After completing this module, you should be more aware of:

• Some of the main seizure types seen in people with epilepsy

• Some of the clinical features of different types of seizure

• The importance of correct identification of seizures for optimal management

• The definition of drug-resistant epilepsy

• Factors to consider when choosing a drug for seizure treatment

• Warnings and precautions to take when using certain antiseizure drugs

Epilepsy is a neurological syndrome characterised by seizures that originate in the brain.¹ The International League Against Epilepsy’s most recent update of its classification of epileptic seizures includes 21 different seizure types under four classes:^2,3,4

– Focal

– Generalised

– Unknown (whether focal or generalised)

– Unclassified

Consciousness is part of the classification of seizures and is determined by two factors: ability to recall the event and whether or not the person with epilepsy can respond normally during a seizure.⁴ 

The type of seizure a person has is determined largely by their description of the experience and observations of them during a seizure, if available. Other tests such as EEG, neuroimaging and laboratory tests may add to that information and influence the classification. So seizure classification depends on context and can change over time.⁴

Generalised seizures are more often seen in children and adolescents. They rarely start in people aged over 25 years although can continue to affect people when they become adults. Focal seizures are more common in adults. When there is insufficient information about a seizure to decide whether it is generalised or focal it is classified as unknown. And when no meaningful information about a seizure is available but a clinician is sure the likely cause is epilepsy then they are termed unclassified. The unknown and unclassified categories can be changed as and when more information about the seizures becomes available.⁴

Generalised seizures are grouped into absence seizures, generalized tonic-clonic seizures and other generalized seizures.^4,5 Focal and unknown seizures are further classified according to whether a patient’s state of consciousness is preserved or impaired.⁴ 

It should be remembered that not all seizures are caused by epilepsy¹ and it is important to understand that differentiating between seizures that are caused by epilepsy and those that have other causes is paramount to ensuring that appropriate treatment is offered.