Epilepsy is a chronic disease marked by recurrent unprovoked seizures. A person is diagnosed with epilepsy if they have two unprovoked seizures (or one unprovoked seizure with the likelihood of more) that were not caused by some known and reversible medical condition like alcohol withdrawal or extremely low blood sugar. The seizures in epilepsy may be related to brain injury or genetics, but the cause is often completely unknown. The word "epilepsy" does not indicate anything about the cause of the person's seizures or their severity.1,2
Many people with epilepsy have more than one type of seizure and may also have other neurological symptoms. An epilepsy syndrome combines information about seizure types with information about the neurological findings, genetics and family history, EEG (brain wave) picture, brain imaging studies, and other specialised lab studies. The syndrome is important for guiding optimal treatment and determining prognosis. A few common epilepsy syndromes are localisation related (focal) epilepsy, childhood or juvenile absence epilepsy, juvenile myoclonic epilepsy, epileptic (infantile) spasms, Lennox-Gastaut syndrome, and Dravet syndrome.
Although the symptoms of a seizure may affect any part of the body, the electrical events that produce the symptoms occur in the brain. The location of that event, how it spreads, how much of the brain is affected, how long it lasts, and the maturity of the brain all have profound effects. These factors determine the character of a seizure and its impact on the individual.
Seizures and epilepsy can affect one's safety, relationships, work, driving, and so much more. Public perception and attitude of people with epilepsy are often bigger problems than the seizures themselves.
There are three major groups of seizures:
1. Generalised onset seizures: These seizures affect both sides of the brain (or groups of cells on both sides of the brain) at the same time. This term includes seizures types like tonic-clonic, absence, or atonic seizures.
2. Focal onset seizures: The term focal is used instead of partial to be more accurate when talking about where seizures begin. Focal seizures can start in one area or group of cells in one side of the brain.
Within the category of focal onset seizures, a person may experience a focal onset aware seizure (when they are awake and aware during the seizure, formerly called a simple partial seizure) or a focal onset impaired awareness seizure (when a person is confused or their awareness is affected in some way during the seizure, formerly called a complex partial seizure).
3. Unknown onset seizures: When the beginning of a seizure is not known, it’s now called an unknown onset seizure. A seizure could also be called an unknown onset if it’s not witnessed or seen by anyone, for example when seizures happen at night or in a person who lives alone. As more information is learned, an unknown onset seizure may later be diagnosed as a focal or generalised seizure.
Many different symptoms happen during a seizure and may vary depending on the seizure type.
For generalised onset seizures:
Motor symptoms may include sustained rhythmical jerking movements (clonic), muscles becoming weak or limp (atonic), muscles becoming tense or rigid (tonic), brief muscle twitching (myoclonus), or epileptic spasms (body flexes and extends repeatedly).
Non-motor symptoms are usually called absence seizures. These can be typical or atypical absence seizures (staring spells). Absence seizures can also have brief twitches (myoclonus) that can affect a specific part of the body, or just the eyelids.
For focal onset seizures:
Motor symptoms may also include jerking (clonic), muscles becoming limp or weak (atonic), tense or rigid muscles (tonic), brief muscle twitching (myoclonus), or epileptic spasms. There may also be automatisms or repeated automatic movements, like clapping or rubbing of hands, lip smacking or chewing, or running.
Non-motor symptoms may include changes in sensation, emotions, thinking or cognition, autonomic functions (such as gastrointestinal sensations, waves of heat or cold, goosebumps, heart racing, etc.), or lack of movement (called behavior arrest).
For unknown onset seizures:
Motor seizures are described as either tonic-clonic or epileptic spasms. Non-motor seizures usually include a behavior arrest. This means that movement stops — the person may just stare and not make any other movements.
The overall goal of epilepsy treatments is no seizures and no side effects. Should patients not achieve these results with their existing therapies, alternative therapies might be explored to help with seizure reduction and management. In addition, the development of new therapies and treatment methods are continuously being studied for their ability to offer more people this goal.
Seizure medicines are the mainstay of epilepsy treatment, but they only work satisfactorily in about 2 of 3 people with epilepsy.5,6
Panayiotopoulos CP. A clinical guide to epileptic syndromes and their treatment. Second edition. London:Springer; 2007
Commission on Classification and Terminology of the International League Against Epilepsy 1989. https://www.ncbi.nlm.nih.gov/pubmed/2502382
Scheffer et al 2017. https://www.ncbi.nlm.nih.gov/pubmed/28276062
Fisher et al. 2017. https://www.ncbi.nlm.nih.gov/pubmed/28276060
Laxer KD, Trinka E, Hirsch LJ, et al. The consequences of refractory epilepsy and its treatment. Epilepsy Behav. 2014 Aug;37:59-70.
French JA. Refractory epilepsy: clinical overview. Epilepsia. 2007;48 Suppl 1:3-7.