Clinical Approach to Seizure
Comprehensive Practical Framework1. Symptom Overview
Understanding the clinical significance and classification of seizures
Seizures represent one of the most common neurological emergencies, affecting approximately 8-10% of the general population who will experience at least one seizure during their lifetime. Epilepsy, defined as recurrent unprovoked seizures, has a prevalence of 0.5-1% worldwide, with approximately 3 million adults in the United States living with active epilepsy. Seizures account for approximately 1-2% of all emergency department visits and represent a significant source of morbidity, mortality, and healthcare expenditure. The risk of sudden unexpected death in epilepsy (SUDEP) occurs in approximately 1 per 1,000 patients with epilepsy per year, making accurate diagnosis and management critically important.
Definition
A seizure is a transient occurrence of signs and/or symptoms resulting from abnormal, excessive, or synchronous neuronal activity in the brain. This paroxysmal electrical disturbance may manifest as alterations in motor activity, sensation, behavior, awareness, or autonomic function. Epilepsy is defined as: (1) at least two unprovoked seizures occurring more than 24 hours apart; (2) one unprovoked seizure with a probability of further seizures similar to the general recurrence risk after two unprovoked seizures (≥60%) over the next 10 years; or (3) diagnosis of an epilepsy syndrome.
Key Epidemiology
- Lifetime risk of seizure: 8-10% of the general population
- Prevalence of epilepsy: 0.5-1% (approximately 50 million people worldwide)
- Incidence: Bimodal distribution — highest in children under 1 year and adults over 65 years
- First unprovoked seizure recurrence risk: 40-50% within 2 years
- Status epilepticus mortality: 15-22% in adults
Classification by Seizure Type (ILAE 2017)
| Category | Onset | Characteristics | Clinical Significance |
|---|---|---|---|
| Focal Onset | One hemisphere | Aware or impaired awareness; motor or non-motor onset; may evolve to bilateral tonic-clonic | Suggests localized structural or functional abnormality; amenable to surgical evaluation |
| Generalized Onset | Both hemispheres simultaneously | Motor (tonic-clonic, tonic, clonic, myoclonic, atonic) or non-motor (absence) | Often genetic etiology; typically responds to broad-spectrum antiseizure medications |
| Unknown Onset | Cannot be determined | Insufficient information or unwitnessed event | Requires further evaluation; may be reclassified with additional data |
Classification by Etiology
Provoked (Acute Symptomatic) Seizures
Seizures occurring in close temporal relationship with an acute systemic, metabolic, or central nervous system insult. These do not constitute epilepsy and typically do not require long-term antiseizure medication.
- Metabolic derangements (hypoglycemia, hyponatremia, uremia)
- Drug toxicity or withdrawal (alcohol, benzodiazepines)
- Acute head trauma (within 7 days)
- Acute stroke (within 7 days)
- Central nervous system infection
- Fever (febrile seizures — pediatric consideration)
Unprovoked Seizures
Seizures occurring without an identifiable acute precipitant. Two or more unprovoked seizures define epilepsy and typically warrant long-term antiseizure medication.
- Structural: Remote stroke, traumatic brain injury, tumor, vascular malformation
- Genetic: Known or presumed genetic mutation
- Infectious: Post-encephalitic, neurocysticercosis
- Metabolic: Inborn errors of metabolism
- Immune: Autoimmune encephalitis
- Unknown: No identifiable etiology
Classification by Duration and Severity
| Category | Duration | Clinical Features | Management Implications |
|---|---|---|---|
| Self-limited seizure | Less than 5 minutes | Spontaneous termination; post-ictal recovery | Supportive care; investigate if first seizure or change in pattern |
| Prolonged seizure | 5-30 minutes | Requires intervention for termination | Administer benzodiazepines; prepare for escalation |
| Status epilepticus | Greater than 5 minutes (convulsive) or greater than 10 minutes (non-convulsive) | Ongoing seizure activity or recurrent seizures without return to baseline | Medical emergency — aggressive treatment protocol; high morbidity and mortality |
| Refractory status epilepticus | Persists despite first and second-line treatment | Continued seizures after adequate benzodiazepine and antiseizure medication | Anesthetic agents; intensive care unit admission; continuous electroencephalography monitoring |
Focal Seizure Semiology by Lobe of Origin
| Lobe | Common Manifestations | Distinguishing Features |
|---|---|---|
| Temporal | Aura (epigastric rising, déjà vu, fear), automatisms (oral, manual), impaired awareness | Most common focal epilepsy in adults; often medication-resistant; surgical candidate |
| Frontal | Brief, frequent, nocturnal; hypermotor movements, fencing posture, vocalization | Rapid secondary generalization; often bizarre movements mistaken for psychogenic events |
| Parietal | Sensory symptoms (tingling, numbness), distorted body image, spatial disorientation | Less common; may have negative symptoms (loss of awareness of body part) |
| Occipital | Visual phenomena (flashing lights, colors, formed hallucinations), eye deviation, ictal blindness | May spread anteriorly causing temporal or frontal features; differentiate from migraine aura |
Generalized Seizure Subtypes
| Type | Motor Features | Duration | Associated Syndromes |
|---|---|---|---|
| Generalized tonic-clonic | Tonic stiffening followed by clonic jerking; loss of consciousness | 1-3 minutes typically | Juvenile myoclonic epilepsy, genetic generalized epilepsies |
| Absence | Behavioral arrest, staring, subtle automatisms; abrupt onset and offset | 5-30 seconds | Childhood absence epilepsy, juvenile absence epilepsy |
| Myoclonic | Brief, shock-like jerks; usually bilateral upper extremities | Less than 1 second | Juvenile myoclonic epilepsy, progressive myoclonic epilepsies |
| Atonic | Sudden loss of muscle tone; drop attacks | 1-2 seconds | Lennox-Gastaut syndrome, Dravet syndrome |
| Tonic | Sustained muscle contraction; may cause falls | 10-60 seconds | Lennox-Gastaut syndrome |
| Clonic | Rhythmic jerking without preceding tonic phase | Variable | Less common in adults |
Key Concept: The Critical First Questions
- Was this truly a seizure? — Differentiate from syncope, psychogenic events, movement disorders, and other mimics
- If seizure, was it provoked or unprovoked? — Determines need for long-term antiseizure medication
- What is the seizure type and likely localization? — Guides further workup and treatment selection
- Is this an emergency? — Identify status epilepticus, acute symptomatic causes requiring urgent intervention
2. Pathophysiology and Mechanisms
Understanding the underlying mechanisms of seizure generation and propagation
Seizures arise from an imbalance between excitatory and inhibitory neuronal activity, resulting in hypersynchronous electrical discharges. Understanding the mechanisms of seizure generation (ictogenesis) and the development of epilepsy (epileptogenesis) is essential for rational treatment selection and recognizing why certain conditions predispose to seizures. The fundamental principle is that anything causing excessive excitation, reduced inhibition, or abnormal neuronal connectivity can lower the seizure threshold.
