Epilepsy is a disorder that has many causes. We can classify them as known, identifiable causes, or as causes of unknown origin.


1) Identifiable cause: due to a brain lesion or malformation. This type of epilepsy is called symptomatic epilepsy and it can usually be detected by a magnetic resonance imaging (MRI) or by biopsy (study under microscope of brain tissue).

Among the main causes are to be found:

  • Perinatal brain injury by hypoxia (fetal suffering, low birth weight, premature delivery)
  • Congenital brain malformations
  • Traumatic brain injury
  • Stroke
  • Brain infections such as meningitis and encephalitis.
  • Brain tumors.

When epilepsy is caused by identifiable lesions on  magnetic resonance imaging (MRI), and the seizures are resistent to medication, there is a clear indication for a presurgical workup.

Many of these symptomatic, drug resistant epilepsies need surgical intervention.


2) No identifiable cause: when epilepsy does not have an obvious cause, and the brain MRI appears normal. This is the more frequent type, in 6 out of 10 cases.

  •  Idiopathic epilepsy: due to genetic causes.
  • Cryptogenic epilepsy: an organic brain lesion is highly suspected, but not found on neuroimaging.

Epilepsy is more frequent in childhood and in old age.



Symptoms might vary depending on the patient and the brain area where the disorder starts up.

The main symptoms are::

  • Episodic loss of consciousness.
  • Muscle spasms, jerks or convulsive movements.
  • Before the seizure starts, strange feelings, sights or mental perceptions may happen. This phenomenon is called an aura.

It is important to point out that to make a diagnosis of epilepsy, at least two unprovoked seizures are needed.