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Lennox-Gastaut Syndrome

What is Lennox-Gastaut Syndrome?

Lennox-Gastaut Syndrome (LGS) is a rare and severe form of epilepsy that typically begins in childhood. It is characterized by multiple types of seizures, developmental delays, and cognitive impairment. LGS is often challenging to treat, and individuals with this syndrome may experience a poor quality of life due to the frequency and severity of their seizures.

Some key features of Lennox-Gastaut Syndrome include:

1. Multiple Seizure Types: Individuals with LGS experience several different types of seizures, including tonic seizures (muscle stiffening), atonic seizures (loss of muscle tone, leading to falls), atypical absence seizures (staring spells with subtle body movements), and myoclonic seizures (sudden jerking movements). These seizures can be frequent and difficult to control. Seizures begin in childhood but different types may emerge over time. Focal (one area of the brain) seizures become more common in teens and adults.

Below shows the development and seizure progression of a 2 1/2 year old diagnosed with LGS.

2. Cognitive and Developmental Impairment: LGS often leads to significant cognitive and developmental delays. Children with LGS may experience intellectual disability, behavioral problems, and difficulties with speech and language development. According to the Epilepsy Foundation prior to seizure onset, 70-80% (or 7 to 8 out of 10) of children have a history of delayed development and neurological problems. When seizures begin, these problems are almost always seen and often get worse over time.

3. Seizure Onset: LGS typically begins in early childhood, usually between the ages of 3 and 5, although it can start later. It may develop in children who had previously been diagnosed with other forms of epilepsy. In many cases, Lennox-Gastaut syndrome develops after another type of epilepsy, such as West syndrome (infantile spasms), Ohtahara syndrome or Epilepsy in Infancy with Migrating Focal Seizures.

A run of generalized spike and waves

EEG showing a seizure onset, notation of patient's clinical correlated movements of head drop and arms extended.

4. EEG Patterns: The electroencephalogram (EEG) of individuals with LGS often shows a characteristic pattern known as "slow spike-wave complexes," which is a key diagnostic feature.

5. Difficult to Treat: LGS can be challenging to treat, and many individuals with this syndrome do not respond well to traditional antiepileptic medications. Seizures often persist despite treatment efforts. Most seizures in LGS don’t respond well to usual seizure medicines, and side effects can be hard to tolerate. Partial relief from seizures may be found with medications. Dietary treatments can often reduce the number of seizures in people with LGS. The number or doses of some seizure medications may be lowered if diet therapy works well. Rarely, people with Lennox-Gastaut syndrome will be found to have a focal area of brain that can be removed to help control seizures.

6. Comorbidities: In addition to seizures and cognitive impairment, individuals with LGS may also have other comorbidities, such as behavioral and psychiatric issues, sleep disturbances, and a higher risk of injuries due to falls during seizures. Those with LGS have an increased risk of early death including Sudden Unexpected Death in Epilepsy (SUDEP) .

Management of LGS typically involves a combination of medications, including anti-seizure drugs, and may also include dietary therapies (such as the ketogenic diet) and surgical options in some cases. While it can be a very challenging condition to manage, early intervention and a comprehensive treatment approach can help improve the quality of life for individuals with Lennox-Gastaut Syndrome. It is important for individuals with LGS to work closely with healthcare professionals, including neurologists and epileptologists, to develop a personalized treatment plan.

What causes LGS?

The exact cause of LGS is often unknown, but it is believed to be related to a combination of genetic, neurological, and developmental factors. Some potential causes and contributing factors include:

Brain abnormalities: Many individuals with LGS have structural abnormalities or lesions in the brain. These can result from various factors, including brain injuries, infections, or developmental abnormalities that occur during fetal development.

Genetic factors: Some cases of LGS may be linked to specific genetic mutations or abnormalities. Researchers have identified certain genes that may play a role in the development of LGS, but it is often a complex genetic interplay.

Developmental delays: Children with developmental delays or intellectual disabilities may be at a higher risk of developing LGS. The condition can sometimes be a result of underlying developmental disorders.

Brain inflammation: In some cases, inflammation of the brain (encephalitis) or inflammation of the brain's blood vessels (vasculitis) may trigger or contribute to the development of LGS.

Infections: Certain infections, such as viral encephalitis, can lead to brain damage and increase the risk of LGS in some individuals.

Metabolic disorders: In rare cases, metabolic disorders that affect the body's ability to process nutrients and energy can lead to seizures and LGS.

It's important to note that LGS is a complex condition, and its exact cause can vary from one individual to another. In many cases, the cause remains unknown (idiopathic). Diagnosis and management of LGS typically involve a multidisciplinary approach, including neurologists, geneticists, and other specialists, to address the specific needs and underlying factors of each patient. Treatment options often include anti-seizure medications, dietary therapies, and, in some cases, surgical interventions to reduce seizure activity and improve the quality of life for individuals with LGS.


LGS Foundation

Epilepsy Foundation

International League Against Epilepsy

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