Normal Excitation-Inhibition Balance
| Component | Excitatory System | Inhibitory System |
|---|---|---|
| Primary neurotransmitter | Glutamate | Gamma-aminobutyric acid (GABA) |
| Key receptors | NMDA, AMPA, kainate receptors | GABA-A (ionotropic), GABA-B (metabotropic) |
| Ion channel effect | Sodium and calcium influx → depolarization | Chloride influx → hyperpolarization |
| Clinical relevance | Excessive glutamate activity causes excitotoxicity and seizures | GABA enhancement is the mechanism of benzodiazepines and barbiturates |
Mechanisms of Seizure Generation (Ictogenesis)
Increased Excitation
Glutamate excess: Hypoxia, hypoglycemia, trauma
Sodium channel dysfunction: Gain-of-function mutations, drug toxicity
Calcium channel abnormalities: Enhanced calcium influx promotes depolarization
Clinical examples: Traumatic brain injury, pro-convulsant medications, genetic channelopathies
Decreased Inhibition
GABA deficiency: Pyridoxine deficiency, isoniazid toxicity
GABA-A receptor dysfunction: Benzodiazepine/alcohol withdrawal
Chloride gradient disruption: Altered chloride transporters
Clinical examples: Alcohol withdrawal seizures, benzodiazepine withdrawal, anti-GABA receptor antibodies
Abnormal Connectivity
Synaptic reorganization: Mossy fiber sprouting in hippocampal sclerosis
Gliosis: Astrocyte dysfunction, impaired glutamate clearance
Network changes: Altered thalamocortical circuits
Clinical examples: Mesial temporal sclerosis, post-traumatic epilepsy, cortical dysplasia
Cellular Mechanisms of Seizure Activity
| Mechanism | Description | Clinical Relevance |
|---|---|---|
| Paroxysmal depolarizing shift (PDS) | Large, prolonged depolarization in a group of neurons leading to burst firing | The cellular hallmark of epileptiform activity; represents the “building block” of seizures |
| Hypersynchronization | Simultaneous firing of large neuronal populations due to enhanced gap junctions and ephaptic transmission | Creates the large-amplitude electroencephalography signals seen during seizures |
| Failure of surround inhibition | Normally, excited neurons activate surrounding inhibitory interneurons to contain spread | When inhibition fails, seizure activity propagates to adjacent cortex |
| Kindling | Repeated subthreshold stimulation eventually produces spontaneous seizures | Explains progressive worsening of some epilepsies; “seizures beget seizures” |
Ion Channels and Their Role in Seizures
| Channel Type | Normal Function | Dysfunction Effect | Associated Conditions/Drugs |
|---|---|---|---|
| Voltage-gated sodium channels | Action potential initiation and propagation | Gain-of-function → hyperexcitability; Loss-of-function → can also cause seizures via interneuron dysfunction | SCN1A mutations (Dravet syndrome); phenytoin, carbamazepine, lamotrigine block these channels |
| Voltage-gated calcium channels | Neurotransmitter release, dendritic integration | T-type channel abnormalities → absence seizures | Ethosuximide blocks T-type calcium channels; effective for absence seizures |
| Voltage-gated potassium channels | Repolarization, setting resting membrane potential | Loss-of-function → prolonged depolarization, repetitive firing | KCNQ2/3 mutations (benign familial neonatal seizures); retigabine opens these channels |
| GABA-A receptors (ligand-gated chloride channels) | Fast inhibitory synaptic transmission | Reduced function → decreased inhibition | Benzodiazepines and barbiturates enhance GABA-A function; withdrawal causes seizures |
How Metabolic Derangements Cause Seizures
| Condition | Mechanism | Threshold/Clinical Notes |
|---|---|---|
| Hypoglycemia | Glucose is the primary neuronal fuel; deficiency causes ATP depletion, failure of Na+/K+-ATPase, and membrane depolarization | Usually occurs below 40 mg/dL; may cause focal or generalized seizures |
| Hyponatremia | Osmotic swelling of neurons increases membrane excitability; rate of change is critical | Risk increases significantly below 120 mEq/L or with rapid decline; correct slowly to avoid osmotic demyelination |
| Hypocalcemia | Calcium stabilizes neuronal membranes; low levels lower threshold for action potential generation | Usually with ionized calcium below 0.8 mmol/L; may see tetany before seizures |
| Hypomagnesemia | Magnesium blocks NMDA receptors; deficiency enhances glutamatergic transmission | Often coexists with hypocalcemia; important in eclampsia (magnesium sulfate is treatment of choice) |
| Uremia | Accumulation of uremic toxins, electrolyte disturbances, and metabolic acidosis all contribute | Seizures occur in severe renal failure; myoclonus is also common |
| Hepatic encephalopathy | Ammonia toxicity, false neurotransmitters, altered GABA-ergic tone | Seizures less common than in uremia; asterixis and altered consciousness more typical |
Drug and Toxin Mechanisms
Pro-convulsant Mechanisms
- GABA antagonism: Isoniazid (depletes pyridoxine → reduced GABA synthesis), fluoroquinolones, beta-lactams at high doses
- Enhanced glutamate: Tramadol, certain synthetic cannabinoids
- Sodium channel activation: Local anesthetic toxicity, bupropion
- Withdrawal syndromes: Alcohol, benzodiazepines, barbiturates (GABA-A receptor downregulation)
- Lowered threshold: Theophylline, sympathomimetics, anticholinergics
Anticonvulsant Mechanisms
- Sodium channel blockade: Phenytoin, carbamazepine, lamotrigine, lacosamide
- GABA enhancement: Benzodiazepines (allosteric modulators), barbiturates, vigabatrin (GABA transaminase inhibitor)
- Calcium channel blockade: Ethosuximide (T-type), pregabalin/gabapentin (alpha-2-delta subunit)
- Glutamate inhibition: Perampanel (AMPA antagonist), topiramate (partial)
- Synaptic vesicle modulation: Levetiracetam (SV2A binding)
Epileptogenesis: From Brain Injury to Epilepsy
Epileptogenesis is the process by which a normal brain becomes capable of generating spontaneous, recurrent seizures. This typically involves a latent period between an initial insult and the first unprovoked seizure.
| Stage | Timeline | Key Processes |
|---|---|---|
| Initial insult | Acute phase | Neuronal death, blood-brain barrier disruption, inflammation, excitotoxicity |
| Latent period | Weeks to years | Synaptic reorganization, neurogenesis, gliosis, channel expression changes, network remodeling |
| Chronic epilepsy | Ongoing | Spontaneous recurrent seizures, progressive changes, potential for drug resistance |
Seizure Propagation Pathways
| Origin | Primary Spread Pattern | Secondary Generalization |
|---|---|---|
| Temporal lobe | Hippocampus → entorhinal cortex → contralateral temporal lobe | Via thalamus and corpus callosum; may take 30-60 seconds to generalize |
| Frontal lobe | Rapid bilateral spread via corpus callosum and subcortical structures | Very rapid secondary generalization; may appear generalized from onset |
| Generalized onset | Thalamocortical networks involved from onset | Bilateral synchronous activity; classic 3 Hz spike-wave in absence seizures |
Often Overlooked Mechanism: Autoimmune Encephalitis
Autoimmune encephalitis is an increasingly recognized cause of new-onset seizures, particularly in young adults. Antibodies against neuronal surface antigens (NMDA receptor, LGI1, CASPR2, GABA-B receptor) directly alter synaptic function. Key clinical clues: subacute onset, psychiatric symptoms, memory impairment, movement disorders, and seizures that are refractory to standard antiseizure medications. Early immunotherapy can be disease-modifying. Always consider autoimmune encephalitis in new-onset refractory status epilepticus (NORSE) of unknown etiology.
Pathophysiology of Status Epilepticus
Why Status Epilepticus Is a Medical Emergency
Prolonged seizure activity leads to progressive pathophysiological changes that make seizures harder to terminate and cause neuronal injury:
- GABA-A receptor internalization: After 5-10 minutes, GABA-A receptors are internalized, reducing benzodiazepine effectiveness
- NMDA receptor externalization: Enhanced glutamatergic excitation as seizures continue
- Excitotoxic injury: Calcium overload leads to neuronal death, particularly in hippocampus
- Systemic complications: Hyperthermia, rhabdomyolysis, acidosis, cardiovascular instability
- Time-dependent treatment resistance: The longer the seizure, the more refractory it becomes to treatment
3. History Taking
A comprehensive approach to eliciting the seizure history
Red Flags — Require Urgent Evaluation
- Prolonged seizure (>5 minutes) — Status epilepticus; immediate treatment required
- Multiple seizures without recovery — Status epilepticus; high mortality risk
- First seizure with focal neurological deficit — Structural lesion (stroke, tumor, abscess)
- Seizure with fever and neck stiffness — Meningitis or encephalitis
- New seizure in immunocompromised patient — Central nervous system infection or malignancy
- Seizure with severe headache — Subarachnoid hemorrhage, cerebral venous thrombosis
- Seizure in pregnancy/postpartum — Eclampsia, posterior reversible encephalopathy syndrome, cerebral venous thrombosis
- Seizure with anticoagulation or head trauma — Intracranial hemorrhage
- New seizure in cancer patient — Brain metastases, paraneoplastic syndrome, leptomeningeal disease
- Progressive confusion after seizure (>30 minutes) — Non-convulsive status epilepticus, Todd’s paralysis with underlying lesion
Critical Principle: The patient often has no memory of the seizure. Witness history is essential. Always attempt to contact someone who observed the event. Video recordings on smartphones are invaluable for characterizing the semiology.
Systematic History: The “SEIZURE” Approach
Use the mnemonic “SEIZURE” to ensure comprehensive history taking:
- S — Setting and Start: Where were you? What were you doing? What was the very first thing that happened? Any warning or aura?
- E — Evolution and Events: How did the episode progress? What movements occurred? Was consciousness affected? How long did it last?
- I — Ictal details: Eye deviation? Head turning? Limb involvement (unilateral vs bilateral)? Automatisms? Incontinence? Tongue biting?
- Z — Zero-in on post-ictal state: Confusion? Sleepiness? Weakness (Todd’s paralysis)? Headache? How long to return to normal?
- U — Underlying causes: Sleep deprivation? Alcohol/drug use or withdrawal? Missed medications? Illness? Metabolic stressors?
- R — Risk factors and past events: Prior seizures? Head injury? Stroke? Brain surgery? Family history of epilepsy? Febrile seizures as a child?
- E — Effects on life: Impact on driving, work, relationships? Previous investigations and treatments?
