Seizures are caused by an abnormal impulse of electrical activity within the brain. The causes of seizures are quite varied and include:
- a tumour or blood in the brain
- scarring within the brain from surgery or radiotherapy
- high fevers
- some medications or drug withdrawal
- head trauma
There are many different types of seizures, which have a range of signs and symptoms. In general, seizures are of 2 types:
- Focal seizures are due to an abnormal electrical impulse that is confined to a small area of the brain. They can produce abnormal sensations, such as numbness or tingling; involuntary movement of a limb or twitching in the face; or transient inability to speak. The symptoms experienced by the person having the seizure relate to the location within the brain of the abnormal impulse. Therefore, a focal seizure tends to be experienced in the same way each time a person has one.
- Generalized seizures occur when the abnormal impulse is transmitted across a larger area of the brain. Consciousness is affected, and there may be convulsions and/or loss of bowel and bladder control. Often there is little or no memory of the seizure once it ends.
Seizures tend to last only 30 to 60 seconds. Focal seizures may evolve into generalized seizures.
Seizures are managed with seizure medications (antiepileptic drugs) that reduce the frequency and severity of seizures but may not eliminate them completely. Many people affected by seizures continue to work. There may be some restrictions on work activities, however. For example, there are legal implications regarding driving for those who have had a seizure or who stop taking seizure medications. Special precautions may need to be in place if employees operate heavy machinery, climb ladders, work on rooftops, cycle, scuba dive or perform other tasks that could be dangerous if they have a seizure.
See also this information about driving restrictions.