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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- Epilepsy requires recurrent unprovoked seizures or one seizure with high recurrence risk
- First seizure evaluation includes glucose/electrolytes, pregnancy test when relevant, EEG, and MRI when indicated
- Focal seizures originate in one hemisphere; generalized seizures involve bilateral networks from onset
- Ethosuximide is first-line for absence seizures
- Differentiate seizures from syncope, migraine aura, and psychogenic nonepileptic events
Overview
A seizure is a transient event from abnormal excessive neuronal activity. Epilepsy is diagnosed after two unprovoked seizures, one unprovoked seizure with high recurrence risk, or a defined epilepsy syndrome. Classification and treatment depend on focal versus generalized onset.
Epidemiology
Epilepsy has higher incidence in childhood and older adulthood. Causes include genetic epilepsies, cortical malformations, trauma, stroke, tumor, infection, alcohol withdrawal, and metabolic derangements. Provoked seizures do not automatically establish epilepsy.
Clinical Features
Symptoms
Focal aware seizure with retained awareness and motor, sensory, autonomic, or psychic symptoms
Focal impaired awareness seizure with automatisms and postictal confusion
Generalized tonic-clonic seizure with loss of consciousness and postictal period
Absence seizure with brief staring and immediate recovery
Morning myoclonic jerks suggest juvenile myoclonic epilepsy
Signs
Tongue biting, incontinence, and postictal confusion support epileptic seizure
Todd paralysis can mimic stroke after a seizure
Focal deficit after first seizure suggests structural lesion
Fever, meningismus, papilledema, or immunosuppression requires urgent secondary-cause workup
Video EEG is needed for suspected psychogenic nonepileptic seizures
Investigations
First-line
Point-of-care glucose and BMPIdentify hypoglycemia, hyponatremia, hypocalcemia, renal failure
Pregnancy testGuides medication choice and eclampsia evaluation
EEGSupports classification; normal EEG does not exclude epilepsy
MRI brain with epilepsy protocolPreferred for unprovoked adult-onset or focal seizure
Second-line
CT headEmergency imaging for trauma, anticoagulation, cancer, persistent altered state, focal deficit
Toxicology/ethanolWhen intoxication, withdrawal, or overdose suspected
Lumbar punctureIf meningitis, encephalitis, or SAH suspected after safe imaging
Specialist
Video EEG monitoringDiagnostic uncertainty, presurgical workup, or PNES
Epilepsy surgery evaluationDrug-resistant focal epilepsy after two appropriate medications
1
First seizure approach
- ABCs and bedside glucose first
- Treat provoked causes directly
- Start medication after first unprovoked seizure if high recurrence risk
- Counsel driving, swimming, heights, machinery, and adherence
2
Medication selection
- Focal epilepsy: levetiracetam, lamotrigine, carbamazepine, oxcarbazepine, lacosamide
- Generalized seizures: levetiracetam, lamotrigine, valproate, topiramate depending patient factors
- Absence seizures: ethosuximide first-line
- Avoid valproate when pregnancy is possible if safer options work
3
Adverse effects
- Valproate: neural tube defects, hepatotoxicity, weight gain, thrombocytopenia
- Carbamazepine: hyponatremia, cytopenias, SJS/TEN, CYP induction
- Lamotrigine: rash/SJS risk; titrate slowly
- Levetiracetam: irritability and mood symptoms
4
Refractory epilepsy
- Consider surgery for resectable focal epilepsy
- Vagus nerve stimulation or responsive neurostimulation in selected cases
- Ketogenic diet in selected refractory pediatric epilepsy
Complications
- Status epilepticus: Seizure >=5 minutes or recurrent seizures without baseline recovery
- SUDEP: Risk increased with uncontrolled generalized tonic-clonic seizures
- Injury: Falls, burns, drowning, motor vehicle crashes
- Medication toxicity: Teratogenicity, rash, cytopenias, hepatic injury
USMLE Step 2 CK Exam Tips
- 1Active seizure: ABCs and glucose first
- 2Absence seizure = 3-Hz spike-wave; treat with ethosuximide
- 3Temporal lobe epilepsy = deja vu, fear, rising epigastric aura, automatisms
- 4Carbamazepine can worsen absence and myoclonic seizures
- 5Valproate is teratogenic
- 6Todd paralysis mimics stroke
- 7PNES diagnosis is confirmed by video EEG
practicetest your knowledge on epilepsy & seizuresApply what you've learnt with USMLE Step 2 CK-style questions from the iatroX Q-Bank — neurology and beyond.
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