Lennox-Gastaut Syndrome

What is Lennox-Gastaut syndrome?
Lennox-Gastaut syndrome is a serious form of epilepsy that starts in early childhood. Children with Lennox-Gastaut syndrome have more than one type of seizure, including:

• Tonic seizures. This is when the body, arms and legs stiffen. The child loses consciousness. These usually are brief  lasting about 20 seconds.  These are common and frequently occur at night.
• Atonic seizures. In this type of seizure, the child suddenly loses muscle strength and often falls to the ground. The child loses consciousness, so they do not protect themselves and may be injured by the fall. These most often last less than 15 seconds.
• Atypical absence seizures. These seizures, which last from 5 to 30 seconds, consist of staring spells. The child may not respond or is not fully responsive.
• Myoclonic seizures. These involve the sudden jerking of muscles.  These seizures usually only last a second or two, but several may occur in within a short period of time.

Children with Lennox-Gastaut syndrome may have frequent seizures - up to 70 or more in a day. They may also experience brief, relatively seizure-free periods.

Most children with Lennox-Gastaut syndrome have some degree of impaired intellectual functioning, developmental delay and behavioral problems.

Any child who has a seizure should be evaluated by a doctor.

What is status epilepticus?
Status epilepticus is a term to describe a continuous state of seizure activity or a series of seizures without recovery between them. Children with Lennox-Gastaut syndrome most often have non-convulsive status epilepticus, which can be very difficult to recognize. During this they may stare off, twitch, or just be less responsive.

It is very important to recognize and treat status epilepticus. This can sometimes be difficult. Children experiencing status epilepticus may seem confused, cranky, off balance or tired. Children in status epilepticus need medical treatment to bring a stop to their seizures.

What causes Lennox-Gastaut syndrome?
The cause may not be known, but Lennox-Gastaut syndrome can sometimes be the result of:

• Brain infections including encephalitis, meningitis, toxoplasmosis and rubella
• Brain  injury, sometimes caused by a difficult birth
• Brain diseases such as tuberous sclerosis
• Metabolic disorders
• Rare childhood diseases
• Malformations of the brain

How is Lennox-Gastaut syndrome diagnosed?
Neurologists look for three primary signs when diagnosing Lennox-Gastaut syndrome:

• Multiple types of seizures that are difficult to control
• Developmental delay with behavior problems
• A specific EEG abnormality

The multi-disciplinary epilepsy team at Le Bonheur Children's Medical Center can perform an extensive evaluation to determine whether your child has Lennox-Gastaut syndrome.

What is the treatment for Lennox-Gastaut syndrome?
Lennox-Gastaut syndrome is difficult to treat, as children with this condition often don't respond well to seizure medications. A combination of treatments may be prescribed. In addition to medical therapy or study medication, other treatments are:

1. Some children are put on the ketogenic diet. This is a very strict medical diet that's high in fats and low in carbohydrates and protein.
2. Surgery may be recommended for children who don't respond to medication or the Ketogenic diet. The types of surgery performed for children with Lennox-Gastaut syndrome include:
   • Corpus callosotomy. The nerve fibers between the two sides of the brain are cut. This interrupts the spread of seizures from one side of the brain to the other.
   • Focal resection or Hemisperectomy
3. Vagus nerve stimulation. A small device, called a vagus nerve stimulator (VNS) is implanted beneath the skin of the chest.  A thin wire is placed around the vagus nerve in the neck and then connected to the device.  This device is programmed to send impulses on a regular basis every few seconds to minutes to the brain.  Additionally, if the child feels a seizure coming on, he/she may activate the device by holding a small magnet over the battery.  This sends an extra impulse to the brain and in many cases, this will help stop the seizure, or quicken the recovery.

What's the outlook?
The outlook varies greatly from one child to the next. Lennox-Gastaut syndrome usually continues into adulthood. Sometimes seizure control gets better as the child gets older, but usually there is a need for ongoing therapy.  The types of seizures experienced may also change.

Children whose seizures can be controlled may have intellectual and behavioral development that improves. Those who continue to have frequent seizures  may suffer from developmental delay.

Why Le Bonheur Children's?
The epilepsy team at Le Bonheur Children's Medical Center includes some of the most respected pediatric epilepsy specialists in the United States. The hospital's Comprehensive Epilepsy Program is a key component of the hospital's Neuroscience Institute, a center of excellence dedicated to the evaluation and treatment of neurological disorders in children and adolescents. Children from across the country visit Le Bonheur each year to be treated at the Institute.