Clinical Approach to Seizure

Comprehensive Practical Framework

1
Symptom Overview
Overview
2
Pathophysiology
Mechanism
3
History Taking
History
4
Physical Examination
Examination
5
Differential Diagnosis
Differential
6
Investigations
Workup
7
Clinical Decision-Making
Algorithm
8
Pearls and Pitfalls
Summary

1. Symptom Overview

Understanding the clinical significance and classification of seizures

Seizures represent one of the most common neurological emergencies encountered in primary care and emergency settings. Approximately 8 to 10 percent of the general population will experience at least one seizure during their lifetime, with the highest incidence occurring in children under 1 year of age and adults over 55 years. A first unprovoked seizure occurs in approximately 50 per 100,000 persons annually. In the family medicine setting, distinguishing a true seizure from seizure mimics, identifying the underlying cause, and determining which patients require urgent referral are critical skills that directly impact patient outcomes.

Definition

A seizure is a transient occurrence of signs and symptoms resulting from abnormal, excessive, or synchronous neuronal activity in the brain. A convulsion specifically refers to a seizure with prominent motor manifestations (rhythmic jerking movements). Epilepsy is defined as two or more unprovoked seizures occurring more than 24 hours apart, OR one unprovoked seizure with a high probability of recurrence (greater than 60% over the next 10 years), OR diagnosis of an epilepsy syndrome.

Classification by Seizure Type (ILAE 2017)

The International League Against Epilepsy (ILAE) classification system organizes seizures based on where they originate in the brain and the level of awareness during the event.

Category	Subcategory	Key Features	Clinical Significance
Focal Onset	Aware (simple partial)	Consciousness preserved; motor, sensory, autonomic, or psychic symptoms depending on cortical location	May serve as warning (aura) before generalization; localizing value for lesion
	Impaired awareness (complex partial)	Altered consciousness; automatisms (lip smacking, picking at clothes); postictal confusion	Often temporal lobe origin; commonly mistaken for behavioral episodes
	Focal to bilateral tonic-clonic	Begins focally then spreads to both hemispheres; convulsive activity	Witness may only see generalized phase; focal onset suggests structural lesion
Generalized Onset	Tonic-clonic (grand mal)	Loss of consciousness; tonic stiffening followed by clonic jerking; postictal confusion	Most recognized seizure type; high injury risk
	Absence (petit mal)	Brief staring spells (5-30 seconds); abrupt onset and offset; no postictal confusion	Commonly misdiagnosed as inattention; typical in childhood
	Myoclonic	Brief, shock-like jerks of a muscle or muscle group; usually bilateral	May occur in clusters; often upon awakening; seen in juvenile myoclonic epilepsy
Unknown Onset	Unwitnessed or unclear	Insufficient information to classify as focal or generalized	Reclassify when more information becomes available

Classification by Etiology

Provoked (Acute Symptomatic) Seizures

Occur in close temporal relationship to an acute central nervous system insult or systemic condition. The seizure threshold is temporarily lowered by a reversible factor.

Common causes: Metabolic derangements (hypoglycemia, hyponatremia, hypocalcemia), drug intoxication or withdrawal, alcohol withdrawal, acute stroke, traumatic brain injury, central nervous system infections, fever (in children).

Clinical significance: Lower risk of recurrence once the provoking factor is corrected. Antiseizure medication may not be required long-term.

Unprovoked Seizures

Occur in the absence of an identifiable acute precipitant. May be the first presentation of epilepsy or result from a remote brain insult.

Categories: Idiopathic/genetic (no identifiable structural cause), structural (prior stroke, tumor, traumatic brain injury, cortical malformation), unknown cause.

Clinical significance: Higher risk of recurrence (approximately 40-50% after first unprovoked seizure). Requires consideration of long-term antiseizure medication.

Classification by Duration and Pattern

Pattern	Duration	Clinical Features	Urgency
Self-limited seizure	Less than 5 minutes	Spontaneous termination; postictal period; full recovery	Urgent evaluation but not emergency if resolved
Prolonged seizure	5 to 30 minutes	Requires pharmacological intervention to terminate	Emergency — administer benzodiazepine
Status epilepticus	Greater than 5 minutes continuous seizure activity OR 2 or more seizures without return to baseline	Risk of permanent neuronal injury; systemic complications; mortality 10-20%	Medical emergency — immediate intervention required
Cluster seizures	Multiple seizures within 24 hours with recovery between	Patient returns to baseline between events; may progress to status	Urgent — risk of progression

Classification by Timing and Triggers

Timing/Trigger	Description	Suggests
Sleep-related	Occurs primarily during sleep or upon awakening	Frontal lobe epilepsy; juvenile myoclonic epilepsy; benign rolandic epilepsy
Upon awakening	Within 2 hours of waking from sleep	Juvenile myoclonic epilepsy; idiopathic generalized epilepsy
Reflex seizures	Triggered by specific stimuli (flashing lights, reading, music)	Photosensitive epilepsy; reading epilepsy
Catamenial	Seizure clustering around menstruation	Hormonal influence on seizure threshold; consider hormonal adjunct therapy
Stress or sleep deprivation	Increased frequency with poor sleep, illness, or emotional stress	Common trigger in all epilepsy types; lifestyle modification important

Key Concept: The Critical First Question

When evaluating a patient with a new seizure, the most important initial distinction is: Was this a seizure, or a seizure mimic? Up to 20-30% of patients referred to epilepsy centers are ultimately found to have psychogenic nonepileptic seizures (PNES) or other conditions mimicking seizures (syncope, transient ischemic attack, movement disorders). A detailed history from the patient AND a witness is essential.

Risk of Recurrence After First Unprovoked Seizure

Understanding Recurrence Risk

Overall risk of recurrence after a first unprovoked seizure is approximately 40-50% within 2 years. Factors that INCREASE recurrence risk include:

Abnormal electroencephalogram (EEG): Epileptiform discharges double the recurrence risk
Structural brain lesion: Prior stroke, tumor, traumatic brain injury, cortical dysplasia
Nocturnal seizure: Seizure occurring during sleep
Focal neurological deficit: Todd’s paralysis or other postictal deficits
Family history of epilepsy

If recurrence risk exceeds 60%, the patient meets criteria for epilepsy diagnosis after a single seizure.

2. Pathophysiology and Mechanisms

Understanding the underlying mechanisms of seizures

Seizures result from an imbalance between excitatory and inhibitory neurotransmission in the brain, leading to abnormal, hypersynchronous neuronal firing. Understanding the underlying mechanisms helps explain why certain conditions provoke seizures and guides treatment selection. The brain normally maintains a delicate balance between excitation (primarily mediated by glutamate) and inhibition (primarily mediated by gamma-aminobutyric acid, or GABA). Any factor that tips this balance toward excessive excitation can lower the seizure threshold.

The Neuronal Basis of Seizures

Component	Normal Function	Role in Seizure Generation
Excitatory neurotransmission (Glutamate)	Primary excitatory neurotransmitter; activates NMDA and AMPA receptors; allows sodium and calcium influx	Excessive glutamate release or receptor hypersensitivity leads to neuronal hyperexcitability
Inhibitory neurotransmission (GABA)	Primary inhibitory neurotransmitter; opens chloride channels; hyperpolarizes neurons	Reduced GABA synthesis, release, or receptor function decreases inhibitory tone
Voltage-gated ion channels	Sodium, potassium, and calcium channels regulate neuronal excitability and action potential propagation	Channelopathies (genetic or acquired dysfunction) alter neuronal firing patterns
Astrocytes and glia	Regulate extracellular ion concentrations; clear excess glutamate; maintain blood-brain barrier	Glial dysfunction impairs ion homeostasis and neurotransmitter clearance
Cortical interneurons	Provide feedback and feedforward inhibition; synchronize cortical activity	Loss of interneuron function (as in certain genetic epilepsies) leads to hypersynchrony

Ion Channel Mechanisms and Drug Targets

Sodium Channels

Normal function: Rapid depolarization during action potential; inactivate quickly to allow repolarization

In seizures: Persistent sodium channel activation leads to repetitive firing

Drug targets: Phenytoin, carbamazepine, lamotrigine, lacosamide block sodium channels in their inactivated state

Calcium Channels

Normal function: T-type calcium channels generate low-threshold spikes in thalamic neurons; important for sleep rhythms

In seizures: Abnormal T-type channel activity underlies the 3 Hz spike-wave pattern of absence seizures

Drug targets: Ethosuximide blocks T-type calcium channels; first-line for absence seizures

GABA Receptors

Normal function: GABA-A receptors open chloride channels, hyperpolarizing neurons and reducing excitability

In seizures: Reduced GABA-ergic inhibition removes the “brake” on neuronal firing

Drug targets: Benzodiazepines and barbiturates enhance GABA-A receptor activity; valproate increases GABA synthesis

Phases of a Generalized Tonic-Clonic Seizure

Phase	Duration	Clinical Features	Underlying Mechanism
Prodrome (optional)	Hours to days before	Mood changes, irritability, headache — not present in all patients	Unclear; possibly related to building cortical excitability
Aura (if focal onset)	Seconds to minutes	Subjective warning symptoms: rising epigastric sensation, déjà vu, fear, visual or olfactory hallucinations	Focal seizure activity in eloquent cortex before secondary generalization
Tonic phase	10-20 seconds	Sudden loss of consciousness; generalized stiffening; “epileptic cry” (forced expiration through closed glottis); falls; may bite tongue	Massive synchronous depolarization of cortical neurons; sustained muscle contraction
Clonic phase	30-60 seconds	Rhythmic jerking of all extremities; frequency decreases as phase progresses; drooling; cyanosis	Alternating excitation and inhibition; gradual GABA-mediated dampening
Postictal phase	Minutes to hours	Confusion, fatigue, headache, muscle soreness; may have transient focal deficits (Todd’s paralysis)	Neuronal exhaustion; active inhibition; metabolic recovery; cerebral edema in some cases

