Understanding Why
Causes
Epilepsy has many possible causes. Understanding the cause can help guide care, but not everyone receives a clear explanation for why their epilepsy developed.
About this information: This webpage is subject to continuous review by Epilepsy South Central Ontario to help keep the information current. Updates may be in progress. This material is for informational purposes only and should not be used for self-diagnosis or as a substitute for professional medical advice, diagnosis or treatment. Consult your healthcare provider about your own health and care.
The Main Categories
What can cause epilepsy?
The International League Against Epilepsy groups the causes of epilepsy into six categories. A person’s epilepsy may fit more than one category.
01 · Structural
Changes in brain structure
Epilepsy may be related to differences in brain development or changes caused by stroke, a brain injury, a tumour or another condition.
Brain imaging, together with other clinical information, may help identify a structural cause.
02 · Genetic
Genetic factors
Some epilepsies have a known or presumed genetic basis. This may involve a single genetic change or the combined effects of several genes.
Genetic does not always mean inherited. A genetic change may occur for the first time in a person rather than being passed down from a parent.
03 · Infectious
Infections affecting the brain
Certain infections, including meningitis or encephalitis, can lead to epilepsy.
An infection can also cause seizures during an acute illness. That does not automatically mean the person has epilepsy.
04 · Metabolic
How the body processes substances
Some metabolic disorders can cause epilepsy by affecting processes the brain needs to function.
Identifying a specific metabolic cause may have important implications for treatment.
05 · Immune
Immune-related conditions
Some epilepsies are associated with immune system disorders affecting the brain, including certain autoimmune conditions.
Specialist assessment may identify whether immune-related investigations or treatment are appropriate.
06 · Unknown
When the cause is not identified
Sometimes the underlying cause remains unknown, even after investigation. “Unknown” describes what is currently understood; it does not mean the epilepsy is not real.
Your healthcare provider can explain what has been investigated and whether further assessment may be useful.
More than one category can apply.
For example, a genetic condition may also cause a structural difference in the brain. The categories are not competing explanations: together, they can help describe a person’s epilepsy and guide care.
An Important Difference
Causes and triggers are not the same.
A cause helps explain the condition.
The cause is the underlying reason a person has epilepsy, such as a genetic factor or a structural change in the brain.
A trigger can influence seizure timing.
A trigger is a circumstance that may make a seizure more likely for a particular person, such as sleep deprivation. Having a possible trigger does not, by itself, explain why epilepsy developed.
Your Healthcare Conversation
Questions you can ask.
- What is currently known about the cause of my epilepsy?
- Could more than one cause category apply?
- Would further imaging, genetic testing or other investigations be useful?
- Would identifying a cause change my treatment or follow-up?
- If a genetic cause is suspected, would genetic counselling be helpful?
The appropriate investigations depend on your history and clinical circumstances. Not everyone needs every test.
Further reading:
ILAE Classification of the Epilepsies ·
ILAE: Epilepsy and Genetics.