What is Lennox Gastaut Syndrome?
Lennox-Gastaut syndrome (LGS) is a rare but severe form of epilepsy that primarily affects children. The condition was first described by doctors in France and the United States in the 1960s. The syndrome is named after these two doctors. This condition causes several kinds of seizures, changes in brain wave patterns, which are tracked through an Electroencephalogram (EEG)- a test used to evaluate the electrical activity in the brain, and can impair a child’s intellectual abilities. LGS is considered to be one of the ‘epileptic encephalopathies’, which is a term used to describe types of epilepsy that interrupt the normal functioning of the brain.
What Causes Lennox Gastaut Syndrome?
Lennox-Gastaut syndrome (LGS) is a condition that can happen for all kinds of reasons. In fact, around 25% of people with LGS have no obvious cause. This condition can be broken down into two main types:
The first type is called Secondary or Symptomatic LGS, which accounts for about 75% of all cases. Here we can identify a specific cause, usually related to widespread damage in the brain. Some potential causes include a disorder called tuberous sclerosis, various infections or inflammations like encephalitis and meningitis, injuries to the front part of the brain, trauma from birth, metabolic disorders, and malformations in brain development. Although West syndrome (also named infantile spasms) isn’t a specific cause of LGS, it’s important to note that around 30% of children who develop LGS previously had West syndrome. These children usually have more serious symptoms. It’s also generally observed that the outlook tends to be worse for Secondary LGS.
The second type is known as Idiopathic or Cryptogenic LGS, where no specific cause can be identified. This type tends to show up later in life compared to Secondary LGS. Recent research in genetics have identified new mutations, or changes, in certain genes including SCN1A, GABRB3, ALG13, and CHD2. However, at this time, we aren’t completely sure how much these gene mutations contribute to the development of LGS.
Risk Factors and Frequency for Lennox Gastaut Syndrome
Lennox-Gastaut syndrome (LGS) is a type of epilepsy that mainly affects children. It makes up roughly 2-5% of childhood epilepsy cases and around 10% of cases in kids under 5 years old. Although it’s not a common condition, affecting only around 0.1 to 0.28 people out of 100,000 within the general population, and 2 out of 100,000 children, it’s prevalence is about 26 in every 100,000 people. LGS is more frequently diagnosed in males and is common in children with developmental and/or cognitive issues due to its link with brain injury. There’s no known difference in how often LGS occurs between different races.
- Lennox-Gastaut syndrome (LGS) represents 2-5% of all childhood epilepsy cases, and about 10% of cases in children under 5.
- In the general population, LGS incidence is between 0.1 to 0.28 per 100,000 people.
- For children specifically, LGS incidence is estimated at 2 per 100,000.
- The overall prevalence of LGS is around 26 per 100,000 people.
- LGS is more common in males than in females.
- Children with developmental or cognitive issues are often diagnosed with LGS due to the syndrome’s link with brain injury.
- No racial differences in LGS occurrence have been reported.
Signs and Symptoms of Lennox Gastaut Syndrome
Lennox-Gastaut syndrome (LGS) is a medical condition characterized by three main symptoms: different types of seizures, a specific pattern on brain wave testing (EEG), and intellectual impairment. Here’s what you need to know about each symptom:
- Seizures: Children with LGS typically start having seizures between the ages of 1 and 7, peaking around age 3. They experience different types of seizures including tonic (body stiffness), atonic or drop attacks (sudden loss of muscle tone causing falls), atypical absence (brief, sudden lapses of consciousness), myoclonic (sudden muscle jerks), and generalized tonic-clonic (whole-body convulsions). Tonic seizures, especially the ones occurring at night, are a distinguishing feature of LGS. Atypical absence seizures are also common in LGS, where the child may have more than just staring episodes associated with eye blinking. Atonic seizures, which result in falls due to loss of muscle control, are seen in over half of LGS patients and are kept in focus during treatment due to the risks from frequent falls. Some LGS patients may also experience non-convulsive status epilepticus, a state of ongoing seizure activity resulting in symptoms like dizziness, staring, apathy, stupor, and unresponsiveness. Identifying the types of seizures becomes challenging due to multiple, daily seizure episodes. In such cases, continuous EEG monitoring can help.
- EEG pattern: Also required for diagnosing LGS is an identified characteristic pattern in the EEG results. Consult the “Evaluation” section for more details.
- Intellectual Impairment: Although the early growth of a child with LGS may be normal, a decline is noticed after the seizures start causing issues such as developmental delay, intellectual impairment, decreased learning abilities, and behavioral problems. This decline worsens with age. A good number of patients lost learned skills (psychomotor regression), displaying behavioral issues like irritability, hyperactivity, and sometimes even psychosis. Up to 20% of patients can have normal memory and cognition, but their information processing speed is slower. As a result, many patients end up with cognitive disabilities.
Testing for Lennox Gastaut Syndrome
Lennox-Gastaut syndrome (LGS), a serious form of epilepsy, is identified through a combination of your medical history and specific electrical patterns in your brain recorded through an Electroencephalogram (EEG). This electrical test can detect unusual brain activity related to seizures.
