Generalised idiopathic epilepsies  




Generalised epilepsies are those which have no defined focal area within the brain; as a result they have generalised symptoms as the whole brain becomes affected. Idiopathic is a medical term meaning that there is no clear environmental cause for the epilepsy and it is presumed that genetic factors predominate. There are usually no other handicaps and the EEG is often normal between fits. The response to drug treatment is usually good.

Benign myoclonic epilepsy in infants

Juvenile myoclonic epilepsy

  • most common primary / idiopathic generalized epilepsy
  • onset from 8 to 30 years (mean 14 years)
  • myoclonic, absence and generalized tonic clonic fits
  • fits occur on awakening
  • sleep deprivation, alcohol or menstrual periods may be precipitants
  • Ictal EEG shows polyspikes followed by slow, irregular spike and wave complexes
  • photosensitivity is common
  • good response to valproic acid and clonazepam
  • Childhood absence epilepsy

  • uncommon (2 - 5%)
  • frequent absence fits with abrupt onset and termination
  • generalized tonic clonic fits are infrequent (<10%)
  • onset 3 to 12 years; peak 6 to 7 years, female preponderance
  • neurologically normal subject
  • 3Hz spike and wave complexes is the typical EEG abnormality
  • some develop generalised tonic clonic fits in adolescence or early adulthood
  • Juvenile absence epilepsy

  • absences tend to occur in clusters
  • age of onset 8 to 18 years, peak 13 years
  • more likely to present with generalised tonic clonic fits
  • more likely to have myoclonic fits
  • uncertain whether this is a distinct entity from childhood absence epilepsy
  • Epilepsy with generalised tonic clonic fits in childhood

  • about 1.5% of childhood epilepsy
  • rare generalised tonic clonic fits, typical total fit count is 5
  • good chance of remission
  • usually normal intellect (95% or greater)
  • onset occurs in association with febrile fits
  • return to   Types of epilepsy



    (checked: 15 November 2002)
    (update 1.1: 8 November 2002)
    (issue 1: 24 March 1998)