Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. An epileptic seizure is the clinical manifestation of an abnormal, excessive, purposeless and synchronized electrical discharge in the brain cells called neurons. The occurrence of two or more unprovoked seizures defines epilepsy. The occurrence of just one seizure may warrant the definition in a more clinical usage where recurrence may be able to be prejudged. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical activity in the brain. These episodes can result in physical injuries, either directly such as broken bones or through causing accidents. In epilepsy, seizures tend to recur and may have no immediate underlying cause. Isolated seizures that are provoked by a specific cause such as poisoning are not deemed to represent epilepsy. People with epilepsy may be treated differently in various areas of the world and experience varying degrees of social stigma due to the alarming nature of their symptoms.
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with loss of consciousness, to shaking movements involving only part of the body with variable levels of consciousness, to a subtle momentary loss of awareness. Most of the time these episodes last less than two minutes and it takes some time to return to normal. Loss of bladder control may occur.
Lamotrigine, sold under the brand name Lamictal among others, is a medication used to treat epilepsy and stabilize mood in bipolar disorder. For epilepsy, this includes focal seizures, tonic-clonic seizures, and seizures in Lennox-Gastaut syndrome. In bipolar disorder, lamotrigine has not been shown to reliably treat acute depression; but for patients with bipolar disorder who are not currently symptomatic, it appears to be effective in reducing the risk of future episodes of depression.
Absence seizures are one of several kinds of generalized seizures. These seizures are sometimes referred to as petit mal seizures. Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy. Absence seizures are most common in children. They affect both sides of the brain.
Myoclonus is a brief, involuntary, irregular twitching of a muscle, a joint, or a group of muscles, different from clonus, which is rhythmic or regular. Myoclonus describes a medical sign and, generally, is not a diagnosis of a disease. These myoclonic twitches, jerks, or seizures are usually caused by sudden muscle contractions or brief lapses of contraction. The most common circumstance under which they occur is while falling asleep. Myoclonic jerks occur in healthy people and are experienced occasionally by everyone. However, when they appear with more persistence and become more widespread they can be a sign of various neurological disorders. Hiccups are a kind of myoclonic jerk specifically affecting the diaphragm. When a spasm is caused by another person it is known as a provoked spasm. Shuddering attacks in babies fall in this category.
Lennox–Gastaut syndrome (LGS) is a complex, rare, and severe childhood-onset epilepsy. It is characterized by multiple and concurrent seizure types, cognitive dysfunction, and slow spike waves on electroencephalogram (EEG). Typically, it presents in children aged 3–5 years and can persist into adulthood. It has been associated with several gene mutations, perinatal injuries, congenital infections, brain tumors/malformations, and genetic disorders such as tuberous sclerosis and West syndrome. The prognosis for LGS is poor with a 5% mortality in childhood and persistent seizures into adulthood (80–90%).
Stiripentol, sold under the brand name Diacomit, is an anticonvulsant medication used for the treatment of Dravet syndrome - a serious genetic brain disorder.
Reflex seizures are epileptic seizures that are consistently induced by a specific stimulus or trigger making them distinct from other epileptic seizures, which are usually unprovoked. Reflex seizures are otherwise similar to unprovoked seizures and may be focal, generalized, myoclonic, or absence seizures. Epilepsy syndromes characterized by repeated reflex seizures are known as reflex epilepsies. Photosensitive seizures are often myoclonic, absence, or focal seizures in the occipital lobe, while musicogenic seizures are associated with focal seizures in the temporal lobe.
Myoclonic epilepsy refers to a family of epilepsies that present with myoclonus. When myoclonic jerks are occasionally associated with abnormal brain wave activity, it can be categorized as myoclonic seizure. If the abnormal brain wave activity is persistent and results from ongoing seizures, then a diagnosis of myoclonic epilepsy may be considered.
Seizure types most commonly follow the classification proposed by the International League Against Epilepsy (ILAE) in 1981. These classifications have been updated in 2017. Distinguishing between seizure types is important since different types of seizure may have different causes, outcomes and treatments.
Dravet syndrome, previously known as severe myoclonic epilepsy of infancy (SMEI), is an autosomal dominant genetic disorder which causes a catastrophic form of epilepsy, with prolonged seizures that are often triggered by hot temperatures or fever. It is very difficult to treat with anticonvulsant medications. It often begins before 1 year of age, with 6 months being the age that seizures, characterized by prolonged convulsions and triggered by fever, usually begin.
Idiopathic generalized epilepsy (IGE) is a group of epileptic disorders that are believed to have a strong underlying genetic basis. Patients with an IGE subtype are typically otherwise normal and have no structural brain abnormalities. People also often have a family history of epilepsy and seem to have a genetically predisposed risk of seizures. IGE tends to manifest itself between early childhood and adolescence although it can be eventually diagnosed later. The genetic cause of some IGE types is known, though inheritance does not always follow a simple monogenic mechanism.