Key Questions to Differentiate Seizures from Mimics
| Feature | Suggests Epileptic Seizure | Suggests Syncope | Suggests Psychogenic Non-Epileptic Seizure |
|---|---|---|---|
| Trigger/setting | Sleep deprivation, flashing lights, alcohol withdrawal | Prolonged standing, pain, heat, emotional stress, micturition | Emotional stressor, presence of audience, medical settings |
| Prodrome/warning | Stereotyped aura (déjà vu, epigastric rising, fear) | Lightheadedness, tunnel vision, warmth, nausea | Variable, may be prolonged; anxiety, palpitations |
| Onset | Sudden; may have brief warning | Gradual onset; may be prevented by sitting/lying | Gradual; often with eyes closed |
| Duration | Usually 1-3 minutes (tonic-clonic) | Seconds to less than 1 minute | Often prolonged (>5 minutes); variable |
| Motor activity | Rhythmic, synchronous; evolves over time | Brief myoclonic jerks may occur (convulsive syncope) | Asynchronous, waxing/waning, side-to-side head movement, pelvic thrusting |
| Eyes | Open, deviated; pupils dilated and unreactive | Open or closed; eyes may roll up | Closed (often forcefully); resist opening |
| Injury | Lateral tongue bite, shoulder dislocation, facial injury | Injury from fall possible; tongue tip bite | Injury uncommon; if present, usually minor |
| Post-ictal state | Confusion, fatigue, headache; minutes to hours | Rapid recovery (seconds to minutes); mild fatigue | Variable; may be rapid; tearfulness common |
Targeted Questions by Suspected Cause
| Suspected Cause | Key Features | Ask This Question |
|---|---|---|
| Alcohol withdrawal | Seizure 6-48 hours after last drink; history of heavy use | “When was your last alcoholic drink? How much do you typically drink per day?” |
| Benzodiazepine/barbiturate withdrawal | Abrupt discontinuation; may occur later than alcohol withdrawal | “Have you recently stopped or reduced any sleeping pills, anxiety medications, or sedatives?” |
| Drug toxicity | New medication, overdose, drug interaction | “Have you started any new medications recently? Could you have taken too much of any medication?” |
| Hypoglycemia | Diabetic patient; missed meal, excess insulin | “Are you diabetic? Did you take your insulin/medication? When did you last eat?” |
| Sleep deprivation | Known trigger for genetic generalized epilepsies | “How many hours did you sleep last night? Have you had significant sleep loss recently?” |
| Medication non-adherence | Known epilepsy patient with breakthrough seizure | “Have you missed any doses of your seizure medication? Have you had any trouble getting your prescription filled?” |
| Central nervous system infection | Fever, headache, altered mental status, neck stiffness | “Have you had fever, severe headache, or neck pain? Any recent infections or travel?” |
| Structural lesion (tumor, stroke) | New focal seizure; progressive symptoms; risk factors | “Have you had any weakness, numbness, vision changes, or headaches? Any history of cancer?” |
| Autoimmune encephalitis | Subacute onset; psychiatric symptoms; memory problems; movement disorders | “Over the past weeks, have you noticed personality changes, memory problems, or unusual movements?” |
| Eclampsia | Pregnant or postpartum; hypertension; edema; proteinuria | “Are you pregnant or have you recently given birth? Any headaches, vision changes, or swelling?” |
Aura Types and Their Localizing Value
| Aura Type | Description | Likely Origin |
|---|---|---|
| Epigastric rising sensation | “A feeling rising from my stomach to my chest/throat” | Mesial temporal lobe (most common aura in temporal lobe epilepsy) |
| Déjà vu / Jamais vu | Intense familiarity or unfamiliarity with surroundings | Temporal lobe (hippocampus, parahippocampal gyrus) |
| Fear or anxiety | Sudden intense fear without external cause | Amygdala (mesial temporal lobe) |
| Olfactory or gustatory | Unpleasant smell (burning, feces) or taste | Mesial temporal lobe; consider uncal herniation if acute |
| Visual (elementary) | Flashing lights, colors, geometric shapes | Occipital lobe (primary visual cortex) |
| Visual (complex) | Formed hallucinations (faces, scenes) | Temporal-occipital junction |
| Somatosensory | Tingling, numbness; may march along body part | Parietal lobe (primary sensory cortex) |
| Auditory | Buzzing, ringing, or complex sounds/voices | Superior temporal gyrus |
Medication and Substance History
Medications That Can Cause Seizures
- Antibiotics: Fluoroquinolones (especially with renal impairment), carbapenems (imipenem), isoniazid, metronidazole (high dose)
- Psychiatric medications: Bupropion, clozapine, tricyclic antidepressants (overdose), lithium toxicity
- Analgesics: Tramadol, meperidine (normeperidine accumulation)
- Immunosuppressants: Cyclosporine, tacrolimus (especially with hypomagnesemia)
- Chemotherapy: Busulfan, cisplatin, methotrexate (intrathecal)
- Local anesthetics: Lidocaine toxicity
- Others: Theophylline, baclofen withdrawal, insulin (hypoglycemia)
Substances and Withdrawal
- Alcohol: Withdrawal seizures 6-48 hours after last drink; heavy chronic use
- Benzodiazepines: Withdrawal can be life-threatening; seizures 2-7 days after cessation
- Barbiturates: Withdrawal similar to alcohol/benzodiazepines
- Cocaine: Acute intoxication (sympathomimetic); may cause stroke leading to seizures
- Amphetamines/MDMA: Acute intoxication; hyperthermia; hyponatremia (MDMA)
- Synthetic cannabinoids: Increasingly recognized cause of seizures
- GHB (gamma-hydroxybutyrate): Withdrawal can cause seizures
Relevant Past Medical and Family History
Past Medical History
- Previous seizures: Type, frequency, age of onset, response to treatment
- Head trauma: Especially with loss of consciousness, skull fracture, or intracranial hemorrhage
- Stroke or transient ischemic attack: Major risk factor for late-onset epilepsy
- Brain surgery or tumor: Surgical scars and lesions are epileptogenic
- Central nervous system infection: Meningitis, encephalitis, neurocysticercosis
- Perinatal complications: Hypoxic-ischemic injury, prematurity
- Developmental delay: Associated with many epilepsy syndromes
- Autoimmune disease: Increases risk of autoimmune encephalitis
Family History
- Epilepsy: Genetic generalized epilepsies have strong familial component
- Febrile seizures: Family history increases risk
- Sudden unexplained death: Consider genetic cardiac arrhythmia syndromes (Long QT, Brugada) — can mimic seizures
- Neurodegenerative disease: Some cause seizures (e.g., Huntington disease, Alzheimer disease)
- Metabolic disorders: Mitochondrial disease, storage disorders
Social History
- Occupation: Driving, operating machinery, heights (safety implications)
- Driving status: Legal requirements for reporting vary by jurisdiction
- Living situation: Alone vs. with others (safety concerns)
Essential Questions for the Witness
- “Can you show me what the movements looked like?” (Imitation is often more accurate than description)
- “Did the jerking affect both sides equally, or was one side more involved?”
- “Which way did the eyes or head turn?”
- “Could you get their attention during the episode? Did they respond to you?”
- “Did you notice any color change — blue around the lips or pale?”
- “How long did the shaking last? How long until they were back to normal?”
- “Do you have any video on your phone?” (Invaluable for diagnosis)
4. Physical Examination
A systematic head-to-toe approach for seizure evaluation
Systematic Framework: The physical examination in a patient presenting with seizure serves three purposes: (1) identifying signs of ongoing seizure activity or post-ictal state, (2) detecting the underlying cause, and (3) recognizing complications of the seizure itself. Use a systematic “General → Neurological → Systemic” approach.
General Inspection
- Level of consciousness: Alert, drowsy, confused, obtunded, comatose — post-ictal confusion typically resolves within 30 minutes; prolonged alteration suggests non-convulsive status epilepticus or underlying pathology
- Respiratory pattern: Tachypnea (metabolic acidosis post-seizure), irregular breathing (brainstem dysfunction), stridor (airway compromise)
- Skin: Cyanosis (hypoxia during seizure), diaphoresis, pallor; look for neurocutaneous stigmata (ash-leaf spots, café-au-lait macules, facial angiofibromas)
- Positioning: Decorticate or decerebrate posturing suggests severe brain injury
- Signs of trauma: Head lacerations, facial bruising, shoulder deformity (posterior dislocation)
- Incontinence: Urinary incontinence supports but does not confirm seizure; can occur with syncope
Vital Signs
| Vital Sign | What to Look For | Clinical Significance |
|---|---|---|
| Temperature | Fever (>38°C), hyperthermia (>40°C) | Fever suggests infection (meningitis, encephalitis); hyperthermia occurs in prolonged status epilepticus and is a poor prognostic sign |
| Heart rate | Tachycardia, bradycardia, irregularity | Post-ictal tachycardia is common; ictal bradycardia/asystole can occur and may cause falls (ictal syncope) |
| Blood pressure | Hypertension, hypotension | Severe hypertension: consider posterior reversible encephalopathy syndrome, eclampsia, hypertensive encephalopathy, intracranial hemorrhage. Hypotension: sepsis, medication toxicity |
| Respiratory rate | Tachypnea, apnea, irregular pattern | Post-ictal tachypnea compensates for lactic acidosis; apnea during seizure is common; persistent respiratory depression suggests ongoing seizure or drug effect |
| Oxygen saturation | Desaturation during or after seizure | Transient desaturation common during generalized tonic-clonic seizure; persistent hypoxia requires airway intervention |
| Glucose (point-of-care) | Hypoglycemia (<70 mg/dL), hyperglycemia | Hypoglycemia is a reversible cause — check immediately; hyperglycemia with ketones suggests diabetic ketoacidosis; non-ketotic hyperglycemia can cause focal seizures |
Head and Neck Examination
Head
- Scalp: Lacerations, hematomas, signs of trauma; palpate for skull fractures
- Battle sign: Mastoid ecchymosis — basilar skull fracture
- Raccoon eyes: Periorbital ecchymosis — basilar skull fracture
- Hemotympanum: Blood behind tympanic membrane — basilar skull fracture
- CSF leak: Clear fluid from nose (rhinorrhea) or ear (otorrhea) — skull fracture with dural tear
Neck
- Meningismus: Neck stiffness, Kernig sign, Brudzinski sign — meningitis, subarachnoid hemorrhage
- Carotid bruits: Cerebrovascular disease as cause of stroke-related seizures
- Thyroid: Goiter, thyroidectomy scar — consider hypocalcemia (post-surgical hypoparathyroidism)
- Jugular venous pressure: Elevated in heart failure (may contribute to cerebral hypoperfusion)
- Lymphadenopathy: Malignancy, infection
Oral Cavity Examination
Tongue Bite: Location Matters
- Lateral tongue laceration: Highly specific for generalized tonic-clonic seizure (bitten during tonic phase); look on both sides
- Tip of tongue bite: Non-specific; can occur with syncope or psychogenic events
- Buccal mucosa laceration: Can occur with seizure but less specific
- Gingival hyperplasia: Chronic phenytoin use
- Oral candidiasis: Immunocompromise, recent antibiotic or steroid use
Neurological Examination
Mental Status
- Level of consciousness: Glasgow Coma Scale; document time course of improvement
- Orientation: Person, place, time, situation
- Attention: Digit span, serial 7s, spelling “WORLD” backwards
- Language: Fluency, comprehension, naming, repetition — post-ictal aphasia suggests dominant hemisphere focus
- Memory: Anterograde and retrograde amnesia for the event is expected
- Behavior: Agitation, automatisms (ongoing subtle seizure activity?), psychiatric symptoms (autoimmune encephalitis)
Cranial Nerves
| Cranial Nerve | Key Findings | Significance |
|---|---|---|
| II (Optic) | Visual field defect, papilledema | Homonymous hemianopia suggests structural lesion; papilledema indicates elevated intracranial pressure (tumor, venous thrombosis, idiopathic intracranial hypertension) |
| III, IV, VI (Oculomotor) | Pupil asymmetry, gaze deviation, diplopia | Persistent gaze deviation toward lesion (destructive) or away from lesion (irritative/ictal); dilated unreactive pupil suggests uncal herniation |
| VII (Facial) | Facial asymmetry | Central facial weakness (forehead spared) suggests contralateral hemispheric lesion; may be post-ictal (Todd’s phenomenon) |
| Fundoscopy | Papilledema, retinal hemorrhages | Papilledema: raised intracranial pressure. Subhyaloid hemorrhages: subarachnoid hemorrhage |
Motor Examination
- Tone: Increased tone may indicate upper motor neuron lesion; hypotonia in post-ictal period
- Power: Test all major muscle groups; focal weakness (Todd’s paralysis) is transient and indicates focal seizure origin
- Pronator drift: Sensitive test for subtle upper motor neuron weakness
- Reflexes: Asymmetry suggests structural lesion; hyperreflexia with upgoing plantar response indicates upper motor neuron dysfunction
- Plantar response: Extensor (Babinski sign) may be transiently present post-ictally; persistent upgoing plantar suggests structural lesion
Todd’s Paralysis (Post-ictal Paresis)
Transient focal weakness following a focal seizure, typically lasting minutes to hours (rarely up to 48 hours). It indicates the seizure originated from the contralateral motor cortex. Important: If weakness persists beyond 24-48 hours, strongly consider an acute structural lesion (stroke, tumor) rather than attributing to Todd’s phenomenon.