How Clinical Conditions Lower the Seizure Threshold

Condition	Mechanism	Clinical Implication
Hypoglycemia	Glucose is the brain’s primary energy substrate; deprivation impairs the sodium-potassium ATPase pump, leading to membrane instability	Always check glucose immediately; seizure resolves with glucose correction
Hyponatremia	Decreased extracellular sodium reduces the threshold for action potential generation; cerebral edema in severe cases	Rapid correction can cause osmotic demyelination; correct sodium slowly unless actively seizing
Hypocalcemia	Low extracellular calcium increases neuronal membrane excitability by altering voltage-gated channel behavior	Look for other signs: tetany, Chvostek sign, prolonged QT interval
Alcohol withdrawal	Chronic alcohol upregulates NMDA glutamate receptors and downregulates GABA receptors; removal of alcohol leads to unopposed excitation	Seizures typically occur 6-48 hours after last drink; peak risk of delirium tremens at 48-72 hours
Benzodiazepine or barbiturate withdrawal	Similar to alcohol: chronic use downregulates GABA receptors; abrupt cessation removes inhibitory tone	Potentially life-threatening; requires supervised taper
Drug intoxication (stimulants, tramadol, bupropion)	Stimulants increase catecholamines and glutamate; some drugs lower seizure threshold by blocking sodium channels or GABA	Obtain urine drug screen; specific antidotes may be available
Acute stroke	Ischemia releases glutamate; ion pump failure leads to cytotoxic edema; cortical irritation from hemorrhage	Early seizures (within 7 days) are provoked; late seizures suggest post-stroke epilepsy
Traumatic brain injury	Direct neuronal damage; hemorrhage; inflammation; scarring (gliosis) creates epileptogenic focus	Early post-traumatic seizures (within 7 days) differ from late (post-traumatic epilepsy)
Central nervous system infection	Inflammation; direct neuronal invasion; fever; metabolic derangements; blood-brain barrier disruption	Herpes simplex encephalitis has predilection for temporal lobes; high seizure risk
Brain tumor	Mass effect; disruption of normal cortical architecture; peritumoral edema; metabolic changes	Seizures may be presenting symptom; low-grade tumors often more epileptogenic than high-grade
Eclampsia	Endothelial dysfunction; vasospasm; posterior reversible encephalopathy syndrome (PRES)	Magnesium sulfate is treatment of choice (blocks NMDA receptors)

Genetic Mechanisms in Epilepsy

Channelopathies

Mutations in genes encoding ion channels are the most common identified cause of genetic epilepsy. Examples include:

SCN1A mutations: Sodium channel dysfunction; Dravet syndrome; severe myoclonic epilepsy of infancy
KCNQ2/3 mutations: Potassium channel dysfunction; benign familial neonatal seizures
CACNA1A mutations: Calcium channel dysfunction; associated with absence epilepsy and episodic ataxia

Idiopathic Generalized Epilepsies

Polygenic inheritance with complex genetics. The brain is structurally normal, but there is an inherited predisposition to seizures. Examples include:

Childhood absence epilepsy: Peak onset age 4-8 years; typical 3 Hz spike-wave on EEG
Juvenile myoclonic epilepsy: Onset in adolescence; myoclonic jerks upon awakening; lifelong treatment usually required
Juvenile absence epilepsy: Later onset than childhood form; higher risk of generalized tonic-clonic seizures

Often Overlooked Mechanism: The Role of Sleep Deprivation

Sleep deprivation is one of the most potent and underappreciated seizure triggers. During sleep, the brain undergoes restorative processes that maintain the excitation-inhibition balance. Sleep deprivation leads to:

Increased cortical excitability (demonstrated by transcranial magnetic stimulation studies)
Impaired GABA-mediated inhibition
Increased interictal epileptiform discharges on EEG

Clinical tip: Always ask about sleep patterns in patients with new or breakthrough seizures. In juvenile myoclonic epilepsy, sleep deprivation alone can precipitate seizures in otherwise well-controlled patients.

Pathophysiology of Status Epilepticus: Time-Dependent Changes

Why Prolonged Seizures Are Dangerous

As seizures continue, several time-dependent pathophysiological changes occur that make termination progressively more difficult:

0-5 minutes: GABA-A receptors internalize (move from membrane into cell), reducing benzodiazepine efficacy
5-30 minutes: NMDA glutamate receptors traffic to the cell surface, increasing excitatory tone
30+ minutes: Excitotoxic neuronal injury begins; systemic complications develop (hyperthermia, acidosis, rhabdomyolysis)

Clinical implication: Early benzodiazepine administration (within 5 minutes) is critical. Delayed treatment reduces benzodiazepine effectiveness and increases the need for second-line agents.

3. History Taking

A comprehensive approach to eliciting the seizure history

Red Flags — Require Urgent Evaluation

Prolonged seizure (greater than 5 minutes) — Status epilepticus; immediate intervention required
Multiple seizures without recovery — Impending or established status epilepticus
Fever with seizure in adult — Central nervous system infection (meningitis, encephalitis)
New focal neurological deficit — Stroke, mass lesion, Todd’s paralysis
Severe headache before or after seizure — Subarachnoid hemorrhage, intracranial hemorrhage, venous sinus thrombosis

Seizure following head trauma — Intracranial hemorrhage, traumatic brain injury
First seizure in pregnancy or postpartum — Eclampsia, cerebral venous thrombosis, posterior reversible encephalopathy syndrome
Immunocompromised patient — Opportunistic central nervous system infection, lymphoma
Known malignancy — Brain metastases, paraneoplastic syndrome, metabolic complications
Anticoagulation use — Intracranial hemorrhage risk

The history is the cornerstone of seizure evaluation. Since most patients do not seize in front of a clinician, diagnosis relies heavily on a detailed account from both the patient AND any witnesses. The goals are to: (1) confirm whether the event was truly a seizure, (2) classify the seizure type, (3) identify potential causes or triggers, and (4) assess the risk of recurrence.

Systematic History: The “SEIZE” Approach

Use the mnemonic “SEIZE” to ensure comprehensive history taking for a new seizure:

S — Setting and Start: Where were they? What were they doing? Was there any warning (aura)? How did it begin — suddenly or gradually? Was onset witnessed?
E — Event Description: What exactly happened? Body movements (stiffening, jerking, one side versus both)? Eyes (open, deviated, rolled back)? Sounds (cry, grunting)? Color change? Incontinence? Tongue biting?
I — Ictal Duration and Interval: How long did it last? (Witnesses often overestimate) Was there more than one event? Time between events? Did they return to normal between episodes?
Z — Zone of Recovery (Postictal): What happened afterward? Confusion (how long)? Sleepiness? Headache? Weakness on one side? Able to speak normally? Memory of the event?
E — Etiology Clues: Any provoking factors? Recent illness, sleep deprivation, alcohol or drug use, medication changes, missed doses? Prior seizures or neurological history? Family history of seizures?

Key Questions: Seizure Versus Seizure Mimics

Up to 20-30% of patients referred for “seizures” have an alternative diagnosis. The following features help distinguish true seizures from common mimics:

Feature	True Seizure	Syncope	Psychogenic Nonepileptic Seizure
Trigger or warning	Aura (rising sensation, déjà vu, fear); may occur without warning	Prodrome: lightheadedness, warmth, tunnel vision, nausea; often positional	Often emotional trigger; may occur in presence of others
Duration	Usually 30 seconds to 2 minutes	Brief (less than 30 seconds of unconsciousness)	Often prolonged (many minutes to hours); waxing and waning
Motor activity	Tonic-clonic: rhythmic, synchronous; frequency decreases over time	Brief myoclonic jerks possible (convulsive syncope); arrhythmic	Asynchronous; side-to-side head movement; pelvic thrusting; eyes closed
Eyes during event	Open; may be deviated to one side	Open or closed; eyes may roll up briefly	Often tightly closed; resist passive opening
Tongue biting	Lateral tongue biting highly specific for seizure	Tip of tongue bite may occur	Rare; if present, usually tip of tongue
Incontinence	Common (urinary more than fecal)	May occur	Less common; may occur
Postictal state	Prolonged confusion (minutes to hours); sleepiness; headache; muscle soreness	Rapid recovery (seconds to minutes); may feel nauseated or tired	Variable; may be alert immediately or appear unresponsive; often rapid fluctuation
Recall of event	No memory of ictal period; may recall aura	May recall prodrome; amnesia for period of unconsciousness	Variable; some patients describe awareness during event
Injury	Common (falls, burns, tongue laceration)	May occur from fall	Less common; self-protective movements often preserved

Clinical Pearl: Lateral Tongue Biting

Lateral tongue biting (on the side of the tongue) is highly specific for generalized tonic-clonic seizures and is one of the most reliable features distinguishing true seizures from syncope or psychogenic events. Ask specifically: “Did you bite your tongue? Can you show me where?” The sensitivity is low (approximately 20-30%), but specificity exceeds 95%.

Targeted Questions by Suspected Cause

Suspected Cause	Key Features	Ask This Question
Alcohol withdrawal	Seizure 6-48 hours after last drink; tremor; autonomic instability	“When was your last alcoholic drink? How much do you typically drink per day? Have you had withdrawal seizures before?”
Hypoglycemia	Diabetic patient; missed meal; excess insulin; adrenergic symptoms before seizure	“Are you diabetic? Did you take your insulin? When did you last eat? Did you feel shaky or sweaty beforehand?”
Drug intoxication or toxicity	Recent overdose; stimulant use; medication changes; suicidal ideation	“Have you taken any recreational drugs? Started any new medications? Taken more than prescribed of any medication?”
Medication withdrawal	Recent discontinuation of benzodiazepines, barbiturates, or antiseizure medications	“Have you stopped or missed any medications recently? Any sleeping pills or anxiety medications?”
Central nervous system infection	Fever; headache; neck stiffness; altered mental status; rash	“Have you had fever? Severe headache? Stiff neck? Confusion before the seizure? Any recent travel or sick contacts?”
Stroke	Sudden focal deficits; vascular risk factors; older patient	“Did you notice any weakness, numbness, or speech problems before or after? Do you have high blood pressure, diabetes, or heart problems?”
Brain tumor	Progressive headaches; focal deficits; personality change; weight loss	“Have you had worsening headaches? Any weakness or numbness? Changes in vision, personality, or memory? Unintentional weight loss?”
Eclampsia	Pregnant or recently postpartum; hypertension; edema; visual changes	“Are you pregnant or have you recently delivered? Have you had headaches, swelling, or vision changes? Do you know your blood pressure?”
Sleep deprivation	Inadequate sleep; shift work; new parent; examinations	“How much sleep have you been getting? Have you been staying up late or working night shifts? Any recent changes in sleep pattern?”
Idiopathic generalized epilepsy	Adolescent or young adult; seizures upon awakening; myoclonic jerks; family history	“Do you ever have sudden jerking movements, especially in the morning? Does anyone in your family have seizures or epilepsy?”
Temporal lobe epilepsy	Aura (rising sensation, déjà vu, fear); automatisms; history of febrile seizures	“Do you get a warning before seizures — like a strange feeling in your stomach, or a feeling you’ve experienced this before? Did you have seizures with fevers as a child?”

