Seizures and Epilepsy
Having a seizure does not necessarily mean a person has epilepsy, although the two are often linked. Cases where there is no relationship between the two include febrile seizures in children, seizures in pregnant women with eclampsia, and seizures caused by psychological factors. Conditions such as narcolepsy may cause symptoms that appear to be the result of seizures and epilepsy, but are caused by neither.
While any seizure is cause for concern, having a seizure does not by itself mean a person has epilepsy. Examples of seizures that may not be associated with epilepsy can include:
- First seizures
- Febrile seizures
Many people have a single seizure at some point in their lives. Often, these events occur in reaction to anesthesia or a strong drug, but they also may be unprovoked, meaning that they occur without any obvious triggering factor. Unless the person has suffered brain damage or there is a family history of epilepsy or other neurological abnormalities, these single seizures usually are not followed by additional seizures.
One recent study that followed patients for an average of eight years found that only 33 percent of people have a second seizure within four years after an initial seizure. People who did not have a second seizure within that time remained seizure-free for the rest of the study. For people who did have a second seizure, the risk of a third seizure was about 73 percent, on average, by the end of four years.
When someone has experienced a first seizure, the doctor will usually order an electroencephalogram, or EEG, to determine what type of seizure the person may have had and if there are any detectable abnormalities in the person's brain waves. The doctor also may order brain scans to identify abnormalities that may be visible in the brain.
These tests can help the doctor decide whether to treat the person with antiepileptic drugs. In some cases, drug treatment after the first seizure may help prevent future seizures and epilepsy. However, the drugs also can cause detrimental side effects, so doctors prescribe them only when they feel the benefits outweigh the risks.
Evidence suggests that it may be beneficial to begin anticonvulsant medication once a person has had a second seizure, as the chance of future seizures increases significantly after this occurs.