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occur in approximately 3% of people with epilepsy but it is most common in patients with
severe epilepsy who are non-compliant with drug therapy. It may also occur in alcohol
withdrawal, in acute meningitis or encephalitis, and in acute metabolic disturbances.

Nonconvulsive status
This term is used imprecisely for the following two very different scenarios:

a) Motor manifestations in convulsive status inevitably cease at some point, however the
cerebral cortex may continue to generate ictal discharges (‘no longer convulsive status
epilepticus’). This represents the most severe form of status, with ongoing excitotoxicity on
a cellular level and high morbidity and mortality from a clinical perspective.

b) Ictal activity that from the onset was not associated with motor manifestations. Usually,
the leading symptom is a change in the patient’s cognitive state (confusion, disorientation
with subsequent amnesia). This kind of status epilepticus is thought to have focal origin,
though this may no longer be evident once the ictal activity has been ongoing.

Focal status
The ongoing seizure activity that defines status epilepticus may be restricted to a confined
brain area. In this setting, the ictal symptoms reflect the cortical area affected (e.g. aura
continua, aphasia). One classic example is epilepsia partialis continua of Kojevnikov. This
refers to repetitive jerking of muscles or muscle groups in the face, arm or leg, originally
described in association with epidemic encephalitis in Russia. Nowadays, the most common
aetiologies are vascular disease, Rasmussen encephalitis, and tumours.

Relative frequency of seizure types

Data on the relative frequency of seizure types is unsatisfactory, and is largely based on
populations of patients with relatively severe epilepsy, including large numbers of patients
with partial epilepsies. Furthermore, the milder the epilepsy the more difficult it is to
determine on clinical and electroencephalographic grounds whether it is of primary
generalised or partial type. With these restrictions in mind, most series would suggest that
approximately one-third of epilepsies may be of a generalised type, while two-thirds are
partial, most commonly with a temporal lobe origin.

References

1. Commission on Classification, International League Against Epilepsy (1981) Proposed provisions of clinical and
electroencephalographical classification of epileptic seizures. Epilepsia 22, 489-501.

2. ENGEL J Jr. (2006) Report of the ILAE classification core group. Epilepsia 47, 1558-1568.
3. ENGEL J Jr. (2001) A proposed diagnostic scheme for people with epileptic seizures and with epilepsy: report of

the ILAE Task Force on Classification and Terminology. Epilepsia 42, 796-803.
4. BERG AT, BERKOVIC SF, BRODIE MJ et al (2010) Revised terminology and concepts for organisation of

seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 20052009. Epilepsia
51, 676-685.
5. PANAYIOTOPOULOS CP (2011) The new ILAE report on terminology and concepts for organization of epileptic
seizures: A clinician’s critical view and contribution. Epilepsia 52, 2155-2160.
6. SHORVON S (2011) The etiologic classification of epilepsy. Epilepsia 52, 1052-1057.
7. LÜDERS H, AMINA S, BAUMGARTNER C et al (2012) Modern technology calls for a modern approach to
classification of epileptic seizures and the epilepsies. Epilepsia 53, 405-411.
8. WIEBE S, LÜDERS HO, MIZRAHI E et al (2001). Glossary of descriptive terminology for ictal semiology: report
of the ILAE task force on classification and terminology. Epilepsia 42, 1212-1218.