Lennox-Gastaut syndrome is a type of childhood epilepsy that’s particularly severe. This condition causes multiple types of seizures that can lead to permanent brain damage. That damage often results in learning difficulties and other disabilities. Possible treatments include medication, implanted devices, ketogenic diet and brain surgery.
Lennox-Gastaut syndrome (LGS) is a type of severe epilepsy that appears during childhood. This condition is particularly serious and difficult to treat, and it usually has severe effects. However, there are several newer medications approved to treat this condition, and there are also possible nonmedication treatments.
Lennox-Gastaut syndrome is a condition that almost always starts before age 10, with a diagnosis most likely to happen between ages 3 and 5. It’s slightly more common in male children.
Lennox-Gastaut syndrome is rare, with an estimated 1 to 2 cases out of every 1 million people. This condition makes up about 1% to 2% of all epilepsy cases.
Epilepsy refers to a family of conditions that cause malfunctions in how brain cells send signals to each other. Lennox-Gastaut syndrome is a particularly severe type of epilepsy for the following reasons:
There are many different possible symptoms of LGS. Some of them are visible in everyday life or activities. Others are only visible during a seizure.
LGS usually causes learning and behavior problems, which start soon after seizures begin and often worsen over time as seizures continue. Those learning and cognitive problems are often permanent and last into adulthood.
Children with LGS usually struggle with learning, making friends and communicating with others. They may also have trouble controlling emotions. Many children will show signs similar to those seen in children with autism spectrum disorder.
Seizures usually happen in three stages:
LGS usually involves multiple seizure types. The most likely types of seizures and their effects are as follows:
While most of the seizures themselves are short, people with LGS commonly have "clusters" of seizures, which means several seizures in a short period. In more than two-thirds of cases, people with LGS will have “status epilepticus." That’s when one of two things happens:
Status epilepticus is a medical emergency. It’s especially dangerous because it can cause permanent brain damage and death.
Atypical absence seizures
Other symptoms and their seizure types
Lennox-Gastaut syndrome can happen for multiple reasons. Some of the causes happen before a person’s birth. Others happen because of events in early childhood. In about one-fourth of LGS cases, there’s no identifiable cause.
Examples of identified causes include:
Researchers have also identified “de novo” mutations that are more likely to happen in people with LGS. De novo (which means “from the beginning”) mutations are spontaneous errors in a person’s DNA. That means the mutation happened because of a DNA error in either the sperm or egg they developed from, but it wasn't an error from either parent’s DNA.
However, genetics may still play a role in whether or not a person develops this condition. As many as 30% of people with LGS have a family history of epilepsy. However, more research is necessary to show what role genetics play in this condition.
Lennox-Gastaut syndrome is not contagious, and one person can’t pass it to another. Some contagious infections can cause brain damage that leads to LGS, but these infections aren’t guaranteed causes.
Diagnosing LGS usually takes a combination of diagnostic testing and a healthcare provider doing a neurological exam. A pediatrician may suspect this condition based on parents’ reports of their child’s symptoms, especially if the child also has learning difficulties or problems with behavior.
The most common tests used to diagnose LGS include:
There are other possible tests that a person might also undergo to rule out similar conditions. A healthcare provider can explain more about other possible tests and answer any questions you might have about them.
There are several treatment options for LGS, but this condition has a reputation as being extremely difficult to treat. In many cases, treatment involves one or even a combination of the following:
Lennox-Gastaut syndrome commonly resists medication treatments, which is what makes this condition so difficult to manage. In many cases, multiple medications are necessary. A complicating factor is that some antiseizure medications that limit certain types of seizures may increase how often other kinds happen.
When this condition resists treatments, healthcare providers may try to focus the treatment options on preventing certain types of seizures or reducing how often they happen. Preventing atonic seizures, for example, is especially important because these create a danger of fall injuries.
For many people with severe epilepsy, diet changes can help limit the frequency of seizures or stop them entirely. The ketogenic diet for epilepsy, which focuses on high protein and fat intake while avoiding carbohydrates, is one that providers often recommend. This can be an option when medication treatments haven’t worked.
While the ketogenic diet is gaining a reputation in treating severe epilepsy, it does have a few drawbacks. This diet only works when followed closely. That’s because taking in too many carbohydrates (found in sugary and starchy foods) can cause a return of seizures. However, other similar diets also might help, and a healthcare provider can help you learn about and try one of the modified diets if you choose.
In some cases, especially when other treatment attempts don’t succeed, surgery may be the best option. Examples of these kinds of procedures include:
The complications of the treatments are specific to the treatments involved. Because of that, you should talk to a healthcare provider about the specific complications and side effects of the treatments that will affect you or your loved one. The provider can best tailor that information to your particular situation, including your circumstances, other conditions involved, and more.
The time it takes to recover after treatment depends very strongly on the treatments used and the overall situation. A healthcare provider is the best person to explain what to expect and the likely timeline for recovery.
In many cases, LGS is not a preventable condition, and it's not possible to reduce your risk of it happening. The exception is the prevention of head and brain injuries that can lead to LGS. Ensuring that your children use approved, certified helmets is the only way to avoid this condition happening because of injuries.
Lennox-Gastaut syndrome is a condition that usually has severe impacts. Most children with this condition will have learning difficulties and permanent brain damage that limits their mental abilities. Children with this also have a higher risk of injuries from falls because atonic seizures (drop attacks) are so common and lead to falls.
This condition is also difficult to treat. Most children with this condition need lifelong skilled medical care because they can’t care for themselves alone. However, some people with this condition only have minimal brain damage, which means they can live independently.
Unless treated in a way that stops seizures entirely, which is rare, LGS is a lifelong condition.
The biggest risks from Lennox-Gastaut syndrome come from damage to the brain due to uncontrolled seizures or falls that happen because of seizures. Because of those risks, people with LGS have a death rate between 3% and 7% over 10 years after their diagnosis.
In some cases, medical procedures can stop seizures from LGS. That stops this condition but cannot undo any brain damage from earlier seizures.
If you or a loved one has LGS, it’s important to follow your healthcare provider’s guidance on how to take care of yourself. That includes the following:
You or your child’s healthcare provider will recommend regular visits as needed. You should also see your healthcare provider if the seizure symptoms change in any way that's noticeable or affects your usual routine and activities.
You should go to the nearest hospital emergency room if you or your child has one or more seizures that meet the definition of status epilepticus, which is a medical emergency. That is when one or more seizures meets the following criteria:
A note from Cleveland Clinic
Lennox-Gastaut syndrome is a rare type of severe childhood epilepsy. It usually has severe impacts on a child’s life, many of which are permanent and last into adulthood. While this condition is difficult to treat, newer medications, procedures and treatment methods can help ease the severity of this condition and limit how it progresses. In uncommon cases, treatments can provide complete remission of this condition entirely. However, more research is necessary before this condition is truly treatable or curable.
Last reviewed by a Cleveland Clinic medical professional on 06/02/2022.
Learn more about our editorial process.