Epilepsy Syndromes

There are over 40 different types of epilepsy, including: Absence seizures, atonic seizures, benign Rolandic epilepsy, childhood absence, clonic seizures, complex partial seizures, frontal lobe epilepsy, Febrile seizures, Infantile spasms, Juvenile Myoclonic Epilepsy, Juvenile Absence Epilepsy, lennox-gastaut syndrom, Landau-Kleffner Syndrome , myoclonic seizures, Mitochondrial Disorders, Progressive Myoclonic Epilepsies, Psychogenic Seizures , Reflex Epilepsy, Rasmussen's Syndrome, Simple Partial seizures, Secondarily Generalized Seizures, Temporal Lobe Epilepsy, Toni-clonic seizures, Tonic seizures, Psychomotor Seizures, Limbic Epilepsy, Partial-Onset Seizures, generalised-onset seizures, Status Epilepticus, Abdominal Epilepsy, Akinetic Seizures, Auto-nomic seizures, Massive Bilateral Myoclonus, Catamenial Epilepsy, Drop seizures, Emotional seizures, Focal seizures, Gelastic seizures, Jacksonian March, Lafora Disease, Motor seizures, Multifocal seizures, Neonatal seizures, Nocturnal seizures, Photosensitive seizure, Pseudo seizures, Sensory seizures, Subtle seizures, Sylvan Seizures, Withdrawal seizures, Visual Reflex Seizures amongst others.

Each type of epilepsy presents with its own unique combination of seizure type, typical age of onset, EEG findings, treatment, and prognosis. The most widespread classification of the epilepsies . These genes encode various nicotinic acetylcholine receptors.

Benign centrotemporal lobe epilepsy of childhood or Benign rolandic epilepsy is an idiopathic localization-related epilepsy that occurs in children between the ages of 3 and 13 years with peak onset in prepubertal late childhood. Apart from their seizure disorder, these patients are otherwise normal. This syndrome features simple partial seizures that involve facial muscles and frequently cause drooling. Although most episodes are brief, seizures sometimes spread and generalize. Seizures are typically nocturnal and confined to sleep. The EEG may demonstrate spike discharges that occur over the centrotemporal scalp over the central sulcus of the brain (the Rolandic sulcus) that are predisposed to occur during drowsiness or light sleep. Seizures cease near puberty. Seizures may require anticonvulsant treatment, but sometimes are infrequent enough to allow physicians to defer treatment.

Benign occipital epilepsy of childhood (BOEC) is an idiopathic localization-related epilepsy and consists of an evolving group of syndromes. Most authorities include two subtypes, an early subtype with onset between 3–5 years and an late onset between 7–10 years. Seizures in BOEC usually feature visual symptoms such as scotoma or fortifications (brightly colored spots or lines) or amaurosis (blindness or impairment of vision). Convulsions involving one half the body, hemiconvulsions, or forced eye deviation or head turning are common. Younger patients typically experience symptoms similar to migraine with nausea and headache, and older patients typically complain of more visual symptoms. The EEG in BOEC shows spikes recorded from the occipital (back of head) regions. The EEG and genetic pattern suggest an autosomal dominant transmission as described by Ruben Kuzniecky et al. Lately, a group of epilepsies termed Panayiotopoulos syndrome that share some clinical features of BOEC but have a wider variety of EEG findings are classified by some as BOEC.

Catamenial epilepsy (CE) is when seizures typically occur around a woman's menstrual cycle.

Childhood absence epilepsy (CAE) is an idiopathic generalized epilepsy that affects children between the ages of 4 and 12 years of age, although peak onset is around 5–6 years old. These patients have recurrent absence seizures, brief episodes of unresponsive staring, sometimes with minor motor features such as eye blinking or subtle chewing. The EEG finding in CAE is generalized 3 Hz spike and wave discharges. Some go on to develop generalized tonic-clonic seizures. This condition carries a good prognosis because children do not usually show cognitive decline or neurological deficits, and the seizures in the majority cease spontaneously with onging maturation.

Dravet's syndrome Severe myoclonic epilepsy of infancy (SMEI). This generalized epilepsy syndrome is distinguished from benign myoclonic epilepsy by its severity and must be differentiated from the Lennox-Gastaut syndrome and Doose’s myoclonic-astatic epilepsy. Onset is in the first year of life and symptoms peak at about 5 months of age with febrile hemiclonic or generalized status epilepticus. Boys are twice as often affected as girls. Prognosis is poor. Most cases are sporadic. Family history of epilepsy and febrile convulsions is present in around 25 percent of the cases.

Frontal lobe epilepsy, usually a symptomatic or cryptogenic localization-related epilepsy, arises from lesions causing seizures that occur in the frontal lobes of the brain. These epilepsies can be difficult to diagnose because the symptoms of seizures can easily be confused with nonepileptic spells and, because of limitations of the EEG, be difficult to "see" with standard scalp EEG.

