Makindo Medical Notes

⚡ Seizure Classification (ILAE 2017)

• Focal onset seizures
  • Start in one hemisphere.
  • Defined by awareness at onset:
    • Focal aware → patient remains conscious (previously "simple partial").
    • Focal impaired awareness → awareness impaired (previously "complex partial").
  • Can evolve to bilateral tonic-clonic seizure (old term: “secondary generalisation”).
  • Symptoms reflect cortical origin → temporal lobe (déjà vu, automatisms), occipital (visual flashes), frontal (motor phenomena).
• Generalized onset seizures
  • Involve both hemispheres from the start.
  • Motor types: tonic-clonic, clonic, tonic, myoclonic, atonic.
  • Non-motor: absence seizures (typical, atypical, or with special features).
  • Often have a strong genetic basis (e.g. childhood absence epilepsy, juvenile myoclonic epilepsy).
• Unknown onset seizures
  • Onset not observed (e.g. nocturnal seizures, unwitnessed falls).
  • Provisional category — can be reclassified when further history/EEG is obtained.

🧠 Epilepsy Classification (ILAE 2017)

Epilepsies are classified at three levels: seizure type, epilepsy type, and, where possible, syndrome.

• Focal epilepsy – seizures arise from one hemisphere.
  • Examples: mesial temporal lobe epilepsy, post-stroke focal epilepsy.
• Generalized epilepsy – seizures involve both hemispheres from onset.
  • Examples: childhood absence epilepsy, juvenile myoclonic epilepsy.
• Combined generalized and focal epilepsy – both seizure types present.
  • Example: Dravet syndrome.
• Unknown epilepsy – insufficient evidence to classify.

🧬 Epilepsy Aetiology Framework

The ILAE also recognises causes, which guide prognosis and treatment:

• Structural – e.g. cortical dysplasia, stroke, tumour.
• Genetic – inherited or de novo channelopathies (e.g. SCN1A mutations).
• Infectious – e.g. neurocysticercosis, encephalitis.
• Metabolic – e.g. mitochondrial disorders.
• Immune – e.g. autoimmune encephalitis.
• Unknown – no cause yet found.