Essential Witness Questions

The witness history is often more valuable than the patient history. If a witness is available (in person or by phone), ask these specific questions:

“What was the patient doing immediately before the event?”
“Did they say anything or make any sound at the start?”
“What did their body do? Did they stiffen, then shake? One side or both sides?”
“What did their eyes do? Were they open? Looking to one side?”
“Did they change color — pale, blue, or flushed?”
“How long did it last?” (Ask them to demonstrate with a clock if possible — witnesses commonly overestimate)
“What happened when it stopped? How long until they were back to normal?”
“Have you ever seen them do this before?”

Medication and Substance History

Medications That Can CAUSE Seizures

Antidepressants: Bupropion (dose-dependent), tricyclic antidepressants (in overdose), venlafaxine
Antipsychotics: Clozapine (highest risk), chlorpromazine, olanzapine
Analgesics: Tramadol, meperidine (normeperidine metabolite)
Antibiotics: Carbapenems (imipenem highest risk), fluoroquinolones, isoniazid (pyridoxine deficiency)
Immunosuppressants: Cyclosporine, tacrolimus (posterior reversible encephalopathy syndrome)
Stimulants: Cocaine, amphetamines, synthetic cathinones
Others: Theophylline, lithium (toxicity), baclofen withdrawal

Substances and Withdrawal States

Alcohol withdrawal: Peak risk 6-48 hours after cessation; especially if heavy, prolonged use
Benzodiazepine withdrawal: Can occur even with prescribed use; potentially life-threatening
Barbiturate withdrawal: Similar to alcohol; severe withdrawal syndrome
Gamma-hydroxybutyrate (GHB) withdrawal: Increasingly recognized; severe autonomic instability
Stimulant intoxication: Cocaine, methamphetamine, synthetic cathinones
Synthetic cannabinoids: Unpredictable effects; seizures reported
Opioid withdrawal: Seizures are rare in pure opioid withdrawal but may occur with mixed substances

Past Medical and Family History

Relevant Past Medical History

Previous seizures or epilepsy diagnosis
Head trauma (even remote — years prior)
Stroke or transient ischemic attack
Brain surgery or brain tumor
Meningitis or encephalitis
Febrile seizures in childhood
Developmental delay or intellectual disability
Psychiatric history (increased PNES risk)
Diabetes mellitus (hypoglycemia risk)
Chronic kidney disease (uremia, electrolyte disturbances)
Liver disease (hepatic encephalopathy, coagulopathy)
HIV or immunocompromised state
Malignancy (metastases, paraneoplastic syndromes)

Family History

Family history is particularly relevant in patients presenting with a first seizure in adolescence or young adulthood:

Epilepsy or seizure disorder
Febrile seizures
Sudden unexplained death (possible SUDEP in undiagnosed epilepsy)
Neurological disorders (neurodegenerative diseases, tuberous sclerosis, neurofibromatosis)
Psychiatric disorders (may suggest PNES)

Note: A positive family history of epilepsy increases recurrence risk after a first unprovoked seizure and may support the diagnosis of an idiopathic generalized epilepsy syndrome.

Social and Occupational History

Why Social History Matters in Seizure

Social history identifies both potential causes and important safety considerations for counseling:

Alcohol use: Quantify intake (CAGE questionnaire); assess withdrawal risk; heavy use is both a trigger and complicates management
Recreational drug use: Cocaine, amphetamines, synthetic drugs; urine drug screen indicated
Sleep patterns: Shift work, new parent, student with irregular schedule — sleep deprivation is a major trigger
Occupation: Driving, operating heavy machinery, working at heights, healthcare worker — affects counseling about activity restrictions
Living situation: Lives alone versus with others (safety monitoring); access to bathtub (drowning risk)
Pregnancy status: Affects imaging, medication choices, and urgency of evaluation

4. Physical Examination

A systematic head-to-toe approach for patients presenting with seizure

Examination Goals: The physical examination in a patient with new seizure aims to: (1) identify evidence that a seizure occurred (tongue bite, injury), (2) detect signs of an underlying cause (infection, metabolic derangement, structural lesion), (3) assess current neurological status (postictal state, focal deficits), and (4) identify conditions that may mimic seizure (cardiac disease, hypoglycemia).

General Inspection

Level of consciousness: Alert, confused, drowsy, obtunded — postictal confusion typically resolves within 30-60 minutes; prolonged confusion suggests status epilepticus, nonconvulsive seizures, or underlying brain pathology
Respiratory pattern: Tachypnea (metabolic acidosis from prolonged seizure), Cheyne-Stokes (bilateral hemispheric or brainstem dysfunction), agonal breathing (ongoing seizure or severe brain injury)
Signs of injury: Bruises, lacerations, shoulder dislocation (posterior dislocation classic for seizure), scalp hematoma, facial trauma
Incontinence: Wet clothing, urine odor — supports diagnosis of generalized seizure but not specific
Signs of substance use: Track marks, alcohol on breath, dilated or constricted pupils, diaphoresis
Medic alert jewelry: Check for epilepsy, diabetes, or other relevant conditions

Vital Signs

Vital Sign	What to Look For	Clinical Significance
Temperature	Fever (greater than 38°C / 100.4°F); hypothermia	Fever: central nervous system infection, sepsis, prolonged seizure-induced hyperthermia. Hypothermia: environmental exposure, hypothyroidism, sepsis
Heart Rate	Tachycardia; bradycardia; irregular rhythm	Tachycardia: postictal, fever, substance use, withdrawal. Bradycardia: increased intracranial pressure, cardiac arrhythmia as seizure mimic. Irregular: atrial fibrillation (stroke risk)
Blood Pressure	Hypertension; hypotension	Severe hypertension: eclampsia, posterior reversible encephalopathy syndrome, hypertensive encephalopathy, autonomic instability in withdrawal. Hypotension: sepsis, postictal, cardiac cause
Respiratory Rate	Tachypnea; bradypnea; apnea	Tachypnea: compensation for lactic acidosis after prolonged seizure. Bradypnea/apnea: ongoing nonconvulsive seizure, medication effect, increased intracranial pressure
Oxygen Saturation	Hypoxia (less than 94%)	May persist postictally; consider aspiration, ongoing subtle seizure, pulmonary edema (neurogenic or cardiac)
Blood Glucose	Hypoglycemia (less than 70 mg/dL); hyperglycemia	Hypoglycemia is immediately treatable cause of seizure. Hyperglycemia: diabetic ketoacidosis, hyperosmolar state (nonketotic hyperglycemia can cause focal seizures)

Check Glucose Immediately

Point-of-care glucose should be checked in ALL patients presenting with seizure or altered mental status. Hypoglycemia is a rapidly reversible cause of seizures, and delayed recognition can lead to permanent neurological injury. Do not wait for laboratory results — use bedside glucometer.

Head and Neck Examination

Head

Scalp: Lacerations, hematomas, signs of trauma — may indicate fall during seizure or raise concern for traumatic cause
Battle sign: Mastoid ecchymosis — basilar skull fracture
Raccoon eyes: Periorbital ecchymosis — basilar skull fracture
Hemotympanum: Blood behind tympanic membrane — basilar skull fracture
CSF rhinorrhea or otorrhea: Clear fluid from nose or ear — skull fracture with dural tear

Neck

Meningismus: Nuchal rigidity, Kernig sign, Brudzinski sign — meningitis, subarachnoid hemorrhage (evaluate carefully; protect cervical spine if trauma suspected)
Thyroid: Goiter, thyroidectomy scar — hypocalcemia from hypoparathyroidism, thyroid storm
Lymphadenopathy: May suggest infection, malignancy
Carotid bruits: Cerebrovascular disease, stroke risk
Jugular venous distension: Right heart failure, superior vena cava syndrome (mass)

Oral Examination

Examine the Tongue Carefully

The location of tongue injury is diagnostically important:

Lateral tongue laceration: Highly specific for generalized tonic-clonic seizure (tongue caught between molars during tonic phase)
Tip of tongue bite: Nonspecific — may occur in syncope, psychogenic events, or seizures
Buccal mucosa lacerations: Also support seizure diagnosis

Also examine for: gingival hyperplasia (chronic phenytoin use in known epilepsy), poor dentition, and oral candidiasis (immunocompromised state).

Neurological Examination

A thorough neurological examination is essential to identify focal deficits suggesting a structural lesion and to monitor recovery from the postictal state.

