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Comprehensive Guide to Seizures and Epilepsy

May 18, 2025

Lecture Notes: Seizures, Epilepsy, and Status Epilepticus

Introduction

  • Definitions
    • Seizure: Abnormal, excessive, synchronous electrical activity in the CNS.
    • Epilepsy: Two unprovoked seizures >24 hours apart or one with a 60% recurrence rate.
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Causes of Seizures

  • Remember the mnemonic VITAMIN D and E.

Vascular Causes

  • Acute ischemic stroke
  • Intracerebral hemorrhage
  • Subarachnoid hemorrhage
  • Hypertensive encephalopathy: If with vasogenic edema, called PRES.
  • Anoxic brain injury

Infectious Causes

  • Meningitis: Irritation near cortex.
  • Encephalitis
  • Brain abscess

Traumatic Causes

  • Epidural hematoma: Lens-shaped.
  • Subdural hematoma: Crescent-shaped.

Autoimmune Causes

  • Autoimmune encephalitis
  • Systemic lupus erythematosus
  • Paraneoplastic syndromes

Metabolic Causes

  • Thiamine deficiency: Wernicke's encephalopathy.
  • Hypoglycemia/Hyperglycemia
  • Hyponatremia/Hypernatremia
  • Hypocalcemia
  • Hypomagnesemia
  • Hypophosphatemia
  • Uremia (kidney)
  • Liver failure
  • Hyperthyroidism

Idiopathic Causes

  • Epilepsy syndromes (e.g., West syndrome, Lennox-Gestaut syndrome, Juvenile myoclonic epilepsy).

Neoplasia

  • Glioblastoma multiforme
  • Meningiomas
  • Metastatic malignancies

Drug Causes

  • Remember Otis Campbell mnemonic: Opioids, TCAs, Anticholinergics, Isoniazid, Salicylates, etc.
  • Eclampsia
  • Febrile seizures

Pathophysiology of Seizures

  • Glutamate pathway: Increase leads to more action potentials.
  • GABA pathway: Decrease in inhibitory action leads to seizures.

Types of Seizures

Focal Seizures

  • With impairment: Involves the thalamus and reticular formation.
  • Without impairment: No thalamus/reticular formation involvement.
  • Motor symptoms: Tonic, clonic, myoclonic, Jacksonian march.
  • Sensory symptoms: Pain, paresthesia, visual/auditory hallucinations.
  • Autonomic symptoms: Tachycardia, hypertension, urinary incontinence.
  • Psychological symptoms: Emotional changes, déjà vu, depersonalization.

Generalized Seizures

  • Motor (Convulsive)
    • Types: Tonic, clonic, myoclonic, tonic-clonic (grand mal).
    • Symptoms: Loss of consciousness, tonic-clonic jerking, screaming, tongue biting, incontinence.
  • Non-Motor (Absence)
    • Symptoms: Brief staring, daydreaming, no postictal state.

Diagnostics

  • History: Check for epilepsy and anti-epileptic drug levels.
  • Imaging: CT, MRI, lumbar puncture.
  • Laboratory tests: CBC, blood cultures, electrolyte panels, autoimmune panels.
  • EEG: Look for epileptic activity, especially for absence seizures (3 Hz spike and wave).
  • Additional labs: CK, lactate, prolactin, troponin, EKG for arrhythmias.

Treatment

  • Anti-Epileptic Drugs (AEDs)
    • Sodium channel blockers: Valproate, Phenytoin, etc.
    • Calcium channel blockers: Gabapentin, Ethosuximide (absence seizures).
    • SV2A blockers: Levetiracetam.
    • NMDA receptor blockers: Ketamine.
    • GABA agonists: Benzodiazepines, Propofol, Phenobarbital.
    • GABA reuptake inhibitors: Tiagabine.
    • GABA transaminase inhibitors: Vigabatrin, Valproate.

Status Epilepticus Treatment

  • Definition: Seizure >5 mins or recurrent seizures without return to baseline.
  • Management: ABCs, reverse reversible causes (e.g., D50, Thiamine).
  • Medications: Benzodiazepines, IV anti-epileptics (Propofol, Midazolam, Ketamine).
  • Maintenance: Continue AEDs if underlying cause is not reversible.

This covers the key points and details on seizures, epilepsy, and related treatments, providing a comprehensive guide for review and study.

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