Sensory and Cerebellar Examination
- Sensory: Hemisensory loss suggests contralateral parietal lesion
- Cerebellar: Ataxia, dysmetria, nystagmus — may indicate posterior fossa lesion, chronic alcohol use, or antiseizure medication toxicity (phenytoin, carbamazepine)
Systemic Examination
Cardiovascular
- Heart sounds: Murmurs may suggest endocarditis (source of embolic stroke) or structural heart disease
- Rhythm: Irregularly irregular pulse suggests atrial fibrillation (stroke risk)
- Peripheral pulses: Asymmetry may indicate vascular disease
- Edema: Heart failure, nephrotic syndrome (may cause cerebral edema or metabolic derangements)
Respiratory
- Aspiration: Focal crackles may indicate aspiration during seizure
- Consolidation: Pneumonia can cause seizures via hypoxia, fever, or sepsis
Abdominal
- Hepatomegaly: Liver disease (hepatic encephalopathy, alcohol abuse)
- Stigmata of chronic liver disease: Spider angiomata, palmar erythema, ascites
- Surgical scars: Transplant (immunosuppression), parathyroidectomy (hypocalcemia)
Skin and Extremities
| Finding | Description | Associated Condition |
|---|---|---|
| Ash-leaf spots | Hypopigmented macules (best seen with Wood lamp) | Tuberous sclerosis complex — cortical tubers cause epilepsy |
| Facial angiofibromas | Red papules on nasolabial folds and cheeks | Tuberous sclerosis complex |
| Shagreen patch | Connective tissue nevus on lower back | Tuberous sclerosis complex |
| Café-au-lait macules | Light brown flat spots (>6 spots or >15 mm is significant) | Neurofibromatosis type 1 — optic gliomas, brain tumors |
| Port-wine stain (facial) | Vascular malformation in trigeminal distribution | Sturge-Weber syndrome — leptomeningeal angioma causes seizures |
| Track marks | Injection sites on arms | Intravenous drug use — infection risk, drug-related seizures |
| Shoulder deformity | Squared-off shoulder, limited external rotation | Posterior shoulder dislocation — classic complication of seizure |
Expected Findings by Etiology
| Condition | General/Vital Signs | Neurological | Other Findings |
|---|---|---|---|
| Post-ictal state (uncomplicated) | Tachycardia, mild hypertension, normal temperature | Confusion improving over minutes; may have Todd’s paralysis; possible lateral tongue bite | Urinary incontinence; muscle soreness |
| Status epilepticus | Tachycardia, hypertension, hyperthermia; may progress to hypotension | Ongoing convulsions or subtle motor activity; may appear comatose (non-convulsive status) | Metabolic acidosis, rhabdomyolysis |
| Structural lesion (tumor, stroke) | Variable; may be normal | Focal neurological deficit (hemiparesis, hemianopia, aphasia); papilledema if mass effect | May have signs of primary cancer |
| Meningitis/Encephalitis | Fever, tachycardia | Meningismus, altered mental status; may have focal signs in encephalitis | Rash (meningococcal); photophobia |
| Alcohol withdrawal | Tachycardia, hypertension, hyperthermia, diaphoresis | Tremor, agitation; may have encephalopathy; usually no focal signs | Stigmata of chronic liver disease |
| Metabolic (hypoglycemia, hyponatremia) | Variable; diaphoresis and tremor with hypoglycemia | Usually non-focal; may have altered consciousness | Signs of underlying cause (diabetes, heart failure) |
| Eclampsia | Severe hypertension, edema | May have visual disturbance, altered mental status | Pregnancy or recent delivery; proteinuria |
| Autoimmune encephalitis | May be normal or have low-grade fever | Psychiatric symptoms, memory impairment, movement disorders (orofacial dyskinesias, dystonia) | May have ovarian teratoma (anti-NMDA receptor encephalitis) |
Important Teaching Point
A normal physical examination is common in epilepsy patients! Many patients with epilepsy, particularly those with genetic generalized epilepsy or temporal lobe epilepsy without hippocampal sclerosis, have entirely normal neurological examinations between seizures. A normal examination does not exclude significant pathology — neuroimaging and electroencephalography are essential components of the workup. However, any focal neurological finding on examination mandates urgent neuroimaging to exclude a structural lesion.
5. Differential Diagnosis
Systematic approach organized by probability and clinical features
The differential diagnosis of seizure involves two parallel considerations: (1) Was this event truly a seizure, or a seizure mimic? and (2) If it was a seizure, what is the underlying cause? The approach differs based on whether this is a first seizure or a breakthrough seizure in a patient with known epilepsy.
First Unprovoked Seizure in Adults: Etiologies
| Probability | Etiology | Key Features | Red Flags |
|---|---|---|---|
| COMMON (approximately 60-70%) | Unknown/Cryptogenic | No identifiable cause after workup; normal MRI and routine EEG | None inherent; important to rule out other causes |
| Remote symptomatic (prior brain injury) | History of stroke, traumatic brain injury, brain surgery; latency of months to years | New focal deficits suggest acute lesion, not remote | |
| Genetic generalized epilepsy | Young adult; morning myoclonus; triggered by sleep deprivation; family history | Onset after age 25 is atypical — consider structural cause | |
| LESS COMMON (approximately 20-30%) | Brain tumor (primary or metastatic) | Progressive headache, focal deficits; seizures in 30-50% of brain tumor patients | New seizure in patient with known cancer; progressive symptoms |
| Cerebrovascular disease | Acute stroke (early seizure within 7 days) or remote stroke; focal onset | New focal deficit, sudden onset | |
| Traumatic brain injury (acute) | Seizure within 7 days of head trauma; higher risk with penetrating injury, hemorrhage | Signs of skull fracture, altered consciousness, focal deficit | |
| Alcohol withdrawal | Seizure 6-48 hours after last drink; history of heavy use; usually generalized tonic-clonic | Autonomic instability, delirium tremens | |
| UNCOMMON BUT SERIOUS (approximately 5-10%) | Central nervous system infection | Meningitis, encephalitis, brain abscess; fever, headache, altered mental status | Fever, meningismus, rapid deterioration |
| Autoimmune encephalitis | Subacute onset; psychiatric symptoms, memory impairment, movement disorders | Refractory seizures, rapid cognitive decline, dyskinesias | |
| Cerebral venous thrombosis | Headache, seizures, focal deficits; risk factors (oral contraceptives, pregnancy, thrombophilia) | Severe headache, papilledema, hemorrhagic infarcts | |
| Posterior reversible encephalopathy syndrome | Severe hypertension, headache, visual disturbance, seizures; eclampsia, immunosuppressants | Severe hypertension, cortical blindness, pregnant/postpartum |
Acute Symptomatic (Provoked) Seizures
Key Distinction: Provoked seizures occur in close temporal relationship with an acute insult and do not constitute epilepsy. Treatment focuses on correcting the underlying cause rather than long-term antiseizure medication.