Mental Status

Level of consciousness: Glasgow Coma Scale if decreased; assess orientation to person, place, time, and situation
Attention: Digit span, serial 7s, spelling “WORLD” backward — impaired attention common postictally
Language: Spontaneous speech, naming, repetition, comprehension — dysphasia suggests dominant hemisphere involvement
Memory: Short-term recall — impaired postictally; persistent deficit suggests structural lesion or ongoing nonconvulsive seizures

Cranial Nerves

Cranial Nerve(s)	What to Assess	Abnormality Suggests
II (Optic)	Visual acuity, visual fields, pupillary response, fundoscopy	Papilledema: increased intracranial pressure. Visual field cut: occipital or parietal lesion. Pupil abnormalities: herniation, drug effect
III, IV, VI (Oculomotor, Trochlear, Abducens)	Eye movements, conjugate gaze, nystagmus	Gaze deviation: toward lesion (hemispheric stroke) or away from lesion (seizure focus). Sixth nerve palsy: increased intracranial pressure (false localizing sign)
VII (Facial)	Facial symmetry at rest and with movement	Unilateral weakness: stroke, mass lesion. Lower motor neuron pattern (forehead involved): peripheral lesion
IX, X (Glossopharyngeal, Vagus)	Palate elevation, gag reflex, voice quality	Asymmetry: brainstem lesion. Absent gag: aspiration risk
XII (Hypoglossal)	Tongue protrusion, tongue atrophy, fasciculations	Deviation toward weak side: contralateral hemisphere lesion

Motor Examination

Tone: Increased (spasticity from prior stroke or ongoing seizure activity) or decreased (postictal, medication effect)
Strength: Test all major muscle groups; look for hemiparesis or monoparesis
Todd’s paralysis: Focal weakness following a seizure, typically resolving within 24-48 hours; suggests focal seizure origin and lateralizes to the side of the seizure focus
Pronator drift: Sensitive test for subtle hemiparesis — arms extended, palms up, eyes closed
Asterixis: “Flapping tremor” — metabolic encephalopathy (hepatic, uremic)

Reflexes

Deep tendon reflexes: Asymmetry suggests upper motor neuron lesion; hyperreflexia on one side supports focal pathology
Plantar response: Extensor (Babinski sign) indicates upper motor neuron dysfunction; may be present postictally but should resolve
Clonus: Sustained rhythmic contractions with sustained stretch — upper motor neuron lesion

Sensory and Coordination

Sensory: Test light touch, pinprick, vibration, proprioception — hemisensory loss suggests thalamic or cortical lesion
Coordination: Finger-nose-finger, heel-knee-shin, rapid alternating movements — cerebellar dysfunction (phenytoin toxicity, posterior fossa lesion)
Gait: If patient can safely ambulate — assess for hemiparesis, ataxia, apraxia

Cardiovascular Examination

Important to identify cardiac causes of syncope that may mimic seizure (convulsive syncope):

Heart sounds: Murmurs (aortic stenosis — syncope with exertion), irregular rhythm
Carotid pulses: Asymmetry, bruits — cerebrovascular disease
Peripheral pulses: Quality, symmetry
Edema: Peripheral edema — heart failure, nephrotic syndrome (uremic encephalopathy)
Orthostatic vital signs: If syncope is in the differential — drop in systolic blood pressure greater than 20 mmHg or diastolic greater than 10 mmHg upon standing

Skin Examination

Finding	Description	Associated Condition
Petechial or purpuric rash	Non-blanching lesions, especially with fever	Meningococcemia — medical emergency
Ash-leaf spots	Hypopigmented macules (best seen with Wood’s lamp)	Tuberous sclerosis — associated with epilepsy
Café-au-lait spots	Flat, hyperpigmented macules	Neurofibromatosis type 1 — brain tumors, seizures
Facial angiofibromas	Red papules on face in butterfly distribution	Tuberous sclerosis
Port-wine stain (facial)	Capillary malformation in trigeminal distribution	Sturge-Weber syndrome — cortical venous malformation, seizures
Track marks	Injection sites on arms, between toes	Intravenous drug use — consider intoxication, infection, endocarditis
Jaundice	Yellow discoloration of skin and sclera	Hepatic encephalopathy — asterixis, altered mental status
Spider angiomata, palmar erythema	Signs of chronic liver disease	Hepatic encephalopathy, alcohol-related complications

Expected Findings by Etiology

Condition	General/Vital Signs	Neurological	Other Key Findings
Meningitis/Encephalitis	Fever, tachycardia	Nuchal rigidity, altered mental status, photophobia	Petechial rash (meningococcus), herpetic vesicles (HSV)
Acute stroke	Hypertension, atrial fibrillation	Focal deficits (hemiparesis, aphasia, visual field cut), gaze deviation	Carotid bruit, cardiac murmur
Brain tumor	Often normal vitals	Papilledema, focal deficits, personality changes	Weight loss, lymphadenopathy if metastatic
Alcohol withdrawal	Tachycardia, hypertension, fever, diaphoresis	Tremor, agitation, hallucinations (in severe cases)	Signs of chronic liver disease, poor nutrition
Hypoglycemia	Tachycardia, diaphoresis	Confusion, focal deficits possible, rapid improvement with glucose	Insulin injection sites, diabetic identification
Uremia	Hypertension, Kussmaul breathing	Asterixis, myoclonus, encephalopathy	Pallor, uremic frost (severe), edema
Eclampsia	Severe hypertension, edema	Hyperreflexia, clonus, altered mental status	Pregnant or recently postpartum, proteinuria
Drug intoxication	Variable — tachycardia, hyperthermia with stimulants	Dilated pupils (stimulants), miosis (opioids), agitation or obtundation	Track marks, pill bottles, drug paraphernalia
Idiopathic generalized epilepsy	Normal	Normal (except during postictal period)	No abnormalities; diagnosis based on history and EEG

Important Teaching Point

Normal examination is common in first seizure! Many patients with a first unprovoked seizure — especially those with idiopathic generalized epilepsy, juvenile myoclonic epilepsy, or temporal lobe epilepsy — will have completely normal physical and neurological examinations once the postictal period has resolved. A normal examination does not exclude epilepsy or the need for further workup. The examination primarily helps identify acute symptomatic causes (infection, metabolic derangement, stroke) and neurocutaneous syndromes, and monitors for persistent focal deficits that would suggest a structural lesion requiring urgent imaging.

The Importance of Serial Examination

Re-examine as the postictal state resolves. Many findings in the immediate postictal period (confusion, lethargy, transient focal weakness) will improve over minutes to hours. Serial examinations help to:

Document resolution of postictal confusion (typical: 30-60 minutes; prolonged suggests ongoing seizures or structural pathology)
Distinguish Todd’s paralysis (should improve within 24-48 hours) from stroke (deficits persist)
Identify nonconvulsive status epilepticus if patient fails to improve as expected
Monitor for seizure recurrence

5. Differential Diagnosis

Systematic approach organized by probability and clinical features

When evaluating a patient with a new convulsion or suspected seizure, the differential diagnosis must address two fundamental questions: (1) Was this truly a seizure, or a seizure mimic? and (2) If it was a seizure, what caused it? The approach differs for provoked (acute symptomatic) seizures versus unprovoked seizures, as the underlying causes and management differ substantially.

Step-by-Step Approach to the New Seizure:

Step 1: Confirm this was a seizure — Rule out syncope, psychogenic nonepileptic seizures, and other mimics
Step 2: Identify provoked causes — Check glucose, electrolytes, toxicology; assess for acute brain injury, infection, withdrawal
Step 3: If unprovoked — Classify seizure type (focal versus generalized) and investigate for structural cause or epilepsy syndrome
Step 4: Risk stratify — Determine recurrence risk and need for antiseizure medication

Seizure Mimics — “Was This Really a Seizure?”

Up to 20-30% of patients referred for presumed seizures have an alternative diagnosis. Always consider mimics before attributing an episode to seizure.

Condition	Key Distinguishing Features	Helpful Investigations
Syncope (including convulsive syncope)	Prodrome (lightheadedness, warmth, tunnel vision); brief loss of consciousness (less than 30 seconds); rapid recovery; may have brief myoclonic jerks; triggered by standing, heat, pain, micturition	ECG, orthostatic vital signs, echocardiogram, tilt table testing if recurrent
Psychogenic nonepileptic seizures (PNES)	Eyes often closed; asynchronous movements; side-to-side head movement; pelvic thrusting; prolonged duration; waxing and waning; preserved awareness during apparent “convulsion”; rapid return to baseline; often in presence of others; psychiatric comorbidity	Video-EEG monitoring (gold standard); normal ictal EEG during event; prolactin not elevated
Transient ischemic attack	Negative symptoms (weakness, numbness, visual loss) rather than positive symptoms; no loss of consciousness; duration minutes to hours; vascular risk factors	MRI brain with diffusion-weighted imaging, CT/MR angiography, carotid ultrasound, ECG
Transient global amnesia	Sudden onset anterograde amnesia; repetitive questioning; no loss of consciousness; resolves within 24 hours; no focal deficits	MRI (may show hippocampal diffusion restriction); clinical diagnosis
Movement disorders (dystonia, tics, myoclonus)	No alteration of consciousness; stereotyped movements; may be suppressible; no postictal state	Clinical observation; video documentation; neurology referral
Migraine with aura	Visual, sensory, or motor symptoms spreading over minutes (not seconds); headache follows; personal or family history of migraine	Clinical diagnosis; MRI brain if atypical features
Panic attack	Intense fear; palpitations; hyperventilation; paresthesias; sense of impending doom; no loss of consciousness; often situational trigger	Clinical diagnosis; rule out cardiac and metabolic causes
Hypoglycemia (without seizure)	Diaphoresis, tremor, confusion, behavioral changes; relieved with glucose; diabetic patient	Point-of-care glucose during episode
Sleep disorders (narcolepsy, parasomnias)	Cataplexy triggered by emotion; complex behaviors from sleep; no postictal confusion; occurs from sleep	Polysomnography, multiple sleep latency test

Provoked (Acute Symptomatic) Seizures

Provoked seizures occur in close temporal relationship to an acute systemic or central nervous system insult. Identifying and treating the underlying cause is the priority; long-term antiseizure medication is usually not required.

Probability	Cause	Key Clinical Features	Immediate Action
COMMON	Alcohol withdrawal	Seizure 6-48 hours after last drink; history of heavy alcohol use; tremor, diaphoresis, tachycardia, hypertension	Benzodiazepines; CIWA protocol; thiamine; monitor for delirium tremens
COMMON	Hypoglycemia	Diabetic patient; insulin or sulfonylurea use; missed meal; glucose less than 50-60 mg/dL	IV dextrose or oral glucose; identify cause of hypoglycemia
COMMON	Drug intoxication	Stimulants (cocaine, amphetamines), tramadol, bupropion, isoniazid, theophylline; toxidrome signs	Supportive care; specific antidotes if available (pyridoxine for isoniazid)
COMMON	Medication non-adherence (known epilepsy)	Subtherapeutic antiseizure medication levels; patient admits missing doses	Reload antiseizure medication; address barriers to adherence
LESS COMMON	Hyponatremia	Sodium typically less than 120 mEq/L; acute (less than 48 hours) or chronic; causes include SIADH, diuretics, polydipsia	Hypertonic saline if seizing; avoid rapid correction (osmotic demyelination risk)
LESS COMMON	Acute stroke (ischemic or hemorrhagic)	Focal neurological deficits; seizure at stroke onset or within 7 days; risk factors for cerebrovascular disease	CT head; stroke protocol; short-term antiseizure medication if recurrent early seizures
LESS COMMON	Traumatic brain injury	Early post-traumatic seizure (within 7 days of injury); scalp laceration, bruising; amnesia for event	CT head; seizure prophylaxis for 7 days in severe TBI
LESS COMMON	Central nervous system infection	Meningitis: fever, headache, neck stiffness, altered mental status. Encephalitis: more prominent confusion, focal signs, behavioral changes	Lumbar puncture (if safe); empiric antibiotics and acyclovir; urgent imaging
LESS COMMON	Benzodiazepine or barbiturate withdrawal	Recent cessation of chronic use; anxiety, tremor, autonomic instability; potentially life-threatening	Reinstate benzodiazepine; supervised taper
UNCOMMON BUT SERIOUS	Eclampsia	Pregnant (especially third trimester) or postpartum; hypertension, edema, proteinuria; visual changes, headache	Magnesium sulfate; antihypertensives; urgent obstetric consultation; delivery if severe
UNCOMMON BUT SERIOUS	Hypocalcemia	Post-thyroidectomy; chronic kidney disease; vitamin D deficiency; tetany, Chvostek sign, prolonged QT	IV calcium gluconate; cardiac monitoring
UNCOMMON BUT SERIOUS	Uremia	Advanced chronic kidney disease; asterixis, myoclonus, encephalopathy; very elevated BUN/creatinine	Urgent dialysis consideration
UNCOMMON BUT SERIOUS	Posterior reversible encephalopathy syndrome (PRES)	Severe hypertension; immunosuppressive drugs; headache, visual changes, altered mental status; MRI shows posterior white matter edema	Blood pressure control; remove offending agent; supportive care

