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Seizures: Detail and Management

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1. Definitions

• After 1 unprovoked seizure: ~40-50% risk of a second within 2-8 years
• After 2 unprovoked seizures: ~60-90% risk of a third within 4 years
• Frameworks for Internal Medicine, p. 559

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2. ILAE 2017 Classification of Seizure Types

Focal Onset Seizures (formerly Partial)

Generalized Onset Seizures

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3. Seizure Types in Detail

Absence Seizures

• Onset age 5-15 years; family history in 20-40% of patients
• Abrupt behavioral arrest, no warning, no postictal phase, usually 10-15 seconds (up to 40s)
• Simple absence: altered consciousness only
• Complex absence: altered consciousness + eyelid flutter, minor automatisms, autonomic changes (pallor, tachycardia, urinary incontinence)
• Office diagnosis: hyperventilate for 3-4 minutes often induces an episode
• Bradley and Daroff's Neurology, p. 38

Tonic-Clonic Seizures

• No warning/aura in primary generalized form
• Tonic phase (10-20 s): sustained muscle contraction; apnea, cyanosis, hypertension, incontinence possible
• Clonic phase: rhythmic synchronous muscle jerking
• Postictal: prolonged lethargy, confusion, somnolence, may have pathologically brisk reflexes
• Injury from falls, shoulder dislocation, tongue biting
• Bradley and Daroff's Neurology, p. 38

Focal Seizures

• Manifestations depend on the brain region involved:
  • Frontal lobe: tonic posturing, complex motor automatisms
  • Temporal lobe: lip smacking, oral/alimentary automatisms, fear, deja vu
  • Parietal lobe: contralateral paresthesia
  • Occipital lobe: visual symptoms (flashes, scotoma)
• Jacksonian march: motor spread along contiguous motor cortex
• Todd's paralysis: transient postictal weakness in the region affected by a focal motor seizure
• Frameworks for Internal Medicine, p. 561

Provoked Seizure Causes (mnemonic: VITAMINS)

• Vascular: stroke, hypertensive encephalopathy, PRES, cerebral venous thrombosis
• Infectious: meningitis, encephalitis, brain abscess
• Toxic/drug-related: alcohol withdrawal, cocaine, bupropion, isoniazid, theophylline
• Autoimmune/Inflammatory: anti-NMDA receptor encephalitis, lupus cerebritis
• Metabolic: hypo/hypernatremia, hypoglycemia, hypocalcemia, hypomagnesemia, hepatic/uremic encephalopathy
• Idiopathic/Structural: tumors, head trauma, AVM
• Neoplastic

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4. Workup

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5. Chronic Pharmacologic Management (Anti-Seizure Medications)

First-Line Agents by Seizure Type

Common Agent Summary

• Try monotherapy first; combine only after multiple monotherapy failures
• Seizure control + side effects matter more than drug levels alone
• Levetiracetam and lamotrigine are safest in pregnancy (valproate is contraindicated)
• Textbook of Family Medicine, 9e, p. 1229-1230; Katzung's Basic and Clinical Pharmacology, 16th Edition

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6. Non-Pharmacologic Treatment

• Lifestyle: avoid sleep deprivation, limit alcohol, identify/avoid triggers (flashing lights, hyperventilation, stress, fever, certain drugs)
• Epilepsy surgery: temporal lobe resection is the most common (for mesial temporal lobe epilepsy); cortical resection for lesion-associated focal epilepsy
• Vagus nerve stimulator (VNS): for drug-refractory focal seizures; continuous open-loop stimulation
• Responsive neurostimulator (RNS): closed-loop device; detects abnormal EEG pattern and delivers stimulation
• Deep brain stimulation (DBS): bilateral anterior nuclei of thalamus; adjunctive for focal seizures
• Ketogenic diet: high-fat, low-carbohydrate; effective especially in pediatric refractory epilepsy
• Katzung's Basic and Clinical Pharmacology, 16th Edition

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7. Status Epilepticus (SE)

Step-by-Step Management Protocol

┌────────────────────────────────────────────────────────────┐
│  0-5 min: STABILIZE                                        │
│  • Airway: position, O2, suction; nasopharyngeal airway    │
│  • Monitoring: HR, BP, SpO2, temperature                   │
│  • IV/IO access; blood glucose (give D50 if hypoglycemic)  │
│  • Labs: electrolytes, glucose, Ca, Mg, CBC, LFTs,         │
│    tox screen, AED levels                                  │
│  • Correct metabolic abnormalities                         │
└────────────────────────────────────────────────────────────┘
          ▼
┌────────────────────────────────────────────────────────────┐
│  5 min: FIRST-LINE - Benzodiazepines                       │
│  • Lorazepam IV 0.1 mg/kg (max 4 mg) - PREFERRED          │
│    OR Diazepam IV 0.15-0.2 mg/kg                          │
│  • If no IV: intranasal/buccal/IM midazolam                │
│    (IM midazolam 10 mg for adults ≥40 kg)                  │
│  • Terminate seizure in ~70% of cases                      │
└────────────────────────────────────────────────────────────┘
          ▼ (if seizure continues at 5 min after 1st BZD)
┌────────────────────────────────────────────────────────────┐
│  Repeat benzodiazepine (second dose)                       │
└────────────────────────────────────────────────────────────┘
          ▼ (if seizure continues 5 min after 2nd BZD)
┌────────────────────────────────────────────────────────────┐
│  SECOND-LINE (equal efficacy):                             │
│  • Levetiracetam IV 60 mg/kg (max 4500 mg)                 │
│  • Fosphenytoin IV 20 mg PE/kg (max 1500 mg PE)            │
│    - Water-soluble, IM-compatible, less cardiotoxic        │
│    than phenytoin                                          │
│  • Valproic acid IV 40 mg/kg (max 3000 mg)                 │
│    - Avoid in liver disease, thrombocytopenia,             │
│    suspected metabolic disease                             │
└────────────────────────────────────────────────────────────┘
          ▼ (if refractory)
┌────────────────────────────────────────────────────────────┐
│  REFRACTORY SE - Intubation + ICU                          │
│  • Propofol, midazolam, or pentobarbital infusion          │
│  • Consider ketamine (case report evidence)                │
│  • Continuous EEG monitoring essential                     │
└────────────────────────────────────────────────────────────┘

• Rosen's Emergency Medicine, p. 169

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8. Special Situations

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9. When to Refer to Neurology

• Any first unprovoked seizure (for EEG/MRI workup)
• Seizures not controlled after 2 monotherapy trials
• Consideration of epilepsy surgery
• Pregnancy in a known epileptic
• Suspected epilepsy syndrome (e.g., juvenile myoclonic epilepsy, Lennox-Gastaut)

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• Frameworks for Internal Medicine, pp. 558-562
• Bradley and Daroff's Neurology in Clinical Practice, pp. 38, 510-512
• Katzung's Basic and Clinical Pharmacology, 16th Edition, pp. 637-649
• Rosen's Emergency Medicine, pp. 1985-1992, 169
• Textbook of Family Medicine, 9e, pp. 1228-1232
• Adams and Victor's Principles of Neurology, 12th Edition, p. 333