Seizures and Epilepsy

Introduction

• Seizure Definition: Abnormal excessive synchronous electrical activity in the central nervous system leading to outward manifestations.

Causes of Seizures

Mnemonic: VITAMIN D and E

1. Vascular Causes:
   • Acute ischemic stroke
   • Intracerebral hemorrhage
   • Subarachnoid hemorrhage
   • Hypertensive encephalopathy / PRES (Posterior Reversible Encephalopathy Syndrome)
   • Severe anoxic brain injuries
2. Infectious Causes:
   • Meningitis
   • Encephalitis
   • Brain abscess
3. Traumatic Causes:
   • Epidural hematoma
   • Subdural hematoma
4. Autoimmune Causes:
   • Systemic lupus erythematosus (SLE)
   • Paraneoplastic syndromes
5. Metabolic Causes:
   • Thiamine (Vitamin B1) deficiency
   • Hypoglycemia (and less common hyperglycemia)
   • Hyponatremia (more common) / Hypernatremia
   • Hypocalcemia
   • Hypomagnesemia
   • Hypophosphatemia
   • Uremia
   • Liver failure (Ammonia buildup)
   • Hyperthyroidism
6. Idiopathic Causes:
   • Defined as epilepsy (≥ 2 unprovoked seizures >24 hours apart or 1 unprovoked seizure with a 60% recurrence rate)
   • Non-compliance or sub-therapeutic dose of anti-epileptic drugs
   • Epilepsy syndromes (West syndrome, Lennox-Gastaut syndrome, Juvenile myoclonic epilepsy)
7. Neoplasia:
   • Glioblastoma multiforme
   • Meningioma
   • Metastatic brain tumors
8. Drug Causes: Mnemonic: OTIS CAMPBELL
   • Opioids, Tricyclic antidepressants, Anticholinergics, Isoniazid, Salicylates, Cocaine, Cefepime, Amphetamines, Metronidazole, Penicillins, Benzodiazepine withdrawal, Bupropion, Ethanol withdrawal, Lithium
9. Eclampsia:
   • Pregnant women
   • High blood pressure
   • Seizures

Other Causes

• Fevers (esp. children with Roseola)
• Genetic disorders

Pathophysiology

• Increased stimulatory glutamate pathway (NMDA, AMPA receptors → more cations → depolarization → action potentials)
• Decreased inhibitory GABA pathway (GABA-A receptors → chloride ions → hyperpolarization → decreased action potentials)
• Focal seizures vs. generalized seizures
  • Focal: One hemisphere
  • Generalized: Bilateral hemispheres

Clinical Features

Phases of Seizure

1. Trigger: Stress, sleep deprivation, bright lights/sounds, vitamin D and E causes
2. Aura: Deja vu, impending fear, nausea, automatisms (e.g., rapid blinking, chewing, lip smacking)
3. Ictal Event: Visible seizure activity (focal or generalized)
4. Post-ictal Phase: Confusion, lethargy, amnesia, Todd's paralysis

Types of Seizures

Focal Seizures

• Motor: Tonic, clonic, myoclonic, Jacksonian march (distal to proximal spread)
• Sensory: Pain, paresthesias, visual/auditory/olfactory/gustatory hallucinations
• Autonomic: Tachycardia, hypertension, urinary incontinence, salivation, sweating
• Psychological: Emotional changes, hypersexual behavior, deja vu, depersonalization, derealization

Generalized Seizures

• Motor: Tonic-clonic (Grand mal), Atonic, Clonic, Tonic, Myoclonic
  • Features: Respiratory cry, up gaze, pooling of oral secretions, tongue biting, incontinence, tachycardia, hypertension
• Non-motor: Absence (Petit mal)
  • Features: Staring, daydreaming, rapid blinking, lip smacking, no post-ictal state
  • Diagnostic Indicator: EEG shows 3 Hz spike and wave pattern

Diagnosis

• History of Seizures: Assess AED (Anti-Epileptic Drug) levels
  • If low: Increase dose
  • If normal: Adjust or switch AED
• First-time Seizure:
  • Vascular: CT, MRI, Lumbar puncture
  • Infectious: CT, MRI, Lumbar puncture, Blood cultures, CBC
  • Trauma: CT scan for hematomas
  • Autoimmune: Autoimmune panel, CT chest/abdomen/pelvis
  • Metabolic: Check B1, glucose, BMP + Mg/Phos, TSH with reflex, ammonia, liver function
  • Idiopathic: Evaluate AED compliance
  • Neoplasia: CT, MRI with contrast
  • Drugs: Review med list, toxicology screen
  • Eclampsia: Urine/serum beta HCG
  • Others: Temperature, genetic testing
• Additional Labs: CK, Lactate, Prolactin, Troponin, EKG
• EEG: Essential to check for abnormal electrical activity

Treatment

• Initial Management: ABCs (Airway, Breathing, Circulation), reverse easy causes, benzodiazepines
• Status Epilepticus:
  • Seizure > 5 mins or multiple seizures without recovery
  • ABCs, reverse easy causes, benzodiazepines (Lorazepam IV, Midazolam IM)
  • Proceed with AED loading (Levetiracetam, Phenytoin, Fosphenytoin, Valproate)
  • Continue with IV anti-epileptics (Propofol, Midazolam, Ketamine, Pentobarbital)
  • Add maintenance doses of AED
  • Consider ketogenic diet and further workup if seizures persist
• Note: Continual assessment and management based on patient status and underlying cause