| Category | Specific Causes | Time Window | Management Focus |
|---|---|---|---|
| Metabolic | Hypoglycemia (<40 mg/dL), hyponatremia (<120 mEq/L or rapid decline), hypocalcemia, hypomagnesemia, uremia, hepatic encephalopathy | During metabolic derangement | Correct metabolic abnormality; short-term antiseizure medication if recurrent |
| Drug/toxin-induced | Cocaine, amphetamines, tramadol, bupropion, isoniazid, fluoroquinolones, theophylline, local anesthetic toxicity | During intoxication | Supportive care, specific antidotes if available (pyridoxine for isoniazid) |
| Withdrawal | Alcohol (6-48 hours), benzodiazepines (2-7 days), barbiturates, baclofen | During withdrawal period | Appropriate taper/substitution; benzodiazepines for alcohol withdrawal |
| Acute structural | Acute stroke (within 7 days), acute traumatic brain injury (within 7 days), intracranial hemorrhage | Within 7 days of insult | Treat underlying condition; consider short-term antiseizure medication for prevention |
| Infectious | Meningitis, encephalitis (especially herpes simplex virus), brain abscess, neurocysticercosis | During acute infection | Antimicrobial therapy; antiseizure medication during acute phase |
| Other | Eclampsia, posterior reversible encephalopathy syndrome, hypertensive encephalopathy | During acute condition | Blood pressure control, delivery in eclampsia, magnesium sulfate |
Breakthrough Seizure in Known Epilepsy
Step-by-Step Approach:
- Step 1: Check medication adherence — missed doses are the most common cause
- Step 2: Review for precipitating factors — sleep deprivation, alcohol, illness, new medications
- Step 3: Check antiseizure medication levels if applicable (phenytoin, carbamazepine, valproate, phenobarbital)
- Step 4: Consider drug interactions — new medications reducing antiseizure medication efficacy
- Step 5: Evaluate for new pathology if no clear precipitant — repeat neuroimaging if indicated
| Cause | Frequency | Key Questions |
|---|---|---|
| Medication non-adherence | Most common | “Have you missed any doses? Had trouble getting your prescription?” |
| Sleep deprivation | Very common | “How many hours have you slept recently?” |
| Alcohol use | Common | “Have you been drinking alcohol? More than usual?” |
| Intercurrent illness | Common | “Have you been sick with fever, vomiting, or diarrhea?” |
| Drug interaction | Less common | “Have you started any new medications, including over-the-counter or supplements?” |
| Subtherapeutic drug level | Less common | Check levels; consider generic substitution, malabsorption |
| Disease progression | Uncommon | Consider repeat imaging if no other explanation; new structural lesion? |
Seizure Mimics: The Critical Differential
| Condition | Approximate Frequency | Key Distinguishing Features |
|---|---|---|
| Syncope (including convulsive syncope) | Most common mimic (up to 20% of “seizure” referrals) | Trigger (prolonged standing, pain); prodrome (lightheadedness, tunnel vision); brief duration (<1 minute); rapid recovery; brief myoclonic jerks may occur |
| Psychogenic non-epileptic seizures (PNES) | 5-20% of epilepsy clinic referrals | Variable, prolonged episodes; asynchronous movements; preserved awareness despite “convulsion”; eyes closed; suggestible; emotional triggers; no post-ictal confusion |
| Transient ischemic attack | Less common | Negative symptoms (weakness, numbness, vision loss) rather than positive symptoms; usually no altered consciousness |
| Migraine with aura | Less common | Visual symptoms evolve slowly over 5-60 minutes; followed by headache; no loss of consciousness |
| Transient global amnesia | Uncommon | Sudden anterograde amnesia lasting hours; repetitive questioning; no other neurological deficits; full recovery |
| Movement disorders | Uncommon | Paroxysmal dyskinesias, tics, myoclonus; preserved consciousness; stereotyped movements |
| Cardiac arrhythmia | Uncommon but serious | Sudden collapse, may have brief convulsive movements; palpitations; family history of sudden death; abnormal ECG |
| Sleep disorders | Uncommon | REM sleep behavior disorder, parasomnia, narcolepsy with cataplexy; events occur during sleep or sleep-wake transitions |
| Hypoglycemia | Uncommon | Diabetic patient; confusion, diaphoresis, tremor; may progress to seizure if untreated |
Anatomical Approach to Seizure Etiology
Cortical/Hemispheric
Brain tumor (primary, metastatic)
Stroke (ischemic, hemorrhagic)
Traumatic brain injury
Cortical dysplasia
Mesial temporal sclerosis
Cavernous malformation
Arteriovenous malformation
Meningeal/Infectious
Bacterial meningitis
Viral encephalitis (herpes simplex virus)
Brain abscess
Neurocysticercosis
Tuberculoma
Fungal infection (immunocompromised)
Leptomeningeal carcinomatosis
Systemic/Metabolic
Hypoglycemia
Hyponatremia
Hypocalcemia, hypomagnesemia
Uremia
Hepatic encephalopathy
Hypoxia
Thyroid storm, myxedema
Toxic/Drug-Related
Alcohol withdrawal
Benzodiazepine/barbiturate withdrawal
Cocaine, amphetamines
Medication toxicity (see drug table)
Organophosphate poisoning
Carbon monoxide poisoning
Heavy metals (lead)
Drug-Induced Seizures
| Drug or Drug Class | Mechanism | Risk Factors | Management Notes |
|---|---|---|---|
| Bupropion | Dose-dependent lowering of seizure threshold; inhibits GABA | Doses >450 mg/day, bulimia, alcohol withdrawal, history of seizures | Contraindicated in patients with seizure history; avoid in eating disorders |
| Tramadol | Lowers seizure threshold; serotonergic effects; inhibits GABA | High doses, concomitant serotonergic drugs, history of epilepsy | Risk increases with dose; avoid in epilepsy patients if possible |
| Fluoroquinolones | GABA-A receptor antagonism | Renal impairment, concurrent NSAIDs, history of seizures | Risk varies by agent; avoid in patients with epilepsy if alternatives exist |
| Carbapenems (imipenem) | GABA antagonism; imipenem has highest risk | Renal impairment, central nervous system pathology, high doses | Meropenem has lower seizure risk; adjust dose for renal function |
| Isoniazid | Depletes pyridoxine (vitamin B6), reducing GABA synthesis | Overdose, chronic use without pyridoxine supplementation, malnutrition | Treat with high-dose pyridoxine (gram-for-gram of isoniazid ingested) |
| Tricyclic antidepressants | Sodium channel blockade (in overdose); anticholinergic effects | Overdose, therapeutic use in susceptible patients | Overdose is medical emergency; sodium bicarbonate for QRS widening |
| Clozapine | Dose-dependent lowering of seizure threshold | Doses >600 mg/day, rapid titration | Seizure risk 3-5% at high doses; consider prophylactic antiseizure medication |
| Theophylline | Adenosine receptor antagonism; stimulant effects | Toxicity (level >20 mcg/mL), drug interactions | Monitor levels; seizures may be refractory and indicate need for hemodialysis |
| Baclofen | Withdrawal of GABA-B agonism causes rebound excitation | Abrupt discontinuation, intrathecal pump malfunction | Never stop abruptly; withdrawal can cause status epilepticus, hyperthermia |
| Cyclosporine/Tacrolimus | Neurotoxicity, posterior reversible encephalopathy syndrome | High levels, hypomagnesemia, hypertension | Check levels and magnesium; may need to reduce dose or switch agents |
Quick Reference: “If You See This, Think This”
| Clinical Clue | Think This First | Next Step |
|---|---|---|
| Young adult, morning myoclonus, triggered by sleep deprivation | Juvenile myoclonic epilepsy | EEG (generalized polyspike-wave); avoid carbamazepine, phenytoin |
| Seizure 24-48 hours after stopping alcohol | Alcohol withdrawal seizure | Benzodiazepines; monitor for delirium tremens; thiamine |
| Fever, headache, confusion, temporal lobe seizures | Herpes simplex encephalitis | Empiric acyclovir immediately; lumbar puncture; MRI brain |
| Pregnant/postpartum with hypertension and seizure | Eclampsia | Magnesium sulfate; blood pressure control; delivery planning |
| Subacute psychiatric symptoms, memory loss, orofacial dyskinesias | Anti-NMDA receptor encephalitis | CSF studies, antibody panel; pelvic imaging (ovarian teratoma); immunotherapy |
| Known cancer patient with new focal seizure | Brain metastases | Contrast MRI brain; consider leptomeningeal disease |
| Recent head trauma with seizure | Acute symptomatic seizure (traumatic) | CT head; short-term antiseizure medication; neurosurgical evaluation if indicated |
| Focal seizure with aura of epigastric rising, déjà vu | Temporal lobe epilepsy | MRI for mesial temporal sclerosis; video-EEG if surgery candidate |
| Brief staring spells with immediate recovery | Absence seizure (or focal seizure with impaired awareness) | EEG to differentiate; 3 Hz spike-wave = absence (generalized) |
| Prolonged event with waxing-waning, eyes closed, no post-ictal confusion | Psychogenic non-epileptic seizure | Video-EEG for definitive diagnosis; psychiatric evaluation; avoid polypharmacy |
6. Diagnostic Investigations
A stepwise, cost-effective approach guided by clinical suspicion
The investigation of seizures aims to: (1) identify reversible causes requiring immediate treatment, (2) classify the seizure type and epilepsy syndrome, (3) determine etiology to guide prognosis and treatment, and (4) assess risk of recurrence. The approach differs for emergency evaluation versus outpatient workup of first seizure versus established epilepsy.
