Generalised symptomatic 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. Symptomatic is a medical term meaning that there is some structural abnormality in the brain, either present at birth or occurring later in life. Other disabilities may be caused by this same abnormality (physical, intellectual or psychiatric). EEG investigations may reveal the abnormality and the response to drug treatment is variable in different individuals. (Some individuals have cryptogenic epilepsy, which is epilepsy in which no cause can be found, even though a cause is suspected.)


Infantile spasms (West syndrome)

Infantile spasms are a particularly harmful form of epilepsy, which can result in mental and physical retardation unless brought under control rapidly. The primary distinguishing feature of infantile spasms are clusters of myoclonic spasms - the jerking of one or more limbs.

Neurologists believe that it is important to identify infantile spasms as early as possible, in order to try to minimise the damage that they cause. The difficulty is that while the myoclonic spasms are very characteristic, they may initially be very subtle and difficult to recognise.

The prognosis for infantile spasms is poor. The spasms usually remit spontaneously after a few months, often to be replaced by other forms of epilepsy before the age of 5

  • applied to the triad of hypsarrhythmia, mental retardation and infantile spasms
  • Infantile spasms refers to brief atonia followed by tonic contraction of the axial and proximal limb muscles
  • onset before the age of 1 year (peak 4 to 7 months)
  • divided into symptomatic and idiopathic groups

    Lennox-Gastaut syndrome

    Lennox-Gastaut syndrome is the most distressing of childhood epilepsies. The children suffer frequent fits of many different types, and experience gradual mental deterioration. Infantile spasms often evolve into Lennox-Gastaut syndrome, and the age of onset is from 1 to 8 years, peaking at 3 to 5 years. The prognosis for children with Lennox-Gastaut syndrome is bleak.

    Lennox-Gastaut syndrome is characterised by multiple types of fit. As well as drop attacks, these are likely to include atypical absence fits and massive myoclonic jerks. Atypical absence fits may begin and end gradually, with consciousness only partially affected; the child may continue to be active, although mentally distant and abstracted. Myoclonic jerks are the violent jerking of one or more limbs.

  • this label is often used loosely for intractable epilepsy in childhood
  • key components are: specific fit types which are difficult to control, specific interictal and ictal EEG abnormalities and diffuse cognitive dysfunction
  • tonic and atypical absence fits are the most frequent fit types
  • atonic fits are rare but the label is abused for fits where falls occur
  • clinical fits begin at about the age of 2 years
  • typical EEG pattern may not be seen till 3 or 4 years of age
  • slow spike and wave complexes or multifocal independent sharp waves
  • mental retardation may evolve with time, not all patients are mentally retarded
  • rigorous classification of this syndrome is difficult

    Progressive myoclonus epilepsies


    return to   Types of epilepsy



    (checked: 15 November 2002)
    (update 1.1: 18 July 2002)
    (issue 1: 24 March 1998)