Seizure Disorders

BASICS

Seizure: Sudden, transient neurological symptoms due to abnormal neuronal electrical activity (altered consciousness, motor, sensory, or behavioral).
Epilepsy: ≥2 unprovoked seizures >24 hours apart OR 1 unprovoked seizure with a ≥60% risk of recurrence.
Status epilepticus: Seizure >5 minutes or multiple seizures without regaining baseline; neurologic emergency.
Classification: By origin (focal, focal to bilateral, generalized), awareness (aware, impaired, generalized), and features (motor, nonmotor).

Incidence: 200,000 new epilepsy cases/year in US (45,000 children <15 years)
Prevalence: 1.2% of US population (2015 data)

Mechanism: Synchronous, excessive neuronal firing (imbalance: excitatory > inhibitory).
Acute symptomatic causes: Acute brain insult, metabolic disturbance, infection, toxins/drugs, withdrawal
Common acute triggers: Stroke, TBI, subdural/subarachnoid hemorrhage, infection, metabolic/endocrine disorders, drug intoxication
Medication triggers: Opioids, anticancer, antibiotics, hypoglycemics, immunosuppressants, psychotropics, decongestants
Genetics: Family history ×3 risk; numerous genetic syndromes (Angelman, tuberous sclerosis, Sturge-Weber, etc.)
By age:
Neonates: benign neonatal seizures, familial epilepsy, vitamin B6 deficiency
Childhood: febrile seizures, absence
Adolescence: AV malformation
Adults >60: stroke, metabolic, drugs

Genetic syndromes, CNS infections/tumors, drug/alcohol abuse, trauma, metabolic disorders, menstrual hormonal changes

Generalized seizures: Tonic-clonic, absence, atonic, myoclonic
Focal seizures:
Retained awareness (simple partial): Symptoms depend on cortical focus; auras; postictal phase
Impaired awareness (complex partial): Most common adult epilepsy; automatisms, postictal confusion
May spread to generalized tonic-clonic
Nonconvulsive status: Especially in ICU, diagnosed via EEG
PNES: Psychogenic nonepileptic seizures—psychiatric association
Febrile seizures: <6 years, with fever and no other clear cause

EEG: Not always diagnostic—single test sensitivity ~20%, up to 80% with repeated/sleep deprivation
Video EEG: For unclear cases or to distinguish PNES
Labs: Glucose, sodium, calcium, magnesium, BUN, ammonia, toxicology, AED levels, CBC, UA, ECG
Imaging:
CT: Initial evaluation, especially ER
MRI: Temporal lobes, structural lesions (superior)
Lumbar puncture: If infection suspected

AED selection: Based on seizure type, comorbidities, side-effect profile
Monotherapy preferred, titrate dose until control or SE
First-line AEDs:
Levetiracetam: 1000–4000 mg/d (BID)
Carbamazepine: 100–200 mg/d (divided), TR 4–12 mg/L
Lamotrigine: Start 25 mg/d, titrate by 50 mg/wk to 225–375 mg/d (IR), 300–400 mg/d (ER)
Oxcarbazepine: 900–2400 mg/d
Lacosamide: 200–400 mg/d (BID)
Ethosuximide: 20–40 mg/kg/d, TR 40–100 µg/mL (absence)
Status epilepticus:
Lorazepam: 4 mg IV (may repeat in 5–10 min)
Midazolam/Diazepam: 10 mg IV (repeat if needed)
Fosphenytoin: 20 mg phenytoin equiv/kg
Valproic acid: 15–45 mg/kg IV
Levetiracetam: 60 mg/kg IV (max 4.5 g)
Lacosamide: 10 mg/kg IV (max 200 mg)
Second-line/adjuncts: Phenytoin, valproic acid, topiramate, gabapentin, pregabalin, zonisamide, perampanel, clonazepam, clobazam, rufinamide, brivaracetam

Refractory: Consider surgery (lobectomy, resection, laser ablation), vagal nerve stimulator
Psychotherapy, cognitive-behavioral therapy, relaxation, yoga as adjuncts
Ketogenic diet: Useful in children with refractory epilepsy

Monitor: Drug levels, CBC, labs as indicated (vitamin D, BMD), seizure frequency, behavior/suicide risk
Withdraw/taper drugs only after ≥2 years seizure-free; relapse in ~33% within 3 years
Patient education: Avoid triggers, seizure precautions, driving laws (see: https://www.epilepsy.org)
Diet: Ketogenic for refractory pediatric cases