Emergency Department Investigations
Immediate Bedside Tests
- Point-of-care glucose: Check immediately — hypoglycemia is rapidly reversible and life-threatening if missed
- Oxygen saturation: Hypoxia during/after seizure; aspiration risk
- ECG: Arrhythmia as cause (long QT, Brugada) or consequence; QTc prolongation from medications
Baseline Investigations for All Patients with Seizure
| Investigation | Purpose | What to Look For | Practical Points |
|---|---|---|---|
| Serum glucose | Identify hypoglycemia | <70 mg/dL (symptomatic); <40 mg/dL (seizure threshold) | Point-of-care testing; treat immediately if low |
| Serum sodium | Identify hyponatremia | <120 mEq/L or rapid decline >10 mEq/L in 24 hours | Rate of change matters; correct slowly to avoid osmotic demyelination |
| Serum calcium (ionized preferred) | Identify hypocalcemia | Ionized calcium <1.0 mmol/L | Check with magnesium; hypomagnesemia causes refractory hypocalcemia |
| Serum magnesium | Identify hypomagnesemia | <1.5 mg/dL; critical if <1.0 mg/dL | Essential in pregnancy (eclampsia treatment); alcoholism |
| Renal function (BUN, creatinine) | Identify uremia; guide medication dosing | Elevated BUN and creatinine; uremic encephalopathy | Many antiseizure medications require renal dose adjustment |
| Complete blood count | Infection, hematologic abnormality | Leukocytosis (infection), thrombocytopenia (DIC in status epilepticus) | Transient leukocytosis common post-ictally; does not confirm infection |
| Liver function tests | Hepatic encephalopathy; guide medication dosing | Elevated transaminases, low albumin, elevated ammonia | Many antiseizure medications hepatically metabolized |
| Toxicology screen (urine/serum) | Drug intoxication or withdrawal | Cocaine, amphetamines, benzodiazepines, opioids, alcohol | May not detect synthetic drugs; clinical suspicion remains important |
| Blood alcohol level | Intoxication or withdrawal | Level and timing help determine withdrawal risk | Withdrawal seizures typically occur when level is declining or zero |
| Antiseizure medication levels | Therapeutic monitoring in known epilepsy | Subtherapeutic levels; supratherapeutic (toxicity) | Useful for phenytoin, carbamazepine, valproate, phenobarbital; less useful for newer agents |
| Pregnancy test | All women of childbearing age | Pregnancy changes management (eclampsia risk, medication teratogenicity) | Guides medication selection; consider eclampsia if positive |
Neuroimaging
CT Head (Non-contrast)
Indications for Emergent CT
- First seizure in any adult
- New focal neurological deficit
- Persistent altered mental status
- Recent head trauma
- Anticoagulation therapy
- Known malignancy
- Immunocompromised patient
- History of HIV/AIDS
- Fever with suspected central nervous system infection
- Status epilepticus
What CT Can Detect
- Intracranial hemorrhage (acute)
- Large mass lesions
- Acute hydrocephalus
- Major stroke (may be subtle early)
- Skull fractures (trauma)
- Cerebral edema
- Calcified lesions (neurocysticercosis)
CT Limitations
- Misses many structural causes of epilepsy
- Poor visualization of temporal lobes, posterior fossa
- Cannot detect mesial temporal sclerosis
- Small tumors, cavernomas may be missed
MRI Brain (Epilepsy Protocol)
MRI is the Gold Standard for Epilepsy Workup
MRI should be performed in all patients with new-onset epilepsy unless there is a clear, identifiable, and reversible provoked cause. MRI detects structural abnormalities in approximately 25-30% of patients with epilepsy.
| MRI Finding | Description | Associated Condition |
|---|---|---|
| Hippocampal sclerosis | Atrophy and T2/FLAIR hyperintensity of hippocampus | Mesial temporal lobe epilepsy — most common surgically remediable epilepsy |
| Focal cortical dysplasia | Cortical thickening, blurring of gray-white junction, T2/FLAIR signal abnormality | Developmental malformation; often drug-resistant; surgical candidate |
| Cavernous malformation | “Popcorn” lesion with hemosiderin rim on susceptibility-weighted imaging | Vascular malformation; may be multiple; surgical option |
| Brain tumor | Mass with enhancement, surrounding edema, mass effect | Primary (glioma, meningioma) or metastatic |
| Encephalomalacia | Old infarct or traumatic injury; gliosis, volume loss | Remote symptomatic epilepsy (post-stroke, post-traumatic) |
| Temporal lobe encephalitis pattern | T2/FLAIR hyperintensity in medial temporal lobes (may be bilateral) | Herpes simplex encephalitis, autoimmune encephalitis |
| Posterior reversible encephalopathy syndrome pattern | Bilateral parieto-occipital T2/FLAIR hyperintensity | Posterior reversible encephalopathy syndrome (hypertension, eclampsia, immunosuppressants) |
Electroencephalography (EEG)
EEG Purpose: The EEG supports the diagnosis of epilepsy, helps classify seizure type (focal versus generalized), identifies epilepsy syndrome, and guides medication selection. A normal EEG does NOT exclude epilepsy — interictal EEG is normal in up to 50% of patients with epilepsy on a single routine recording.
Types of EEG Studies
| Study Type | Duration | Indication | Yield |
|---|---|---|---|
| Routine EEG | 20-40 minutes | Initial evaluation of suspected epilepsy; post-seizure workup | Detects interictal abnormalities in approximately 30-50% of epilepsy patients |
| Sleep-deprived EEG | 20-40 minutes after sleep deprivation | Increases yield when routine EEG is normal | Increases detection by 20-30%; sleep and sleep deprivation activate epileptiform discharges |
| Ambulatory EEG | 24-72 hours | Capture events; quantify seizure frequency; medication adjustment | Higher yield due to prolonged recording; captures sleep |
| Continuous EEG (cEEG) monitoring | Hours to days (ICU) | Status epilepticus monitoring; altered mental status in critically ill; post-cardiac arrest | Detects non-convulsive seizures in 10-30% of comatose ICU patients |
| Video-EEG monitoring | Days (inpatient) | Seizure characterization; presurgical evaluation; differentiate epileptic versus non-epileptic events | Gold standard for capturing events and correlating semiology with EEG |
Key EEG Findings and Their Significance
| EEG Finding | Description | Clinical Significance |
|---|---|---|
| 3 Hz generalized spike-wave | Rhythmic spike-and-wave complexes at 3 Hz, bilateral synchronous | Childhood/juvenile absence epilepsy; responds to ethosuximide, valproate |
| 4-6 Hz generalized polyspike-wave | Fast spike-wave with polyspikes, generalized | Juvenile myoclonic epilepsy; lifelong treatment usually needed |
| Focal sharp waves or spikes | Epileptiform discharges localized to one region | Focal epilepsy; location helps identify seizure focus |
| Temporal intermittent rhythmic delta activity (TIRDA) | Rhythmic delta activity over temporal region | Highly associated with temporal lobe epilepsy; lateralizing value |
| Periodic lateralized epileptiform discharges (PLEDs/LPDs) | Periodic sharp waves or spikes, lateralized to one hemisphere | Acute destructive lesion (stroke, encephalitis, tumor); high seizure risk |
| Generalized periodic discharges (GPDs) | Periodic discharges synchronous across both hemispheres | Anoxic brain injury, Creutzfeldt-Jakob disease, severe metabolic encephalopathy |
| Electrographic seizure | Rhythmic, evolving pattern with clear onset and offset | Confirms seizure diagnosis; non-convulsive status epilepticus if prolonged without clinical correlate |
Lumbar Puncture
Indications
- Fever with seizure: Rule out meningitis, encephalitis
- Immunocompromised patient: Opportunistic infections
- Suspected autoimmune encephalitis: CSF antibodies, inflammatory markers
- Suspected subarachnoid hemorrhage: If CT negative but clinical suspicion high
- HIV-positive with new seizure: Cryptococcal meningitis, toxoplasmosis workup
- Suspected carcinomatous meningitis: Cytology, flow cytometry
CSF Analysis
- Cell count and differential: Pleocytosis in infection/inflammation
- Protein: Elevated in infection, malignancy, autoimmune
- Glucose: Low in bacterial meningitis, TB, fungal
- Gram stain and culture: Bacterial meningitis
- HSV PCR: Herpes simplex encephalitis (obtain early)
- Autoimmune panel: Anti-NMDA receptor, LGI1, CASPR2, GABA-B antibodies
- Cytology: Leptomeningeal carcinomatosis
- Oligoclonal bands: Multiple sclerosis, other inflammatory conditions
Before Lumbar Puncture
- Obtain CT head if: focal neurological deficit, papilledema, altered consciousness, immunocompromise, or new seizure — to rule out mass lesion/elevated intracranial pressure
- Do not delay antibiotics for lumbar puncture if bacterial meningitis is suspected
- Check coagulation studies and platelet count
Targeted Investigations by Suspected Etiology
If Suspecting Autoimmune Encephalitis
First-Line Tests
- MRI brain: May show T2/FLAIR hyperintensity in medial temporal lobes
- CSF analysis: Lymphocytic pleocytosis, elevated protein, oligoclonal bands
- Serum autoimmune panel: Anti-NMDA receptor, LGI1, CASPR2, GABA-B, AMPA receptor antibodies
- CSF autoimmune panel: Higher sensitivity for some antibodies (anti-NMDA receptor)
Additional Workup
- Pelvic ultrasound/MRI (women): Ovarian teratoma (anti-NMDA receptor encephalitis)
- CT chest/abdomen/pelvis: Occult malignancy (paraneoplastic)
- PET-CT: If conventional imaging negative but paraneoplastic suspected
- EEG: May show extreme delta brush (anti-NMDA receptor), focal slowing
If Suspecting Genetic Epilepsy
Clinical Indications for Genetic Testing
- Early-onset epilepsy (<2 years)
- Developmental delay with epilepsy
- Multiple seizure types
- Family history of epilepsy
- Drug-resistant epilepsy of unknown cause
- Features of specific syndrome (e.g., Dravet syndrome)
Types of Genetic Tests
- Epilepsy gene panel: Tests known epilepsy genes (50-500+ genes)
- Whole exome sequencing: Broader coverage; higher yield in unknown cases
- Chromosomal microarray: Copy number variants
- Single gene testing: If specific syndrome suspected (e.g., SCN1A for Dravet)
Cardiac Evaluation (Rule Out Arrhythmia)
| Test | Indication | What to Look For |
|---|---|---|
| 12-lead ECG | All patients with transient loss of consciousness | Long QT (>470 ms men, >480 ms women), Brugada pattern, Wolff-Parkinson-White, heart block, arrhythmia |
| Holter monitor (24-48 hours) | Suspected arrhythmia; recurrent unexplained events | Paroxysmal arrhythmias, heart rate variability, pauses |
| Event recorder / Implantable loop recorder | Infrequent events; differentiate seizure from arrhythmia | Capture ECG during event; correlate with symptoms |
| Echocardiogram | Suspected structural heart disease | Cardiomyopathy, valvular disease (embolic stroke risk) |
Investigation Summary by Clinical Scenario
| Scenario | Essential Investigations | Consider Adding |
|---|---|---|
| First unprovoked seizure (ED) | Glucose, electrolytes, renal/liver function, CBC, ECG, CT head, toxicology | MRI brain (can be outpatient), EEG (within 24-48 hours if possible) |
| First seizure outpatient workup | MRI brain (epilepsy protocol), EEG (routine, consider sleep-deprived) | Ambulatory EEG if routine normal; cardiac evaluation if syncope possible |
| Breakthrough seizure in known epilepsy | Antiseizure medication levels, basic metabolic panel, toxicology if indicated | Repeat MRI if no recent imaging; review compliance and precipitants first |
| Status epilepticus | Full metabolic panel, antiseizure medication levels, toxicology, CT head, continuous EEG | Lumbar puncture (after CT), MRI when stable, autoimmune panel if refractory |
| Fever and seizure | Blood cultures, lumbar puncture (after CT if indicated), MRI brain | HSV PCR, consider arbovirus panel, autoimmune encephalitis panel |
| Suspected psychogenic non-epileptic seizures | Video-EEG monitoring (gold standard) | Psychological/psychiatric evaluation; MRI and routine EEG to rule out coexisting epilepsy |
EEG Timing Matters
EEG yield is highest within 24-48 hours of a seizure. Post-ictal slowing and epileptiform discharges are more likely to be captured early. If possible, arrange EEG before discharge from the emergency department or within the first 24-48 hours as an outpatient. Delaying EEG by weeks significantly reduces diagnostic yield.
