Idiopathic Epilepsy

• A seizure is a brain disorder which manifests as paroxysmal cerebral dysrhythmia.
  • The episode has a sudden onset and ceases spontaneously.
  • Seizures tend to recur.
• In epilepsy, individuals appear to have a low seizure threshold.
  • This predisposes their neurons to depolarize of their own volition.
• "Idiopathic epilepsy" is said to occur when no other cause of seizuring is apparent.

Pathogenesis

• All seizures arise from a small group of neurons that periodically and spontaneously depolarize.
• In addition to being idiopathic (i.e. low seizure threshold), this sudden, uncontrolled neuronal discharge can occur due to:
  • Structural causes
    • Neoplasms
    • Inflammation
    • Trauma
  • Biochemical causes
    • Hypocalcaemia
    • hypoglycaemia
    • Hepatic encephalopathy.

• Idiopathic epilepsy is a relatively common cause of generalised seizures in the dog.
  • NOT in the cat.
• The onset of seizures is between 1 and 5 years of age.
• The condition presents as recurrent, unprovoked seizures, with no specific cause.
• There are no neurological defects between episodes.
• Seizures tend to start as generalised seizures, with no aura.