Seizure Classification
Focal (partial) onset: originates in one hemisphere. Focal aware (simple partial): consciousness preserved; may have motor (Jacksonian march — sequential spread), sensory, autonomic, or psychic symptoms. Focal impaired awareness (complex partial): consciousness impaired; automatisms (repetitive semi-purposeful movements — lip-smacking, hand-wringing); most commonly from temporal lobe. Focal to bilateral tonic-clonic: spreads to involve both hemispheres. Generalized onset: both hemispheres involved from onset. Absence: brief (5–10s) staring spells, abrupt onset/offset, no post-ictal confusion; 3Hz spike-wave on EEG; ethosuximide first-line; commonly mistaken for daydreaming. Tonic-clonic (grand mal): LOC + tonic phase (rigidity) → clonic phase (rhythmic jerking) → post-ictal confusion (minutes to hours). Myoclonic: brief shock-like muscle jerks, usually morning; common in juvenile myoclonic epilepsy (JME). Atonic (drop attacks): sudden loss of muscle tone → falls; associated with Lennox-Gastaut syndrome.
First Seizure Evaluation
Not all first seizures require treatment. Evaluation goal: identify a symptomatic/provoked cause (which must be treated separately) vs unprovoked seizure (epilepsy diagnosis). Provoked seizures: hypoglycemia, hyponatremia, hypernatremia, hypocalcemia, hypomagnesemia, uremia, fever (febrile seizures in children), alcohol withdrawal, drug toxicity, head trauma, CNS infection. All first seizures: glucose, BMP (Na, Ca, Mg), tox screen, head CT (to exclude hemorrhage, mass). MRI brain with and without contrast: best for structural lesion workup — perform if CT negative and no clear metabolic cause. EEG: essential for classification and epilepsy diagnosis (but a normal EEG does not exclude epilepsy). LP: if fever + nuchal rigidity suggest meningitis or encephalitis. Who to treat after first unprovoked seizure: if risk of recurrence >60% (structural brain lesion, prior stroke, developmental delay, epileptiform EEG, nocturnal seizure) — start AED.
Status Epilepticus
Status epilepticus: seizure lasting ≥5 minutes OR ≥2 sequential seizures without return to baseline. Emergency. Neuronal injury begins at 30+ minutes. Treatment sequence (time-based): 0–5 min: IV access, oxygen, labs (glucose, BMP, AED levels, tox screen). 5–20 min (Benzodiazepine phase): lorazepam 0.1 mg/kg IV (or IM midazolam if no IV access, or rectal diazepam). Repeat once if no response. 20–40 min (Second-line AED phase): if benzos fail: fosphenytoin IV (preferred — less cardiotoxic than phenytoin), OR levetiracetam IV, OR valproate IV. 40+ min (Refractory SE): propofol, midazolam, or barbiturate (phenobarbital/pentobarbital) infusion with continuous EEG monitoring; consider intubation for airway protection.
AED Selection by Seizure Type
Focal seizures: levetiracetam (first-line, minimal drug interactions), carbamazepine/oxcarbazepine, lacosamide, lamotrigine. Generalized tonic-clonic: valproate (broadest spectrum; teratogenic — avoid in women of childbearing age), levetiracetam, lamotrigine. Absence: ethosuximide (first-line for pure absence without GTC); valproate (if absence + GTC). Juvenile myoclonic epilepsy: valproate first-line; levetiracetam, lamotrigine. AEDs to avoid: carbamazepine and phenytoin WORSEN absence, myoclonic, and atonic seizures — dangerous if misclassified. Valproate major side effects: weight gain, hepatotoxicity, pancreatitis, tremor, thrombocytopenia, neural tube defects (teratogenic). Phenytoin unique toxicity: gingival hyperplasia, hirsutism, coarse facial features, peripheral neuropathy, cerebellar atrophy (chronic), zero-order kinetics (small dose change → large level change).