7. Pattern Recognition and Clinical Decision-Making
Practical algorithms and decision pathways
Step 1: Is This Urgent?
| Clinical Scenario | Urgency Level | Immediate Action |
|---|---|---|
| Ongoing convulsive seizure >5 minutes | EMERGENT | Activate status epilepticus protocol; IV benzodiazepine immediately; airway management; call for help |
| Multiple seizures without return to baseline | EMERGENT | Treat as status epilepticus; IV access; benzodiazepine; prepare second-line agents |
| Post-ictal but not awakening (>30 minutes) | EMERGENT | Consider non-convulsive status epilepticus; emergent EEG; CT head if not done |
| Seizure with fever and altered mental status | EMERGENT | Empiric antibiotics and acyclovir; lumbar puncture after CT; blood cultures |
| Seizure in pregnancy/postpartum with hypertension | EMERGENT | IV magnesium sulfate; blood pressure control; obstetric consultation; delivery planning |
| Seizure with new focal neurological deficit | URGENT | Emergent CT head (stroke, hemorrhage, mass); consider stroke code if acute onset |
| First seizure with complete recovery | URGENT | Full workup in ED; CT head; labs; observation; arrange outpatient MRI and EEG |
| Breakthrough seizure in known epilepsy, now at baseline | SEMI-URGENT | Check medication levels; assess for precipitants; adjust medications if needed; may not require ED |
| Witnessed event, uncertain if seizure | ROUTINE | Detailed history from patient and witness; ECG; consider outpatient neurology referral |
Status Epilepticus Treatment Algorithm
Time-Critical Treatment: “Time is Brain”
GABA-A receptors internalize rapidly during prolonged seizures, making benzodiazepines progressively less effective. Treatment should be aggressive and escalated quickly if seizures do not terminate.
| Time | Stage | Treatment | Key Points |
|---|---|---|---|
| 0-5 minutes | Stabilization | ABCs; oxygen; IV access; glucose check; position safely | Protect airway; do not force objects into mouth; time the seizure |
| 5-10 minutes | First-line therapy | Benzodiazepine: IV lorazepam 4 mg (may repeat once) OR IV diazepam 10 mg OR IM midazolam 10 mg | IM midazolam if no IV access; intranasal or buccal routes also effective |
| 10-20 minutes | Second-line therapy | Antiseizure medication loading: IV fosphenytoin 20 mg PE/kg OR IV valproate 40 mg/kg OR IV levetiracetam 60 mg/kg | Choose based on comorbidities; fosphenytoin contraindicated in heart block; valproate avoid in pregnancy/liver disease |
| 20-40 minutes | Second-line therapy (continued) | If seizures persist: give additional second-line agent OR repeat loading dose | Can use second agent from different class; prepare for intubation |
| >40 minutes | Refractory status epilepticus | Anesthetic agents: IV propofol OR IV midazolam infusion OR IV pentobarbital; continuous EEG monitoring | Requires intubation and ICU; goal is burst suppression on EEG; high mortality |
Step 2: First Seizure Decision Pathway
Key Question: Was this seizure provoked or unprovoked?
- Provoked (acute symptomatic): Treat underlying cause; short-term antiseizure medication may be appropriate; long-term treatment usually not indicated
- Unprovoked: Risk of recurrence approximately 40-50%; decision to treat depends on risk factors, patient preferences, and driving/safety implications
| Clinical Scenario | Recurrence Risk | Recommendation |
|---|---|---|
| Provoked seizure (metabolic, drug/alcohol, acute illness) | Low (if cause corrected) | Correct underlying cause; no long-term antiseizure medication; short-term treatment during acute phase may be appropriate |
| First unprovoked seizure, normal MRI and EEG | ~35% | Shared decision-making; treatment optional; discuss driving restrictions, safety |
| First unprovoked seizure with abnormal EEG (epileptiform) | ~60% | Strong consideration for treatment; meets ILAE criteria for epilepsy diagnosis |
| First unprovoked seizure with structural lesion on MRI | ~65-70% | Recommend treatment; high recurrence risk; meets ILAE criteria for epilepsy |
| First seizure occurring during sleep | Higher than wake seizure | Consider treatment; nocturnal seizures increase SUDEP risk |
| Two or more unprovoked seizures | >60% | Treatment recommended; this defines epilepsy |
Step 3: Antiseizure Medication Selection
| Seizure Type | First-Line Options | Avoid | Special Considerations |
|---|---|---|---|
| Focal seizures (with or without secondary generalization) | Levetiracetam, lamotrigine, oxcarbazepine, lacosamide | Ethosuximide (ineffective) | Carbamazepine/oxcarbazepine effective but more drug interactions |
| Generalized tonic-clonic (primary) | Levetiracetam, lamotrigine, valproate | Carbamazepine, oxcarbazepine, phenytoin (may worsen some generalized epilepsies) | Valproate highly effective but teratogenic; avoid in women of childbearing potential |
| Absence seizures | Ethosuximide, valproate, lamotrigine | Carbamazepine, phenytoin, gabapentin (may worsen) | Ethosuximide only treats absence; if concurrent tonic-clonic, use valproate or lamotrigine |
| Juvenile myoclonic epilepsy | Levetiracetam, valproate, lamotrigine | Carbamazepine, phenytoin, gabapentin (may worsen myoclonus) | Usually requires lifelong treatment; high relapse rate if discontinued |
| Unknown seizure type | Levetiracetam, lamotrigine, valproate | Narrow-spectrum agents until type clarified | Broad-spectrum agents safest when classification uncertain |
Special Population Considerations
| Population | Preferred Agents | Avoid or Use Caution | Key Considerations |
|---|---|---|---|
| Women of childbearing potential | Levetiracetam, lamotrigine, oxcarbazepine | Valproate (teratogenic — neural tube defects, cognitive effects) | Preconception counseling; high-dose folic acid; lamotrigine levels drop in pregnancy |
| Elderly | Levetiracetam, lamotrigine, lacosamide | Phenytoin, carbamazepine (drug interactions, bone loss, cognitive effects) | Start low, go slow; watch for drug interactions with polypharmacy |
| Renal impairment | Agents with hepatic metabolism or low renal clearance | Dose-adjust levetiracetam, gabapentin, pregabalin, topiramate | Check package insert for renal dosing; some agents removed by dialysis |
| Hepatic impairment | Levetiracetam, lacosamide, gabapentin (renally cleared) | Valproate (hepatotoxic), carbamazepine, phenytoin | Avoid hepatically metabolized drugs; protein binding altered |
| Patient on multiple medications | Levetiracetam, lacosamide, gabapentin (few interactions) | Phenytoin, carbamazepine, phenobarbital (CYP450 inducers) | Enzyme inducers affect oral contraceptives, anticoagulants, chemotherapy |
“What Do I Do If…” Decision Reference
| Clinical Situation | Immediate Action | Next Step |
|---|---|---|
| Patient seizing in front of me | Note time; protect from injury; position on side; do NOT restrain or put anything in mouth | If >5 minutes or repeated: activate emergency response; give benzodiazepine |
| Seizure stops but patient not waking up | Maintain airway; check glucose; assess for ongoing subtle seizure activity (eye deviation, twitching) | If >20-30 minutes without improvement: consider non-convulsive status; emergent EEG |
| Patient on antiseizure medication has breakthrough seizure | Check medication adherence; check drug levels if applicable; review for precipitants | If compliant with therapeutic levels: consider dose increase or add-on therapy; reassess diagnosis |
| First seizure in patient with known brain tumor | Start antiseizure medication; assess for tumor progression | Brain MRI with contrast; oncology consultation; levetiracetam preferred (few interactions with chemotherapy) |
| Suspected alcohol withdrawal seizure | Benzodiazepines (lorazepam, diazepam, or chlordiazepoxide per protocol); thiamine | Monitor for delirium tremens (24-72 hours); CIWA protocol; supportive care; CT if focal features |
| Pregnant patient with seizure | Left lateral position; magnesium sulfate if eclampsia suspected; check blood pressure | Obstetric consultation; delivery planning if eclampsia; continue safe antiseizure medication |
| Patient wants to stop antiseizure medication | Discuss risks; seizure-free for at least 2 years is minimum; normal EEG and imaging favorable | If appropriate: slow taper over months; counsel about driving, SUDEP risk; monitor closely |
