010 study - NEJM); vigabatrin (Sabril): 1st line infantile spasms (West syndrome) associated with tuberosclerosis; stiripentol + clobazam + valproate: Dravet syndrome; Elderly: levetiracetam, lamotrigine, lacosamide - avoid valproate (tremors, hyperammonemic encephalopathy), carbamazepine (hyponatremia, interactions), phenytoin (phenytoin toxicity - dose-dependent saturation) | Women of childbearing age with epilepsy should be informed of teratogenic risks before any pregnancy—mandatory preconception planning with the treating neurologist; breastfeeding: levetiracetam and lamotrigine pass into breast milk—monitor infant sedation; elderly: new-onset epilepsy after age 60 is often vascular in origin (post-stroke) → carbamazepine and lamotrigine as first-line if focal seizure; drug interactions in the elderly: carbamazepine (potent enzyme inducer) + warfarin, statins, digoxin—reduces the efficacy of these medications; gabapentin and pregabalin: useful if associated neuropathic pain but marked sedation and risk of falls in the elderly |
| Drug-resistant epilepsy and surgery Failure of 2 well-conducted RAPs |
Pharmacoresistance: defined by failure of at least 2 well-chosen and well-tolerated MAEs at adequate doses (ILAE 2010) - concerns 30-40 % of epileptic patients; pre-surgical workup: prolonged video-EEG (localization of focus) + 3T MRI epilepsy protocol + PET-FDG + ictal SPECT ± intracranial EEG (stereotactic electrodes - SEEG) for complex cases; resective surgery: anterior temporal lobectomy (mesial temporal epilepsy - hippocampal sclerosis) → 60-70 % of seizure-free patients at 2 years (Wiebe 2001 - NEJM - RCT); resection of structural lesion (tumor, cortical dysplasia); vagus nerve stimulation (VNS): seizure reduction ≥50 % in 40-50 % of cases - palliative option if non-surgical; deep brain stimulation (DBS) of the anterior nucleus of the thalamus (SANTE trial): reduction ≥50 % in 40 %; ketogenic diet: effective in drug-resistant pediatric epilepsy - reduction ≥50 % in 50 % of children (Neal 2008 - Lancet) | Referral to a tertiary epilepsy center should be made early after failure of 2 AEDs; do not delay surgical evaluation (each year of uncontrolled seizures = risk of SUDEP + cognitive decline + accidents); SUDEP (sudden unexpected death in epilepsy): unexplained sudden death in an epileptic - incidence 1-2/1000 patient-years (adults) - risk factors: frequent nocturnal generalized tonic-clonic seizures, non-compliance with treatment, alcohol - prevention: control of generalized tonic-clonic seizures + nocturnal monitoring + avoid isolation; driver's license in Quebec: mandatory 12-month suspension after the last seizure - report to the examining physician of the SAAQ - the physician is obligated to report if the patient refuses to do so (Act respecting the protection of persons). |
ℹ️
Driving and epilepsy in Quebec: Quebec regulations (SAAQ) require a 12-month driving ban after the last unprovoked epileptic seizure before being able to have their driver's license reinstated (passenger vehicle). For heavy vehicles (Class 1–4), the abstinence period is 5 years without a crisis. A first induced crisis (acute cause treated and corrected) may allow a return to driving after 3-6 months, depending on the cause. The treating physician has the'Legal obligation Report to the SAAQ examining physician any patient with a diagnosis of epilepsy or a disorder that could affect road safety if the patient refuses to do so themselves. The final decision rests with the SAAQ examining physician, not the treating physician.
Emergency — Status Epilepticus
Dial 911 immediately if a crisis lasts more than 5 minutes or if the patient does not regain consciousness between seizures. Status epilepticus (SE) is defined as a seizure >5 minutes or repeated seizures without return to consciousness—a neurological emergency with a mortality of 10-20% % and a risk of irreversible brain damage if not treated promptly.
First aid during a seizure: protect the head (pillow) → place in the recovery position (PLS) at the end of the seizure → do not put fingers or objects in the mouth → do not restrain movements → time the duration of the seizure → call 911 if seizure >5 min, it's the first seizure, there's an injury, or if pregnant or in status epilepticus.
Pre-hospital treatment: midazolam intranasal or oral (Buccolam) 10 mg (adult) — available by prescription for known epileptic patients — to be administered from the 5th minute if seizure persists.
Consult at Clinique Omicron
Clinique Omicron physicians evaluate patients after a first seizure — initial workup (blood glucose, electrolytes, CBC, ECG, brain CT), order EEG and brain MRI, refer to neurology, and counsel on temporary restrictions (driving, swimming, working at heights). Follow-up for stable epileptic patients under treatment, monitoring for antiepileptic side effects, and managing drug interactions are provided at our service points in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.
The content of this page is for informational purposes only and does not replace the advice of a qualified healthcare professional. Any seizure lasting longer than 5 minutes or a first-time seizure requires urgent medical attention.
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