Epilepsy: An Overview of Types

Epilepsy is a neurological disorder characterised by the propensity for recurrent, unprovoked seizures, which are transient occurrences of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain. The disorder encompasses a spectrum of conditions with varying aetiologies, clinical presentations, and seizure types.

The primary classification of epilepsy is determined by the type of seizure, which is categorised into two main groups:

• Focal Seizures: Originating within networks limited to one hemisphere. These are subdivided based on the level of consciousness:
  • With Retained Awareness: Formerly known as simple partial seizures.
  • With Impaired Consciousness: Previously referred to as complex partial seizures.
  • Evolution to Bilateral Tonic-Clonic Seizures: Presenting with a progression of muscle rigidity followed by rhythmic muscle contractions.

• Generalised Seizures: Engaging networks distributed across both hemispheres simultaneously. Types include:
  • Absence Seizures: Manifest as brief lapses in awareness.
  • Myoclonic Seizures: Characterised by sudden, brief muscle jerks.
  • Tonic-Clonic Seizures: Known for convulsive movements.
  • Atonic Seizures: Leading to sudden loss of muscle tone.

Epilepsy can also be categorised based on its aetiology, such as:

• Structural
• Genetic
• Infectious
• Metabolic
• Immune
• Unknown Causes

These aetiologies significantly influence the treatment and management of the condition.

In addition to seizure type and aetiology, epilepsy syndromes are recognised by a cluster of features that occur together, which can include:

• Specific Seizure Types
• EEG Findings
• Age of Onset

This concept is instrumental in directing specific management strategies.