Lennox-Gastaut Syndrome

What is Lennox-Gastaut Syndrome?

Lennox-Gastaut syndrome is an uncommon form of epilepsy and is estimated to affect 1 and 5 percent of children who have epilepsy. Most cases develop between the ages of 3 and 5 years old. Although uncommon, Lennox-Gastaut is the most common form of intractable epilepsy. This means that it is difficult to manage.

What are the symptoms of Lennox-Gastaut syndrome?

Symptoms can vary from one individual to another and various types of seizure can occur.

Atonic seizures (also known as drop attacks): this is the most common type of seizure and is characterised by suddenly falling to the floor. These seizures can happen at any time and often result in injuries.

Absence seizures: absence seizures are fairly common in children with Lennox-Gastaut syndrome. They can last seconds or minutes and are characterised by the child appearing absent or vacant for the duration of the seizure. Sometimes, additional signs, such as fluttering eyes and nodding the head, may also occur. In some cases, absence seizures can be so frequent that they lead to a state known as non-convulsive status epilepticus, which causes prolonged episodes of the child appearing to be vacant. They may also feel floppy, their speech may be affected and they may dribble.

Tonic seizures: tonic seizures can happen at any time of day and cause stiffness in the arms and legs. It is also possible for Lennox-Gastaut syndrome to cause partial motor seizures, tonic-clonic seizures, myoclonic seizures and complex partial seizures.

How is Lennox-Gastaut syndrome diagnosed?

A test known as an EEG (electroencephalogram) is often the most useful diagnostic tool. This test highlights abnormalities even when a child is not having a seizure.

In some cases a clear cause, such as brain damage, meningitis or tuberous sclerosis (a condition that causes abnormal brain development), may be identified.

Often (in around half of cases), no clear cause can be found.

How is Lennox-Gastaut syndrome treated?

Lennox-Gastaut syndrome is difficult to treat and there are several medications may be trialled. These are:

• Lamotrigine
• Clobazam
• Sodium Valproate
• topiramate
• Phenytoin

In cases where seizures are frequent and very hard to bring under control, steroid medication may be recommended. Surgery may be beneficial for children who experience sudden drop attacks on a regular basis. Examples of procedures that could be carried out include corpus callosotomy and vagus nerve stimulation.

Sometimes, a ketogenic diet may be recommended. This diet is high in fat and low in carbohydrates.

What is the prognosis?

The prognosis is poor in terms of the ability to control seizures and very few children grow out of their seizures. Most experience regular seizures well into their adult life and will require long-term treatment and support. Although this condition does not affect life expectancy, it can increase the risk of complications that can shorten life expectancy, such as increased susceptibility to chest infections.