Unprovoked Seizures — Epilepsy and Structural Causes

If no acute provocation is identified, the seizure is classified as unprovoked. This may represent the first manifestation of epilepsy (genetic or structural) or a remote symptomatic seizure (due to prior brain injury).

Probability	Condition	Typical Presentation	Key Diagnostic Features
COMMON (approximately 30-40%)	Unknown cause (cryptogenic)	Normal examination; no identifiable structural lesion or genetic cause; often diagnosed as epilepsy if recurrent	Normal MRI; may have epileptiform abnormalities on EEG
COMMON (approximately 20-30%)	Idiopathic generalized epilepsy	Adolescent or young adult; normal neurological examination; may have myoclonic jerks upon awakening; family history	Generalized spike-wave on EEG; normal MRI; genetic predisposition
LESS COMMON (approximately 10-20%)	Remote symptomatic (prior stroke, traumatic brain injury, encephalitis)	History of prior brain injury (months to years ago); focal seizure type; may have residual deficits	MRI shows encephalomalacia, gliosis, or atrophy corresponding to prior injury
LESS COMMON (approximately 10-15%)	Mesial temporal sclerosis	History of febrile seizures in childhood; focal seizures with impaired awareness; aura (rising epigastric sensation, déjà vu); automatisms	MRI shows hippocampal atrophy and signal change; temporal spikes on EEG
LESS COMMON	Brain tumor (primary or metastatic)	Progressive headaches; focal deficits; personality change; known primary cancer; age-dependent (glioma in younger, metastases in older)	MRI with contrast; low-grade tumors often more epileptogenic than high-grade
LESS COMMON	Vascular malformation (arteriovenous malformation, cavernoma)	Often young adult; may present with seizure, hemorrhage, or incidentally discovered; seizures may be focal	MRI (cavernoma: “popcorn” lesion; AVM: flow voids); may require angiography
UNCOMMON	Cortical dysplasia	Childhood or young adult onset; often drug-resistant focal epilepsy; may be subtle on imaging	High-resolution MRI may show focal cortical thickening, blurring of gray-white junction
UNCOMMON	Autoimmune encephalitis	Subacute onset of seizures, psychiatric symptoms, memory problems; may have preceding viral illness or tumor (paraneoplastic)	CSF pleocytosis; autoimmune antibody panel (anti-NMDA receptor, anti-LGI1, anti-CASPR2, etc.); MRI may show mesial temporal signal change
UNCOMMON	Neurodegenerative disease	Older adult; cognitive decline; myoclonus; Alzheimer disease and other dementias increase seizure risk	MRI shows atrophy; clinical syndrome of dementia; EEG may show slowing

Anatomical Approach to Seizure Etiology

Cortical Lesions

Brain tumor (glioma, meningioma, metastasis)

Cortical dysplasia

Stroke (ischemic or hemorrhagic)

Traumatic brain injury / contusion

Encephalitis (especially herpes simplex)

Tuberous sclerosis (cortical tubers)

Mesial Temporal Structures

Mesial temporal sclerosis

Herpes simplex encephalitis

Autoimmune limbic encephalitis

Low-grade temporal lobe tumors

Hippocampal malformations

Cavernous malformations

Diffuse / Generalized

Idiopathic generalized epilepsy (genetic)

Metabolic encephalopathy

Drug intoxication / withdrawal

Anoxic brain injury

Neurodegenerative diseases

Mitochondrial disorders

Vascular / Inflammatory

Arteriovenous malformation

Cerebral venous thrombosis

Vasculitis (primary CNS or systemic)

Posterior reversible encephalopathy syndrome

Subarachnoid hemorrhage

Cerebral amyloid angiopathy

Drug-Induced Seizures

Drug or Drug Class	Mechanism	Characteristics	Management Notes
Bupropion	Dose-dependent lowering of seizure threshold; inhibits reuptake of dopamine and norepinephrine	Risk increases sharply above 450 mg/day; immediate-release formulation higher risk than sustained-release	Contraindicated in patients with seizure history; discontinue if seizure occurs
Tramadol	Lowers seizure threshold; inhibits serotonin and norepinephrine reuptake; weak opioid agonist	Risk even at therapeutic doses; increased risk with SSRIs (serotonin syndrome overlap)	Avoid in epilepsy; caution with serotonergic drugs
Tricyclic antidepressants	Sodium channel blockade (at high levels); anticholinergic effects	Primarily in overdose; QRS widening on ECG; anticholinergic toxidrome	Sodium bicarbonate for cardiac toxicity; benzodiazepines for seizures
Antipsychotics (especially clozapine)	Lowers seizure threshold via multiple mechanisms including D2 blockade and effects on GABA	Clozapine: dose-dependent, approximately 3-5% risk; rapid dose escalation increases risk	Consider prophylactic antiseizure medication with clozapine at higher doses
Fluoroquinolones	GABA-A receptor antagonism	Risk especially in elderly, renal impairment, concurrent NSAIDs or theophylline	Use alternatives when possible in high-risk patients
Carbapenems (imipenem > meropenem)	GABA-A receptor antagonism; imipenem has higher epileptogenic potential	Risk in renal impairment, CNS pathology, concurrent valproate (decreases valproate levels)	Meropenem preferred in patients with seizure risk; dose-adjust for renal function
Isoniazid	Depletes pyridoxine (vitamin B6), required for GABA synthesis	Seizures refractory to benzodiazepines; metabolic acidosis; in overdose or with chronic use without B6 supplementation	Pyridoxine is specific antidote; give gram-for-gram with isoniazid ingested (or 5 grams empirically)
Cocaine and amphetamines	Increased catecholamines; direct neurotoxicity; hyperthermia; hypertensive crisis	May cause seizures during intoxication; also risk of stroke/hemorrhage	Benzodiazepines first-line; avoid beta-blockers (unopposed alpha stimulation); cooling if hyperthermic
Synthetic cannabinoids	Variable and unpredictable effects; may have proconvulsant compounds	Severe presentations with agitation, psychosis, seizures; unknown specific compound often	Supportive care; benzodiazepines; may be difficult to detect on standard drug screens
Theophylline	Adenosine receptor antagonism; phosphodiesterase inhibition; increases catecholamines	Seizures often refractory; may occur at therapeutic levels in elderly; nausea, vomiting, arrhythmias	Check theophylline level; charcoal hemoperfusion or hemodialysis in severe toxicity
Lithium	Multiple mechanisms; neurotoxicity in overdose or chronic toxicity	Coarse tremor, ataxia, confusion, myoclonus; ECG changes; diabetes insipidus	Hemodialysis for severe toxicity; supportive care

Quick Reference: “If You See This, Think This”

Clinical Clue	Think This First	Next Step
Seizure 6-48 hours after last drink + tremor + diaphoresis	Alcohol withdrawal seizure	Benzodiazepines, CIWA protocol, thiamine, monitor for delirium tremens
Diabetic patient + confusion + diaphoresis	Hypoglycemia	Check glucose immediately; IV dextrose if confirmed
Pregnant woman + hypertension + seizure	Eclampsia	Magnesium sulfate, blood pressure control, urgent obstetric consultation
Fever + headache + neck stiffness + seizure	Meningitis/Encephalitis	Empiric antibiotics and acyclovir; lumbar puncture if safe; imaging
Adolescent + seizure upon awakening + myoclonic jerks	Juvenile myoclonic epilepsy	EEG (generalized polyspike-wave); lifelong treatment usually required
Aura (déjà vu, rising epigastric sensation) + automatisms + confusion	Temporal lobe epilepsy	MRI (look for mesial temporal sclerosis); EEG with temporal electrodes
Older adult + focal seizure + progressive headaches + weight loss	Brain tumor (primary or metastatic)	MRI brain with contrast; staging workup if metastatic disease suspected
Post-thyroidectomy + tetany + perioral numbness + seizure	Hypocalcemia (hypoparathyroidism)	IV calcium gluconate; check calcium, PTH, magnesium; ECG for QT prolongation
Eyes tightly closed during event + pelvic thrusting + prolonged duration	Psychogenic nonepileptic seizure	Video-EEG monitoring; avoid escalating antiseizure medications; psychiatric referral
Subacute onset + psychiatric symptoms + memory problems + seizures	Autoimmune encephalitis	MRI, CSF analysis, autoimmune antibody panel; empiric immunotherapy consideration
Severe hypertension + headache + visual changes + posterior white matter changes on MRI	Posterior reversible encephalopathy syndrome (PRES)	Blood pressure control; remove offending agent if applicable
Focal seizures + ash-leaf spots + facial angiofibromas	Tuberous sclerosis	MRI (cortical tubers, subependymal nodules); genetic testing; monitor for complications

6. Diagnostic Investigations

A stepwise, cost-effective approach guided by clinical suspicion

The investigation of a new seizure aims to: (1) identify reversible or treatable causes, (2) assess for structural brain abnormalities, (3) confirm the diagnosis and classify the epilepsy syndrome if applicable, and (4) risk stratify for recurrence. A targeted, clinically guided approach avoids unnecessary testing while ensuring serious causes are not missed.