| Patient with epilepsy wants to drive | Review local regulations (seizure-free interval varies by jurisdiction, typically 3-12 months) | Document counseling; some jurisdictions require physician reporting; patient safety paramount |
Troubleshooting Refractory Seizures
When Seizures Are Not Controlled: Ask These Questions
- Is the diagnosis correct? Up to 20% of “refractory epilepsy” is actually psychogenic non-epileptic seizures — consider video-EEG
- Is the patient taking the medication? Non-adherence is the most common cause of breakthrough seizures
- Is the drug level therapeutic? Check levels for phenytoin, carbamazepine, valproate, phenobarbital
- Is the medication appropriate for the seizure type? Carbamazepine can worsen absence and myoclonic seizures
- Are there drug interactions? Enzyme inducers lower levels of concomitant medications
- Are there modifiable triggers? Sleep deprivation, alcohol, stress, missed medications
- Is there a new structural lesion? Consider repeat MRI if not done recently
- Has the patient been evaluated for epilepsy surgery? Focal epilepsy with identifiable lesion may be curable
- Are there autoimmune or metabolic causes? Consider autoimmune encephalitis panel, metabolic workup
When to Refer to Epilepsy Specialist
Indications for Epilepsy Center Referral
- Drug-resistant epilepsy (failed 2 appropriate medications)
- Considering epilepsy surgery evaluation
- Diagnostic uncertainty (seizure versus non-epileptic events)
- Frequent seizures despite treatment
- Pregnancy planning in woman with epilepsy
- Desire to discontinue medications
- Concern for medication side effects
Surgical Evaluation May Be Appropriate If
- Focal epilepsy with identifiable lesion
- Mesial temporal lobe epilepsy (especially with hippocampal sclerosis)
- Failed 2 or more appropriate antiseizure medications
- Seizures significantly impacting quality of life
- Discrete lesion amenable to resection
Note: Surgery can be curative in up to 60-70% of appropriate candidates with temporal lobe epilepsy
8. Clinical Pearls and Pitfalls
Practical wisdom — learn from successes and avoid common mistakes
Must-Know Clinical Pearls
Witness history is gold: The patient often has no memory of the seizure. Always contact a witness and ask if they have smartphone video — this can be diagnostic.
Lateral tongue bite is highly specific: A laceration on the lateral aspect of the tongue strongly suggests generalized tonic-clonic seizure. Tip-of-tongue bites are non-specific and occur in syncope.
Convulsive syncope is common: Brief myoclonic jerks can occur during syncope due to cerebral hypoperfusion. This does not mean the patient has epilepsy — the key is rapid recovery and presence of typical syncope prodrome.
EEG timing matters: EEG yield is highest within 24-48 hours of a seizure. Arrange early EEG whenever possible — a negative EEG weeks later is much less informative.
Normal EEG does not exclude epilepsy: A single routine EEG is normal in up to 50% of patients with epilepsy. If clinical suspicion is high, repeat EEG, sleep-deprived EEG, or ambulatory monitoring may be needed.
Think autoimmune encephalitis in refractory new-onset seizures: Subacute onset with psychiatric symptoms, memory impairment, and movement disorders should prompt autoimmune testing. Early immunotherapy can be disease-modifying.
Alcohol withdrawal seizures cluster: If a patient has one alcohol withdrawal seizure, there is a 25-30% chance of another within 6 hours. Continue monitoring and benzodiazepine prophylaxis.
Pyridoxine for isoniazid seizures: Isoniazid-induced seizures are often refractory to benzodiazepines. Administer pyridoxine (vitamin B6) gram-for-gram of isoniazid ingested (or 5 grams empirically if amount unknown).
Critical Pitfalls to Avoid
Do not diagnose epilepsy based on a single provoked seizure: Seizures due to hypoglycemia, hyponatremia, drug toxicity, or alcohol withdrawal do not constitute epilepsy and generally do not require long-term antiseizure medication.
Do not delay benzodiazepines in status epilepticus: Every minute of ongoing seizure activity causes progressive neuronal injury and treatment resistance. Give benzodiazepines immediately when seizure exceeds 5 minutes.
Do not assume prolonged post-ictal state is normal: If altered consciousness persists beyond 30 minutes, strongly consider non-convulsive status epilepticus and obtain emergent EEG.
Do not attribute all seizures to epilepsy without excluding mimics: Syncope (including convulsive syncope) and psychogenic non-epileptic seizures are commonly misdiagnosed as epilepsy. Video-EEG is the gold standard when diagnosis is uncertain.
Do not use carbamazepine, phenytoin, or oxcarbazepine for genetic generalized epilepsies: These sodium channel blockers can worsen absence and myoclonic seizures. Use broad-spectrum agents (levetiracetam, valproate, lamotrigine) when generalized epilepsy is suspected.
Do not prescribe valproate to women of childbearing potential without counseling: Valproate is highly teratogenic (neural tube defects, cognitive impairment) and should be avoided when alternatives exist. Document risk discussion.
Do not stop antiseizure medications abruptly: Sudden discontinuation can precipitate status epilepticus, even in patients who may not truly have epilepsy. Always taper gradually.
Do not attribute persistent focal deficit solely to Todd’s paralysis: While Todd’s paralysis is real, it should resolve within 24-48 hours. Persistent focal deficit requires urgent imaging to exclude stroke or other structural lesion.
Key Takeaways
- Differentiate seizure from mimics first: Syncope (with or without convulsive movements), psychogenic non-epileptic seizures, and cardiac arrhythmias are commonly mistaken for epileptic seizures.
- Provoked versus unprovoked determines management: Provoked seizures require treatment of the underlying cause; unprovoked seizures may require long-term antiseizure medication.
- Status epilepticus is a medical emergency: Mortality is 15-22% in adults. Treatment must be rapid and escalating — benzodiazepines first, then antiseizure medication loading, then anesthetics if refractory.
- MRI is essential for all new-onset epilepsy: CT is inadequate for detecting many epilepsy etiologies. MRI with epilepsy protocol should be performed in all patients without a clear provoked cause.
- EEG supports but does not make the diagnosis: Clinical history remains paramount. A normal EEG does not exclude epilepsy; an abnormal EEG in isolation does not confirm it.
- Medication selection should be individualized: Consider seizure type, epilepsy syndrome, comorbidities, childbearing potential, and drug interaction profile.
- Drug-resistant epilepsy requires specialist evaluation: Approximately 30% of patients will not achieve seizure freedom with medications. Early referral for surgical evaluation can be life-changing.
- SUDEP (sudden unexpected death in epilepsy) is a real risk: Occurs in approximately 1 per 1,000 patient-years. Risk factors include uncontrolled generalized tonic-clonic seizures, nocturnal seizures, and polytherapy.
- Driving and safety counseling is essential: Document discussion of driving restrictions, SUDEP risk, safety precautions (swimming, heights, bathing), and pregnancy planning.
- Consider autoimmune encephalitis in new-onset refractory seizures: Treatable cause that requires high index of suspicion. Look for psychiatric symptoms, memory impairment, and movement disorders.
Quick Reference Algorithm
Systematic Approach to Seizure:
- Stabilize: ABCs, protect from injury, check glucose, time the seizure — if ongoing >5 minutes, treat as status epilepticus
- Characterize the event: Obtain detailed history from patient and witnesses — was this truly a seizure? What type?
- Identify the cause: Provoked (metabolic, toxic, structural) versus unprovoked? Check labs, imaging, consider EEG
- Assess urgency: Red flags requiring immediate action? New focal deficit? Signs of infection? Ongoing seizure activity?
- Determine if treatment is indicated: Single provoked seizure — treat cause. Two unprovoked seizures or high-risk first seizure — consider long-term antiseizure medication
- Select appropriate medication: Match to seizure type, epilepsy syndrome, patient factors, and comorbidities
- Counsel on safety: Driving restrictions, SUDEP, safety precautions, medication adherence, when to seek emergency care
- Arrange follow-up: Outpatient neurology, MRI if not done, EEG if not done, reassess treatment response