What is epilepsy?
Many people will have one seizure at some stage in their lives, but this is not necessarily epilepsy because there is a low risk of recurrence. Many children with epilepsy will eventually ‘grow out of it’ by the time they reach adulthood. For some people, the tendency to recurrent seizures may be a lifelong predisposition.
The International League Against Epilepsy (ILAE) classifies epilepsy as a disease of the brain that can be defined by the presence of any of the following conditions:
- At least two unprovoked (or reflex) seizures occurring more than 24 hours apart.
- One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years.
- Diagnosis of an epilepsy syndrome.
Syndromes are identified by the type of seizure/s, the age at onset, the EEG pattern and the pattern the seizures follow. They are sometimes associated with other underlying conditions. Identifying a seizure syndrome may be useful as sometimes this allows the most appropriate medication to be prescribed.
How is epilepsy diagnosed?
There are many stages in the diagnostic process. It is extremely important to get a correct diagnosis and this may need lots of tests and take considerable time. Questions need to be answered, such as:
- Is it epilepsy or is it something else?
- If it is epilepsy, what sort of epilepsy is it?
- Where does it start in the brain?
- Is there any structural abnormality in the brain?
What is needed for correct diagnosis?
- A full clinical history and a good description of the seizure/s;
- A physical and neurological examination;
- Investigations that may include an EEG recording and a CT scan or MRI brain scan.