Immediate Investigations — All Patients with New Seizure

Investigation	Purpose	What to Look For	Practical Points
Point-of-care glucose	Rule out hypoglycemia as cause of seizure	Less than 70 mg/dL suggests hypoglycemia as cause; less than 50 mg/dL highly likely	Check immediately — do not wait for laboratory glucose
Complete metabolic panel	Detect metabolic causes	Sodium less than 125 mEq/L (hyponatremia); glucose; calcium; magnesium; renal function (uremia); liver function	Hyponatremia: assess acuity before correction; Hypocalcemia: check ionized calcium, PTH, magnesium
Complete blood count	Screen for infection, anemia	Leukocytosis (infection); anemia; thrombocytopenia (liver disease, DIC)	Mild leukocytosis may be postictal stress response; interpret in clinical context
Electrocardiogram (ECG)	Identify cardiac cause of syncope mistaken for seizure; detect drug effects	Arrhythmias (especially long QT, Brugada, heart block); prolonged QTc (hypocalcemia, drugs); QRS widening (tricyclic overdose)	Especially important if event had syncopal features or patient has cardiac history
Urine drug screen	Detect intoxication or withdrawal	Cocaine, amphetamines, benzodiazepines, opioids, cannabis, synthetic cannabinoids (may not detect all)	Positive result does not prove causation; negative result does not exclude synthetic drugs
Blood alcohol level	Assess intoxication or withdrawal	Level may be low or zero in withdrawal seizures; high level may contribute but consider other causes	Withdrawal seizures typically occur as alcohol level falls, often when approaching zero
Antiseizure medication levels (if applicable)	Assess adherence in known epilepsy	Subtherapeutic level suggests non-adherence; elevated level suggests toxicity or drug interaction	Draw level before administering loading dose if possible

Neuroimaging

When to Image Emergently

Obtain urgent CT head (non-contrast) in the following situations:

Persistent altered mental status beyond expected postictal period
New focal neurological deficit
Recent head trauma
Patient on anticoagulation
Known malignancy (concern for metastases or hemorrhage)
Immunocompromised patient (opportunistic infection, lymphoma)
Fever with seizure (concern for CNS infection — LP may be needed after CT)
Signs of increased intracranial pressure (papilledema, herniation signs)
First seizure in patient over 40 years

Modality	Indications	What It Detects	Limitations
CT head (non-contrast)	Emergency setting; rule out hemorrhage, large mass, herniation; trauma evaluation	Acute hemorrhage; large tumors; hydrocephalus; major stroke; skull fractures	Limited sensitivity for small lesions, early ischemia, mesial temporal pathology, low-grade tumors
MRI brain (with and without contrast)	All patients with first unprovoked seizure (unless contraindicated); preferred for epilepsy workup	Mesial temporal sclerosis; cortical dysplasia; small tumors; cavernomas; encephalitis; stroke; vascular malformations	May not be immediately available; contraindicated with some implants; requires patient cooperation (sedation may be needed)
Epilepsy-protocol MRI	Recurrent seizures with normal standard MRI; presurgical evaluation; suspected subtle structural cause	Subtle cortical dysplasia; small hippocampal abnormalities; fine structural detail	Requires specialized acquisition and interpretation; not available at all centers
CT or MR angiography	Suspected vascular cause (arteriovenous malformation, aneurysm, venous thrombosis)	Arteriovenous malformations; aneurysms; vessel occlusion; cerebral venous thrombosis	CT requires contrast; MR venography specifically for venous sinus thrombosis

MRI Is Superior to CT for Epilepsy Evaluation

While CT is useful in the emergency setting to exclude hemorrhage and large masses, MRI is the imaging modality of choice for evaluating seizures. MRI detects many important causes of epilepsy that CT will miss, including mesial temporal sclerosis, focal cortical dysplasia, small tumors, cavernous malformations, and encephalitis. All patients with a first unprovoked seizure should eventually have an MRI, even if the initial CT was normal.

Electroencephalography (EEG)

EEG Type	Timing and Setting	What It Detects	Practical Considerations
Routine EEG (20-40 minutes)	Outpatient; ideally within 24-48 hours of seizure for maximum yield	Interictal epileptiform discharges (spikes, sharp waves); focal or generalized slowing; classification of epilepsy syndrome	Sensitivity approximately 50% after first seizure; increases with sleep deprivation and repeat studies; normal EEG does not exclude epilepsy
Sleep-deprived EEG	If routine EEG is normal or nondiagnostic; patient sleeps less than 4 hours before test	Increases detection of epileptiform abnormalities by capturing natural sleep and activating discharges	Especially useful for generalized epilepsies and temporal lobe epilepsy
Prolonged ambulatory EEG (24-72 hours)	When routine EEG is nondiagnostic; need to capture infrequent events	Interictal and possibly ictal activity; correlates symptoms with EEG changes	Patient wears portable EEG at home; limited technical quality compared to inpatient monitoring
Continuous EEG (cEEG) monitoring	ICU setting; unexplained altered mental status; suspected nonconvulsive status epilepticus; after convulsive status epilepticus	Nonconvulsive seizures; nonconvulsive status epilepticus; periodic patterns (e.g., lateralized periodic discharges)	Requires specialized equipment and interpretation; essential in critically ill patients who are not waking up as expected
Video-EEG monitoring	Inpatient epilepsy monitoring unit; presurgical evaluation; diagnosis of suspected psychogenic nonepileptic seizures	Captures seizures on video synchronized with EEG; definitively distinguishes epileptic seizures from PNES	Gold standard for characterizing seizures; may require antiseizure medication reduction to capture events

Interpreting EEG Results:

Epileptiform discharges present: Strongly supports diagnosis of epilepsy; helps classify syndrome and guide treatment; increases recurrence risk after first seizure
Focal slowing only: Suggests underlying structural abnormality in that region; obtain MRI if not already done
Generalized slowing: Nonspecific; may indicate metabolic or toxic encephalopathy, medication effect, or postictal state
Normal EEG: Does NOT rule out epilepsy; approximately 50% of patients with epilepsy have normal interictal routine EEG

Lumbar Puncture

When to Perform Lumbar Puncture

Fever with seizure: Concern for meningitis or encephalitis
Immunocompromised patient: Opportunistic CNS infections
Persistent altered mental status: After imaging rules out mass effect
Suspected autoimmune encephalitis: CSF pleocytosis, autoimmune antibody testing
Suspected subarachnoid hemorrhage with negative CT: Xanthochromia in CSF
HIV-positive patient: Cryptococcal meningitis, toxoplasmosis, lymphoma

CSF Analysis

Opening pressure: Elevated in meningitis, idiopathic intracranial hypertension, venous sinus thrombosis
Cell count and differential: Pleocytosis suggests infection or inflammation
Protein: Elevated in infection, inflammation, tumor
Glucose: Low in bacterial meningitis, TB, fungal
Gram stain and culture: Bacterial meningitis
HSV PCR: Herpes simplex encephalitis
Autoimmune antibody panel: Anti-NMDA receptor, anti-LGI1, anti-CASPR2, anti-GABA-B, and others
Cytology: Leptomeningeal carcinomatosis

Always Image Before Lumbar Puncture If:

Focal neurological deficit
Papilledema or signs of increased intracranial pressure
Altered level of consciousness (GCS less than 13)
Immunocompromised state
History of CNS disease (mass, stroke, infection)
New-onset seizure (within 1 week)

However, do not delay empiric antibiotics and acyclovir while waiting for imaging if meningitis or encephalitis is suspected.

Targeted Investigations by Suspected Etiology

If Suspecting Autoimmune Encephalitis

First-Line Tests

MRI brain: May show T2/FLAIR hyperintensity in mesial temporal lobes (but may be normal)
EEG: May show temporal slowing, extreme delta brush (anti-NMDA receptor), or epileptiform activity
CSF analysis: Lymphocytic pleocytosis in approximately 80%; elevated protein; may have oligoclonal bands

Second-Line Tests

Serum and CSF autoimmune antibody panel: Anti-NMDA receptor, anti-LGI1, anti-CASPR2, anti-GABA-B, anti-AMPA, anti-GAD65
Paraneoplastic workup: CT chest/abdomen/pelvis; testicular ultrasound (teratoma in anti-NMDA receptor encephalitis); PET scan
Pelvic ultrasound or MRI: Ovarian teratoma in young women with anti-NMDA receptor encephalitis

If Suspecting Cerebral Venous Thrombosis

First-Line Tests

MRI brain with MR venography: Shows thrombus in venous sinuses; may show venous infarcts (often hemorrhagic, in non-arterial distribution)
CT venography: Alternative if MRI not available; shows filling defects in sinuses

Second-Line Tests

D-dimer: May be elevated but not specific; normal D-dimer does not rule out CVT
Thrombophilia workup: Factor V Leiden, prothrombin gene mutation, antiphospholipid antibodies, protein C and S, antithrombin III (test after acute period)
Pregnancy test: Pregnancy and postpartum are risk factors

If Suspecting Herpes Simplex Encephalitis

First-Line Tests

MRI brain: T2/FLAIR hyperintensity in mesial temporal lobes, insular cortex, orbitofrontal regions (often asymmetric)
CSF HSV PCR: Sensitivity greater than 95% after first 24-48 hours of symptoms; may be negative very early
CSF analysis: Lymphocytic pleocytosis; elevated protein; RBCs may be present (hemorrhagic necrosis)

Second-Line Tests

EEG: Periodic lateralized epileptiform discharges (PLEDs) over temporal regions; focal temporal slowing
Repeat CSF HSV PCR: If initial PCR negative but clinical suspicion high; repeat in 3-7 days

Note: Do not wait for test results to start empiric acyclovir. Treatment should begin immediately if HSE is suspected.