Establishing an LGS diagnosis involves an examination of your birth history, current and past health issues, including the nature and onset of your seizures. Also, your doctor may measure your motor skills and run laboratory tests such as blood work, urinalysis, urine drug testing, and tests to check for any metabolic abnormalities.
To get a more complete picture, your doctor might conduct an MRI of your brain. This imaging technique produces detailed images of your brain and can help determine if there are any structural abnormalities causing your seizures.
Your doctor might also conduct an EEG while you’re awake and asleep, and in some cases, an EEG with video may be used to better understand and diagnose your seizures.
From EEG, your doctor will look for specific patterns characteristic to LGS. Typically, these patterns involve slowed brain activity interrupted by bursts of rapid activity. These patterns, called spike and wave discharges, often show up more in the frontal area of the brain, which impacts cognitive functions. Some of these patterns only become apparent during sleep, which makes sleep EEGs particularly important.
As the symptoms and EEG results for LGS can change over time, making an initial diagnosis can be challenging, especially if no cause for the condition is found (also known as idiopathic or cryptogenic LGS). Regular check-ups and follow-up EEGs are often necessary to confirm the diagnosis.
Treatment Options for Lennox Gastaut Syndrome
Lennox-Gastaut syndrome (LGS) is a type of epilepsy, and its treatment primarily focuses on controlling seizures in order to improve the patient’s brain function, mood, and overall quality of life. The treatment includes medication, changes in diet, and sometimes, surgery.
In terms of medication, the goal is to reduce seizures, but it often proves challenging because different types of seizures may need different medications, and some drugs might worsen certain types of seizures. Medications approved for managing LGS include felbamate, lamotrigine, rufinamide, valproate, benzodiazepines, topiramate, and a drug derived from cannabis called cannabidiol. These drugs help control seizures and may improve mood, behavior, and speech.
Unfortunately, not all epilepsy medications help LGS. Some drugs such as phenytoin, carbamazepine, oxcarbazepine, gabapentin, lacosamide, and phenobarbital can actually make some seizure types worse and are therefore avoided. There are some reports that corticosteroids and a treatment called intravenous immunoglobulin (IVIG) can reduce seizure frequency, but these have not undergone detailed clinical trials.
If medication proves insufficient to manage seizures, doctors may recommend dietary changes. Certain diets, such as the ketogenic diet, the modified Atkins diet, and the low-glycemic-index diet, have been shown to decrease seizures and potentially reduce the doses of medication needed.
When medication and dietary changes don’t sufficiently control seizures, surgery could be the next step. One type of surgery is called vagus nerve stimulation (VNS), usually combined with medication, and is particularly effective for treating drop attacks and tonic-clonic seizures, the types of seizures commonly seen in LGS. VNS can improve over time and may also help improve mood and behavior.
Other surgical options include operations to remove a part of the brain (resection), disconnecting the two parts of the brain (corpus callosotomy), or removing one half of the brain (hemispherectomy). Before, people with LGS were thought to be ineligible for surgery, but it is now known that those with a localized area in their brain causing the seizures (like tubers, tumors, malformations) can be considered for resection.
What else can Lennox Gastaut Syndrome be?
Lennox-Gastaut syndrome (LGS) is a condition that changes over time, making it hard to diagnose quickly. It often takes many years of monitoring to confirm. There are other conditions that may appear similar to LGS, including:
- Dravet syndrome
- Myoclonic-atonic epilepsy (also known as Doose syndrome)
- Atypical benign focal epilepsy of childhood
- Pseudo-Lennox syndrome
- West syndrome
What to expect with Lennox Gastaut Syndrome
Overall, patients with a condition called Lennox-Gastaut syndrome (LGS), a type of severe epilepsy that starts in childhood, tend to have serious outcomes. The death rate lies between 3% and 7% when looked at over a period of 8 to 10 years. Often, death can occur due to accidents.
If a patient has had a history of infantile spasms or another type of epilepsy called West syndrome, they generally have a harder time controlling the seizures and may also have more serious cognitive problems (problems with thinking and understanding).
On the other hand, patients with a variety of LGS not linked to other conditions (idiopathic LGS) generally experience less extreme symptoms and less impairment.
There is also a risk of something called SUDEP, or Sudden Unexpected Death in Epilepsy, which might be more common in LGS patients. This is because these patients often struggle to control their seizures.
Preventing Lennox Gastaut Syndrome
Living with Lennox-Gastaut syndrome (LGS) – a condition that causes frequent seizures and intellectual challenges – can require a lot of support and effort from the patient’s family, whether the patient is a child or an adult. Because LGS often needs round-the-clock care, it’s important to have a dedicated care team that could include a children’s doctor (pediatrician), a brain specialist (neurologist), a mental health exert (psychiatrist), a psychologist who specializes in brain behavior (neuropsychologist), and a surgeon.
In most cases, patients and their families can also greatly benefit from social services and rehabilitation assistance, such as physical therapy, job-related therapy (occupational), and speech therapy. These services are designed to support people with LGS so they can get help as early as possible, whether that’s in figuring out a diagnosis, beginning treatment, getting an education, or finding support services.
It’s also important for families to learn about resources like the LGS Foundation and the Epilepsy Foundation of America. These organizations can provide valuable information to improve the lives of people with LGS and their families.