Juvenile myoclonic epilepsy (JME), also known as Janz syndrome, is a form of genetic generalized epilepsy, representing 5–10% of all epilepsy cases. Typically it first presents between the ages of 12 and 18 with myoclonic seizures. These events typically occur after awakening from sleep, during the evening or when sleep deprived. JME is also characterized by generalized tonic–clonic seizures, and a minority of patients have absence seizures. The genetics of JME are complex and rapidly evolving as over 20 chromosomal loci and multiple genes have been identified. Given the genetic and clinical heterogeneity of JME some authors have suggested that it should be thought of as a spectrum disorder.
Progressive Myoclonic Epilepsies (PME) are a rare group of inherited neurodegenerative diseases characterized by myoclonus, resistance to treatment, and neurological deterioration. The cause of PME depends largely on the type of PME. Most PMEs are caused by autosomal dominant or recessive and mitochondrial mutations. The location of the mutation also affects the inheritance and treatment of PME. Diagnosing PME is difficult due to their genetic heterogeneity and the lack of a genetic mutation identified in some patients. The prognosis depends largely on the worsening symptoms and failure to respond to treatment. There is no current cure for PME and treatment focuses on managing myoclonus and seizures through antiepileptic medication (AED).
Panayiotopoulos syndrome is a common idiopathic childhood-related seizure disorder that occurs exclusively in otherwise normal children and manifests mainly with autonomic epileptic seizures and autonomic status epilepticus. An expert consensus has defined Panayiotopoulos syndrome as "a benign age-related focal seizure disorder occurring in early and mid-childhood. It is characterized by seizures, often prolonged, with predominantly autonomic symptoms, and by an EEG [electroencephalogram] that shows shifting and/or multiple foci, often with occipital predominance."
Myoclonic astatic epilepsy (MAE), also known as myoclonic atonic epilepsy or Doose syndrome, is a generalized idiopathic epilepsy. It is characterized by the development of myoclonic seizures and/or myoclonic astatic seizures. Some of the common monogenic causes include mutations in the genes SLC6A1 (3p25.3),CHD2 (15q26.1), AP2M1 (10q23.2).
Jeavons syndrome is a type of epilepsy. It is one of the most distinctive reflex syndromes of idiopathic generalized epilepsy characterized by the triad of eyelid myoclonia with and without absences, eye-closure-induced seizures, EEG paroxysms, or both, and photosensitivity. Eyelid myoclonia with or without absences is a form of epileptic seizure manifesting with myoclonic jerks of the eyelids with or without a brief absence. These are mainly precipitated by closing of the eyes and lights. Eyelid myoclonia is the defining seizure type of Jeavons syndrome.
Early myoclonic encephalopathy (EME) is a rare neonatal-onset epilepsy developmental and epileptic encephalopathy (DEE) with an onset at neonatal period or during the first 3 months of life. It is marked by the presence of myoclonic seizures but multiple seizure types may occur. The electroencephalographic recording is abnormal with eitherusually a suppression-burst pattern or other significantly abnormal patterns. On most occasions the seizures are drug-resistant. After several months, the seizure pattern may develop into infantile spasms syndrome. The neurological exam is abnormal with a significant risk of early death. Various genetic and metabolic disorders are responsible. At present, EME and Ohtahara syndrome are recorded as distinct patterns in the categorization of epilepsies but both neonatal-onset epilepsy syndromes are considered to be merged in one unique entity. It is a severe type of epilepsy syndrome associated with high level of resistance to treatment and a high risk for cognitive impairment. The myoclonic seizures could be seen in other epilepsy syndromes. Multiple types of childhood epilepsies are usually mentioned as myoclonic epilepsies when the myoclonic seizures are a predominant feature.
People with epilepsy may be classified into different syndromes based on specific clinical features. These features include the age at which seizures begin, the seizure types, and EEG findings, among others. Identifying an epilepsy syndrome is useful as it helps determine the underlying causes as well as deciding what anti-seizure medication should be tried. Epilepsy syndromes are more commonly diagnosed in infants and children. Some examples of epilepsy syndromes include benign rolandic epilepsy, childhood absence epilepsy and juvenile myoclonic epilepsy. Severe syndromes with diffuse brain dysfunction caused, at least partly, by some aspect of epilepsy, are also referred to as epileptic encephalopathies. These are associated with frequent seizures that are resistant to treatment and severe cognitive dysfunction, for instance Lennox-Gastaut syndrome and West syndrome.
Occipital epilepsy is a neurological disorder that arises from excessive neural activity in the occipital lobe of the brain that may or may not be symptomatic. Occipital lobe epilepsy is fairly rare, and may sometimes be misdiagnosed as migraine when symptomatic. Epileptic seizures are the result of synchronized neural activity that is excessive, and may stem from a failure of inhibitory neurons to regulate properly.
