Once you have had a
seizure, it can be difficult to predict whether you
will have more seizures. This makes it hard to decide whether to begin
treatment for epilepsy. The first seizure you report may not actually be the
first seizure you've had. You may have had seizures in the past, such as brief
absence seizures or auras, without knowing they were
seizures.
Doing an
electroencephalogram (EEG), especially within 24 hours
of the seizure or after sleep deprivation, may reveal abnormalities in the
brain's electrical activity that may help confirm the diagnosis of epilepsy.
Often done routinely after first seizures,
CT and
MRI scans can be helpful in detecting changes in the
brain that could be related to epilepsy. Imaging scans may be done under other
circumstances, too. These tests may be done immediately if the person who has
had the seizure also has a decreased level of consciousness or new motor or
sensory problems that do not improve shortly after the seizure ends, or if the
person has ongoing headache or fever,
AIDS, recent trauma (especially to the head), or a
history of cancer or
anticoagulant therapy. These factors increase the
likelihood that the seizure may have been related to a serious problem in the
brain. The nature of the seizure and the person's age can also help determine
whether an imaging test is needed and how soon it is needed.
When making decisions about treatment, your doctor will consider how
likely you are to have a second seizure. (The overall risk of epilepsy in the
general population is about 1 in 100.) Risk factors for having a second seizure
include:
- Evidence of a structural lesion in the brain as
seen on a CT or MRI scan (if one is done) or the likelihood of a lesion as
suggested by your symptoms and history.
- Abnormal EEG
results.
- A family history of seizures or
epilepsy.
- Partial seizure.
There is some evidence to support the use of antiepileptic medicines
after a first seizure to reduce the risk of additional seizures. But medicine
is usually not prescribed if you do not have any of the above risk factors and
are thought to be unlikely to have additional seizures. Taking antiepileptic
medicines when you are not at risk for additional seizures exposes you to
unnecessary side effects and potential harm from the medicine.