Serum Prolactin: A Specialized Test

When Prolactin May Help

Serum prolactin can help distinguish epileptic seizures from psychogenic nonepileptic seizures (PNES) in selected cases:

Timing: Draw 10-20 minutes after suspected event (peak at 10-20 minutes, returns to baseline by 6 hours)
Interpretation: Elevation greater than 2 times baseline (or greater than 2-3 times upper limit of normal) supports generalized tonic-clonic or focal seizure with impaired awareness
Limitations: Not elevated after all seizure types (especially frontal lobe seizures); may be elevated by syncope; requires baseline for comparison; not useful for status epilepticus
Use: Primarily in epilepsy monitoring units to help interpret captured events; not routinely used in emergency department

Investigation Summary by Clinical Setting

Setting	Essential Investigations	Consider Adding
Emergency Department — First Seizure	Glucose, BMP, CBC, urine drug screen, blood alcohol, ECG, CT head	LP (if fever/immunocompromised), toxicology levels, liver function tests, antiseizure medication levels (if known epilepsy)
Outpatient Follow-up — Post-First Seizure	MRI brain with and without contrast, routine EEG	Sleep-deprived EEG if routine EEG normal, extended EEG monitoring if diagnosis uncertain
ICU — Refractory Status Epilepticus	Continuous EEG, comprehensive metabolic panel, MRI when stable, LP (if infection/autoimmune suspected)	Autoimmune encephalitis panel, toxicology screen, paraneoplastic workup, genetic testing in young patients
Epilepsy Clinic — Recurrent Seizures	Epilepsy-protocol MRI (if standard MRI negative), video-EEG monitoring	Genetic testing, neuropsychological evaluation, PET or SPECT (presurgical evaluation), functional MRI

7. Pattern Recognition and Clinical Decision-Making

Practical algorithms and decision pathways

Clinical decision-making in seizure management requires rapid triage to identify emergencies, systematic evaluation to determine etiology, and evidence-based decisions about initiating antiseizure therapy. This section provides practical algorithms for common clinical scenarios encountered in the family medicine and emergency setting.

Step 1: Is This Urgent?

Clinical Scenario	Urgency Level	Immediate Action
Active seizure greater than 5 minutes OR repeated seizures without recovery	EMERGENT	Status epilepticus protocol: Airway, IV access, benzodiazepine (lorazepam 4 mg IV or midazolam 10 mg IM), check glucose, prepare second-line agents
Seizure with fever, headache, or neck stiffness	EMERGENT	Suspect CNS infection: Empiric antibiotics and acyclovir immediately, CT head, lumbar puncture when safe
Seizure in pregnancy or postpartum (especially with hypertension)	EMERGENT	Assume eclampsia: Magnesium sulfate 4-6 g IV loading dose, blood pressure control, urgent obstetric consultation
New focal neurological deficit after seizure (not improving)	EMERGENT	Consider stroke or mass lesion: Urgent CT/MRI, neurology consultation, stroke protocol if indicated
Seizure following significant head trauma	EMERGENT	CT head to rule out intracranial hemorrhage, neurosurgical consultation if bleeding present
Patient on anticoagulation with new seizure	URGENT	CT head to rule out intracranial hemorrhage, check INR/coagulation studies, consider reversal if bleeding
First unprovoked seizure, now back to baseline	URGENT	Complete metabolic workup, CT head (in ED), arrange outpatient MRI and EEG, safety counseling, neurology referral
Known epilepsy, breakthrough seizure, back to baseline	URGENT	Check antiseizure medication levels, assess adherence, evaluate for triggers (sleep deprivation, illness, medication changes)
Suspected alcohol withdrawal seizure, otherwise stable	URGENT	Benzodiazepine protocol (CIWA), thiamine, monitor for progression to delirium tremens, consider admission
Suspected psychogenic nonepileptic seizure, patient stable	ROUTINE	Avoid unnecessary antiseizure medication escalation, arrange video-EEG monitoring, psychiatric referral

Step 2: Status Epilepticus Treatment Algorithm

Status Epilepticus: Time-Critical Management

Status epilepticus is defined as continuous seizure activity for ≥5 minutes OR ≥2 seizures without return to baseline. Mortality is 10-20%, and neuronal injury begins after 30 minutes of continuous seizure activity. Early benzodiazepine treatment is critical.

Time	Phase	Action
0-5 minutes	Stabilization	Protect airway (positioning, suction); do NOT insert anything in mouth Administer oxygen Establish IV access (two large-bore IVs if possible) Check point-of-care glucose — give dextrose if hypoglycemic Give thiamine 100 mg IV if alcoholism suspected (before or with glucose) Attach monitors (cardiac, pulse oximetry)
5-20 minutes	First-line therapy	IV access: Lorazepam 4 mg IV (may repeat once in 5-10 minutes) OR Diazepam 10 mg IV No IV access: Midazolam 10 mg IM (preferred) OR Diazepam 20 mg rectal OR Midazolam 10 mg intranasal/buccal Prepare second-line agent while first-line is administered
20-40 minutes	Second-line therapy (if seizures persist)	Fosphenytoin: 20 mg PE/kg IV at 150 mg PE/min (monitor ECG, BP) OR Levetiracetam: 60 mg/kg IV (max 4500 mg) over 15 minutes OR Valproate: 40 mg/kg IV (max 3000 mg) over 10 minutes If one second-line agent fails, may try another before proceeding to third-line
40+ minutes	Refractory status epilepticus	Intubation and ICU admission required Options: Propofol infusion, Midazolam infusion, Pentobarbital infusion Continuous EEG monitoring essential Treat underlying cause aggressively

Step 3: First Unprovoked Seizure — To Treat or Not to Treat?

The Key Question: Should antiseizure medication be started after a first unprovoked seizure?

The decision depends on the estimated risk of recurrence. Overall risk after a single unprovoked seizure is approximately 40-50% within 2 years. Treatment reduces recurrence risk by approximately 50% but does not alter long-term remission rates. The decision should be individualized based on risk factors and patient preferences.

Clinical Scenario	Estimated Recurrence Risk	Recommendation
First seizure + normal EEG + normal MRI + no risk factors	Approximately 25-30% over 2 years	Treatment optional; discuss risks and benefits with patient; many choose to defer treatment and observe
First seizure + epileptiform abnormalities on EEG	Approximately 60-70% over 2 years	Meets ILAE criteria for epilepsy diagnosis; recommend treatment
First seizure + structural lesion on MRI (prior stroke, tumor, etc.)	Approximately 60-70% over 2 years	Meets ILAE criteria for epilepsy diagnosis; recommend treatment
First seizure + Todd’s paralysis or other postictal focal deficit	Higher than baseline	Suggests focal onset; recommend MRI; likely to benefit from treatment
First seizure + family history of epilepsy + EEG abnormalities	Approximately 60% or higher	Consider treatment, especially if patient has high-risk occupation or driving needs
Two or more unprovoked seizures (more than 24 hours apart)	Approximately 70-80%	Epilepsy diagnosis established; antiseizure medication recommended

Factors Favoring Treatment After First Seizure

Abnormal EEG with epileptiform discharges
Structural brain lesion on MRI
Nocturnal seizure (higher recurrence risk)
Patient preference (anxiety about recurrence, driving needs)
High-risk occupation (pilot, commercial driver, working at heights)
Status epilepticus as initial presentation
Prior brain injury (stroke, trauma, encephalitis)

Step 4: Choosing Initial Antiseizure Medication

Seizure Type / Syndrome	First-Line Options	Medications to AVOID
Focal seizures (with or without secondary generalization)	Levetiracetam, Lamotrigine, Carbamazepine, Oxcarbazepine, Lacosamide	Ethosuximide (not effective for focal)
Generalized tonic-clonic seizures (primary generalized)	Levetiracetam, Lamotrigine, Valproate	Carbamazepine, Oxcarbazepine, Phenytoin (may worsen some generalized epilepsies)
Absence seizures	Ethosuximide (first-line if absence only), Valproate, Lamotrigine	Carbamazepine, Phenytoin, Gabapentin, Tiagabine (may worsen absences)
Juvenile myoclonic epilepsy	Valproate, Levetiracetam, Lamotrigine (use cautiously — may worsen myoclonus)	Carbamazepine, Oxcarbazepine, Phenytoin, Gabapentin (worsen myoclonus)
Unknown seizure type (unable to classify)	Levetiracetam, Lamotrigine, Valproate (broad-spectrum options)	Narrow-spectrum medications until classification clarified
Women of childbearing potential	Levetiracetam, Lamotrigine, Oxcarbazepine (lower teratogenic risk)	Valproate (contraindicated — high teratogenic risk, developmental effects)
Elderly patients	Levetiracetam, Lamotrigine, Lacosamide (fewer drug interactions, better tolerability)	Enzyme-inducing drugs if on multiple medications (phenytoin, carbamazepine, phenobarbital)

“What Do I Do If…” Decision Reference

Clinical Situation	Immediate Action	Next Step
Patient seizes in my office?	Protect from injury (move objects away, cushion head); turn on side if possible; do NOT restrain or put anything in mouth; note time	Call emergency services if seizure lasts greater than 5 minutes or patient doesn’t regain consciousness; stay with patient; provide information to EMS
Known epilepsy patient has breakthrough seizure?	Check medication adherence; check antiseizure medication levels; evaluate for triggers (sleep deprivation, illness, new medications, alcohol)	If levels subtherapeutic — reload and reinforce adherence; if therapeutic — consider dose increase or add-on therapy; neurology follow-up
Witnessed event unclear if seizure or syncope?	Detailed history from patient AND witness; review event characteristics (prodrome, duration, postictal state, tongue bite location)	ECG and orthostatic vitals for all; EEG if seizure suspected; echocardiogram and Holter if cardiac syncope suspected; consider tilt table
Suspected psychogenic nonepileptic seizures (PNES)?	Do NOT escalate antiseizure medications; maintain supportive, non-judgmental approach; avoid excessive emergency interventions	Refer for video-EEG monitoring for definitive diagnosis; psychiatric evaluation; explain that PNES is real and treatable (not “faking”)
Patient asks about driving after seizure?	Advise patient not to drive until cleared; explain legal requirements (vary by jurisdiction — typically 3-12 months seizure-free)	Document counseling; know local regulations; provide written information; follow up to determine when driving can resume
Female patient with epilepsy wants to become pregnant?	Review current medications for teratogenic risk; ensure high-dose folic acid (4 mg daily); optimize seizure control before conception	Switch away from valproate if possible; refer to high-risk obstetrics and epilepsy specialist; discuss risks of seizures during pregnancy
Older adult with new seizure and no obvious cause?	Low threshold for imaging (CT now, MRI as outpatient); consider stroke, tumor, metabolic causes, medication effect	MRI with contrast to evaluate for tumor or prior stroke; EEG; review all medications for seizure-lowering threshold
Patient not improving as expected after seizure?	Consider nonconvulsive status epilepticus; obtain urgent EEG (continuous monitoring if available)	If nonconvulsive status confirmed — treat aggressively; if EEG negative — evaluate for other causes of altered mental status