Juvenile absence epilepsy is an idiopathic generalized epilepsy with later onset that CAE, typically in prepubertal adolescence, with the most frequent seizure type being absence seizures. Generalized tonic-clonic seizures can occur. 3 Hz spike-wave or multiple spike discharges can be seen on EEG. Prognosis is mixed, with some patients going on to a syndrome that is poorly distinguishable from JME.

Juvenile myoclonic epilepsy (JME) is an idiopathic generalized epilepsy that occurs in patients aged 8 to 20 years. Patients have normal cognition and are otherwise neurologically intact. The most common seizures are myoclonic jerks, although generalized tonic-clonic seizures and absence seizures may occur as well. Myoclonic jerks usually cluster in the early morning after awakening. The EEG reveals generalized 4–6 Hz spike wave discharges or multiple spike discharges. Interestingly, these patients are often first diagnosed when they have their first generalized tonic-clonic seizure later in life when they experience sleep deprivation (e.g., freshman year in college after staying up late to study for exams). Alcohol withdrawal can also be a major contributing factor in breakthrough seizures as well. The risk of the tendency to have seizures is lifelong; however, the majority have well-controlled seizures with anticonvulsant medication and avoidance of seizure precipitants.

Lennox-Gastaut syndrome (LGS) is a generalized epilepsy that consists of a triad of developmental delay or childhood dementia, mixed generalized seizures, and EEG demonstrating a pattern of approximately 2 Hz "slow" spike-wave. Onset occurs between 2–18 years. As in West syndrome, LGS result from idiopathic, symptomatic, or cryptogenic causes, and many patients first have West syndrome. Authorities emphasize different seizure types as important in LGS, but most have astatic seizures (drop attacks), tonic seizures, tonic-clonic seizures, atypical absence seizures, and sometimes, complex partial seizures. Anticonvulsants are usually only partially successful in treatment.

Ohtahara Syndrome is a rare but severe form of epilepsy syndrome combined with cerebral palsy and characterised with frequent seizures which typically start in the first few days of life. Sufferers trend to be severely disabled and their lives short (they are unlikely to reach adulthood).

Primary reading epilepsy is a reflex epilepsy classified as an idiopathic localization-related epilepsy. Reading in susceptible individuals triggers characteristic seizures.

Progressive myoclonic epilepsies define a group of symptomatic generalized epilepsies characterized by progressive dementia and myoclonic seizures. Tonic-clonic seizures may occur as well. Diseases usually classified in this group are Unverricht-Lundborg disease, myoclonus epilepsy with ragged red fibers , Lafora disease, neuronal ceroid lipofucinosis, and sialdosis.

Rasmussen's encephalitis is a symptomatic localization-related epilepsy that is a progressive, inflammatory lesion affecting children with onset before the age of 10. Seizures start as separate simple partial or complex partial seizures and may progress to epilepsia partialis continuata (simple partial status epilepticus). Neuroimaging shows inflammatory encephalitis on one side of the brain that may spread if not treated. Dementia and hemiparesis are other problems. The cause is hypothesized to involve an immulogical attack against glutamate receptors, a common neurotransmitter in the brain.

Symptomatic localization-related epilepsies Symptomatic localization-related epilepsies are divided by the location in the brain of the epileptic lesion, since the symptoms of the seizures are more closely tied to the brain location rather than the cause of the lesion. Tumors, atriovenous malformations, cavernous malformations, trauma, and cerebral infarcts can all be causes of epileptic foci in different brain regions.

Temporal lobe epilepsy (TLE), a symptomatic localization-related epilepsy, is the most common epilepsy of adults who experience seizures poorly controlled with anticonvulsant medications. In most cases, the epileptogenic region is found in the midline (mesial) temporal structures (e.g., the hippocampus, amygdala, and parahippocampal gyrus). Seizures begin in late childhood and adolescence. Most of these patients have complex partial seizures sometimes preceded by an aura, and some TLE patients also suffer from secondary generalized tonic-clonic seizures. If the patient does not respond sufficiently to medical treatment, epilepsy surgery may be considered.

West syndrome is a triad of developmental delay, seizures termed infantile spasms, and EEG demonstrating a pattern termed hypsarrhythmia. Onset occurs between 3 months and 2 years, with peak onset between 8–9 months. West syndrome may arise from idiopathic, symptomatic, or cryptogenic causes. The most common cause is tuberous sclerosis. The prognosis varies with the underlying cause. In general most surviving patients remain with significant cognitive impairment and continuing seizures and may evolve to another eponymic syndrome, Lennox-Gastaut syndrome.

Epilepsy Syndromes

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