15.1.4 The causes of epilepsy
For most people — six out of ten, in fact - there is no known cause of epilepsy and this is called idiopathic epilepsy. But sometimes the reason epilepsy develops is clear. It could be because of a severe blow to the head, a stroke, or an infection of the brain such as meningitis. Epilepsy with a known cause is called symptomatic epilepsy. Epilepsy can also be caused by drug and alcohol misuse, by conditions that affect the structure of the brain, such as cerebral palsy, by birth defects or by problems during birth which cause a baby to be deprived of oxygen (such as the umbilical cord getting twisted, or compressed, during labour).
The causes of oxygen deprivation (hypoxia) in newborns is covered in the Labour and Delivery Care Module.
Sometimes children below five years of age can have a seizure when they have a high fever. This is called febrile convulsion. If epilepsy occurs for the first time after the age of 20 years, it is usually symptomatic epilepsy, due to detectable brain damage such as a scar or healed wound in the brain, bleeding inside the brain, or damage because of long-term, excessive use of alcohol.
The diagnosis of epilepsy is mainly based on the description of the seizure given by the person themselves and any eye witness accounts. Box 15.1 provides examples of some of the questions you should ask the person and their family after a seizure has taken place.
Box 15.1 Useful questions for assessing epileptic seizures
Questions to ask the person:
- How did you feel before you had the seizure, for example hot, cold, hungry, tired, etc.?
- Did you experience any unusual symptoms beforehand, for example, nausea, dizziness or chest pain?
- Had you drunk any alcohol or taken any drugs of any kind?
- Did you have any warning beforehand? If so, what?
- Do you remember anything about the seizure? If not, what happened when you came round?
- Did you fall over and/or injure yourself?
- Were there any symptoms after the seizure?
- How many seizures have you had?
- Are there any other factors which could suggest epilepsy, for example, head injury, previous seizures, other people in your family with epilepsy?
Questions to ask witnesses:
- What was the person doing when the seizure started?
- What exactly happened when they had the seizure?
- How long did the seizure last?
- Did they appear confused after the seizure?
A useful method for gaining insight into the recurrence of seizures is to encourage the person to keep a seizure diary (or mental record), noting the date, type of seizure, the time it occurred and its duration, and any thoughts they may have about possible epilepsy triggers or other relevant features.