Safety Counseling and Driving Restrictions

Essential Safety Counseling After Seizure

All patients with a new seizure should receive counseling on safety precautions:

Driving: Advise against driving until meeting jurisdictional requirements (typically 3-12 months seizure-free depending on location); document this conversation
Bathing: Showers preferred over baths (drowning risk); avoid locked bathroom doors
Swimming: Never swim alone; always with supervision and informed companion
Heights and machinery: Avoid ladders, scaffolding, operating heavy machinery until seizure-free
Supervision: Consider having someone check on patient regularly, especially if living alone
Medication adherence: Emphasize importance of not missing doses; discuss pill organizers, alarms
Lifestyle factors: Adequate sleep, limit alcohol, avoid known triggers
SUDEP counseling: Discuss risk of Sudden Unexpected Death in Epilepsy; risk reduced with good seizure control and medication adherence

When to Refer to Neurology / Epilepsy Specialist

Urgent Referral

Status epilepticus or repeated seizures
Seizure with focal neurological deficit
Suspected CNS infection or autoimmune encephalitis
Structural lesion on imaging
Pregnancy with seizure
Uncertain diagnosis (seizure vs. mimic)

Routine Referral

First unprovoked seizure (for EEG, MRI interpretation, treatment decisions)
Breakthrough seizures despite treatment
Medication side effects requiring change
Drug-resistant epilepsy (failure of two appropriate medications)
Consideration of medication withdrawal after prolonged seizure freedom
Women with epilepsy planning pregnancy
Presurgical evaluation for refractory epilepsy

8. Clinical Pearls and Pitfalls

Practical wisdom — learn from successes and avoid common mistakes

Must-Know Clinical Pearls

Lateral tongue biting is your friend: A laceration on the side of the tongue is highly specific for generalized tonic-clonic seizure (greater than 95% specificity). Ask specifically and look carefully — this finding can clinch the diagnosis when the history is unclear.

Witnesses overestimate seizure duration: A “5-minute seizure” reported by a frightened family member is often 30-60 seconds. Use the witness’s phone to check for videos or timestamps. True status epilepticus (greater than 5 minutes) is less common than perceived.

The witness history is often more valuable than the patient history: The patient typically has no memory of the ictal period. Always try to contact a witness by phone if not present — their description of the event is crucial for diagnosis and classification.

Check glucose immediately — every time: Hypoglycemia is a rapidly reversible cause of seizures. A bedside glucose takes 10 seconds and can change management entirely. Never skip this step, even if the patient “doesn’t look hypoglycemic.”

Alcohol withdrawal seizures come in clusters: Approximately 40% of patients with one alcohol withdrawal seizure will have another within 6 hours. These patients need observation, not just treatment of the first seizure. The risk of progression to delirium tremens is real.

MRI finds what CT misses: CT is useful emergently to exclude hemorrhage and large masses, but MRI is far superior for identifying causes of epilepsy (mesial temporal sclerosis, cortical dysplasia, small tumors, encephalitis). Always arrange MRI even after a normal CT.

Eyes closed during “seizure” = think PNES: Patients with epileptic seizures almost always have their eyes open (often deviated). Tightly closed eyes, especially with resistance to passive opening, strongly suggests psychogenic nonepileptic seizures.

Sleep deprivation is a potent and underappreciated trigger: Always ask about sleep patterns. In patients with juvenile myoclonic epilepsy or other generalized epilepsies, a single night of poor sleep can precipitate a breakthrough seizure despite good medication adherence.

Juvenile myoclonic epilepsy is often misdiagnosed for years: The morning myoclonic jerks (“clumsy in the morning,” dropping things at breakfast) are frequently dismissed as normal or not reported by patients. Ask specifically: “Do you ever have sudden jerking movements, especially when tired or upon waking?”

Benzodiazepines work best when given early: GABA receptors internalize during prolonged seizures, making benzodiazepines progressively less effective. The sooner benzodiazepines are given, the more likely they are to terminate the seizure. Don’t wait — treat at 5 minutes.

Critical Pitfalls to Avoid

Diagnosing epilepsy after a single provoked seizure: Seizures caused by acute provoking factors (hypoglycemia, alcohol withdrawal, acute stroke, medication toxicity) do not establish a diagnosis of epilepsy and often do not require long-term antiseizure medication. Identify and treat the underlying cause first.

Labeling convulsive syncope as epilepsy: Brief myoclonic jerks during syncope (“convulsive syncope”) are common and do not indicate epilepsy. The key differentiators are prodrome (lightheadedness, warmth, tunnel vision in syncope), duration (syncope is brief), and rapid recovery without prolonged postictal confusion.

Assuming psychogenic nonepileptic seizures and epilepsy are mutually exclusive: Up to 10-20% of patients with PNES also have epileptic seizures. The presence of PNES does not rule out epilepsy, and vice versa. Video-EEG monitoring is essential to characterize all event types.

Using carbamazepine or phenytoin for generalized epilepsy syndromes: Sodium channel blockers (carbamazepine, oxcarbazepine, phenytoin) can worsen absence seizures and myoclonic seizures. In juvenile myoclonic epilepsy, they may paradoxically increase seizure frequency. Use broad-spectrum agents (levetiracetam, valproate, lamotrigine) for generalized epilepsies.

Prescribing valproate to women of childbearing potential without discussion: Valproate has the highest teratogenic risk of common antiseizure medications and is associated with reduced IQ in children exposed in utero. It should be avoided in women who may become pregnant unless no alternative is effective. Always discuss this and document the conversation.

Forgetting to ask about medication adherence before adding second agent: Non-adherence is the most common cause of breakthrough seizures in patients with known epilepsy. Always check medication levels and specifically ask about missed doses before escalating therapy. A patient on no medication doesn’t need a second medication — they need the first one.

Missing nonconvulsive status epilepticus: If a patient is not waking up as expected after a convulsive seizure, or has unexplained altered mental status, consider nonconvulsive status epilepticus. The only way to diagnose this is with EEG. A patient who is “just postictal” for hours may be actively seizing.

Stopping antiseizure medication abruptly: Abrupt discontinuation of antiseizure medications can precipitate seizures or even status epilepticus, including in patients who may not actually have epilepsy. Medications should always be tapered gradually under supervision.

Failing to counsel about driving restrictions: Physicians have a legal and ethical obligation to counsel patients about driving restrictions after seizure. Failure to document this counseling creates medicolegal risk. Know your jurisdiction’s requirements and document the conversation clearly.

Overlooking pregnancy in a seizing woman: Any woman of childbearing age presenting with seizure and hypertension should be assumed to have eclampsia until proven otherwise. Check a pregnancy test; the treatment (magnesium sulfate) is specific and potentially lifesaving.

Key Takeaways

First, confirm it was a seizure: Up to 20-30% of patients referred for seizures have an alternative diagnosis. Detailed history from patient AND witness is essential. Key features favoring seizure include lateral tongue biting, postictal confusion lasting greater than 5 minutes, and loss of consciousness with tonic-clonic movements.
Always check glucose immediately: Hypoglycemia is a rapidly reversible cause of seizures. Point-of-care glucose should be checked in every patient with seizure or altered mental status.
Distinguish provoked from unprovoked seizures: Provoked seizures (due to acute metabolic derangement, intoxication, withdrawal, acute brain injury) often do not require long-term antiseizure medication. Treat the underlying cause.
Status epilepticus is a medical emergency: Defined as seizure activity for ≥5 minutes or repeated seizures without return to baseline. Early benzodiazepine treatment is critical; delayed treatment reduces effectiveness.
MRI is superior to CT for epilepsy evaluation: While CT excludes hemorrhage and large masses emergently, MRI detects many important causes of epilepsy (mesial temporal sclerosis, cortical dysplasia, small tumors) that CT misses.
A normal EEG does not rule out epilepsy: Approximately 50% of patients with epilepsy have a normal routine interictal EEG. If clinical suspicion is high, pursue sleep-deprived EEG or prolonged monitoring.
Treatment after first seizure is individualized: Overall recurrence risk after first unprovoked seizure is approximately 40-50%. Risk is higher with abnormal EEG or structural lesion (approximately 60-70%), meeting criteria for epilepsy diagnosis after a single seizure.
Choose antiseizure medication based on seizure type and patient factors: Broad-spectrum agents (levetiracetam, lamotrigine, valproate) are safe for unknown or generalized seizure types. Avoid valproate in women of childbearing potential. Avoid sodium channel blockers in generalized epilepsies.
Safety counseling is mandatory: All patients must be counseled about driving restrictions, water safety, and activity modifications. Document this conversation. Know your jurisdiction’s driving laws.
Consider nonconvulsive status epilepticus in unexplained altered mental status: If a patient is not improving as expected after a seizure, or has unexplained encephalopathy, obtain EEG to rule out ongoing nonconvulsive seizures.

Quick Reference Algorithm

Systematic Approach to New Seizure:

Stabilize: Airway, breathing, circulation; protect patient from injury; check glucose immediately; give benzodiazepine if seizing greater than 5 minutes
Confirm seizure: Obtain detailed history from patient AND witness; distinguish from syncope, PNES, other mimics using key features (tongue biting, postictal state, eye position, duration)
Identify provoked causes: Complete metabolic panel, urine drug screen, blood alcohol; evaluate for infection, stroke, trauma, medication effects, withdrawal
Image the brain: CT head emergently if red flags present; MRI for all patients with first unprovoked seizure (outpatient if stable)
Obtain EEG: Routine EEG within 24-48 hours for maximum yield; sleep-deprived or prolonged EEG if initial study nondiagnostic
Risk stratify and decide on treatment: Assess recurrence risk based on EEG, imaging, and clinical factors; discuss treatment options with patient; consider deferring treatment if low risk
Counsel and educate: Driving restrictions, water safety, activity modifications, medication adherence, trigger avoidance (sleep deprivation, alcohol); provide written materials
Arrange follow-up: Neurology referral for most patients with first seizure; earlier if diagnostic uncertainty, structural lesion, or treatment required