Seizures are common and are treated in all branches of medicine. Approximately 10% of the population will have one or more seizures during their lifetime. Seizures are symptoms that occur in acute illness, ie, provoked seizures, or in epilepsy, ie, unprovoked seizures. Epilepsy is any disorder in which spontaneous recurrence of unprovoked seizures is the main symptom. It is a common chronic neurologic disorder and affects 1% to 3% of the population.

Classification of seizure type is important because it enables identification of the region of the brain where the seizure originated and guides initial diagnostic testing. Classification of epilepsy syndrome, rather than only type of seizure, is more important. Epilepsy syndromes are defined by many factors, including type of seizures, age at onset of seizures, family history of seizures, and findings at physical examination, electroencephalography (EEG), and neurologic imaging studies. Identifying the epilepsy syndrome provides insight into natural history, prognosis, diagnostic testing, and therapy of the disorder and facilitates communication between health care professionals. Understanding seizure type provides useful information even when the epilepsy syndrome cannot be classified.

Many sudden events are easily confused with seizures, in particular, pseudoseizures, syncope, migraine, cerebrovascular disease, movement disorders, and sleep disorders. In most cases a detailed history and physical examination concentrated on the details of the event, and results of routine EEG and magnetic resonance imaging can aid in determination of which events are seizures. Video EEG monitoring is occasionally necessary to capture events to enable definitive determination of whether they are seizures and to further characterize them.

Provoked seizures are treated with relief of the provoking factor. Antiepileptic drugs (AEDs) are not indicated. However, AEDs may be required to treat unprovoked seizures of new onset in patients at high risk for seizure recurrence or when a second seizure can have devastating psychosocial effects. High risk for recurrence is present when there is a history of brain insult, an EEG demonstrates epileptiform abnormalities, and magnetic resonance images demonstrate a structural lesion.

AED therapy is the standard treatment for epilepsy, ie, two or more seizures. Selection of the appropriate AED depends on type of seizure and epilepsy present, and individual drug characteristics, including pharmacokinetics, side effects, dosing interval, and cost. All available AEDs except ethosuximide are effective as adjunctive therapy, and most are effective as initial monotherapy for partial seizures. Generalized seizures preferentially respond to valproate, lamotrigine, and topiramate, among other drugs. If trials of more than two AEDs do not control seizures, additional AEDs are unlikely to be effective, and the patient should be referred to an epilepsy center, where other treatment options, in particular, epilepsy surgery, can be offered. Epilepsy surgery renders 60% to 70% of patients with temporal lobe epilepsy free of disabling seizures.