What Are The Causes of Epilepsy

What is it that makes neurones of the brain discharge abnormally? No cause can be determined for about three-quarters of the cases of epilepsy. Because epilepsy has so many causes and can be linked to a number of other conditions, it is sometimes very difficult to determine the cause of a particular case. Anything that disturbs the normal pattern of activity in the brain can trigger epilepsy, they include:

An inherited instability in the functioning of neurones seems to be responsible for the common forms of generalised epilepsy, especially absence attacks, and tonic-clonic seizures where there is a family history of similar disorder. How this genetic defect operates has yet to be established - perhaps the abnormality lies in the structure of the neurone's outer membrane, leading to electrical instability.

Injury to the brain may certainly cause epilepsy. This includes deprivation of oxygen at birth, trauma to the head at any time of life, and stroke (injury to part of the brain caused by blockage or haemorrhage of one of its blood vessels).

Metabolic disturbance can produce generalised seizures through disturbing the normal functioning of neurones. This may occur when there is severe lowering of blood glucose levels, and when there is severe malfunctioning of the liver or kidneys.

Alcohol and drug abuse may cause seizures during intoxication, or when the offending substance is being withdrawn. Withdrawal of certain medications, such as barbiturates and other sedatives, can cause epileptic seizures in those who have taken them for long periods.

Brain tumour is, fortunately, a relatively uncommon cause of epilepsy, but it must be excluded in all patients who develop epilepsy for the first time during adult life. Tumour should also be excluded in children and adolescents in whom the appearances of the EEG test (see below) are not typical of genetic epilepsy, or where these does not seem to be an adequate alternative explanation (such as birth injury).