The disorder is named after two epileptologists who defined the syndrome. Lennox–Gastaut syndrome (LGS) is also called Lennox syndrome or childhood epileptic encephalopathy.
Epilepsy Syndromes
A syndrome is a condition in which a group of people share the same set of symptoms. There are numerous childhood epilepsy syndromes. Some of these are:
- West syndrome – infantile spasms which may progress into LGS.
- Benign Rolandic epilepsy – seizures in this syndrome begin between the ages of 2 and 13. The seizures are usually partial, occur at night, and often are outgrown by the mid-teens.
- Juvenile myoclonic epilepsy – this syndrome may begin in early childhood through the early teens. The main symptoms are muscle jerks and twitches (myoclonic seizures)which may progress into absence and tonic-clonic seizures.
Definitions of Lennox–Gastaut Syndrome
The definition of LGS is evolving. Multiple types of seizures that are resistant to treatment with anticonvulsants and a distinct EEG pattern(slow spike-and-wave pattern) are traits of LGS specialists generally agree upon. Some specialists include certain seizure types as criteria of LGS. Others stress cognitive impairment as a defining trait of LGS.
Symptoms
Symptoms of LGS usually develop between the first year of life and age 8. Children with LGS often have cognitive disabilites, brain damage, and poor psychomotor skills. Children may be normal at birth and develop mixed seizure types later as a result of illness or injury.
The seizures, especially drop attacks, may cause serious injuries. Children with LGS often need to wear helmets to protect themselves from injury when they have seizures. The types of seizures seen in LGS may include:
- Atonic (astatic) – also called drop attacks. During a seizure the body suddenly loses muscle tone, the child may simply collapse, the head drop, or the child’s hand may drop whatever it is holding.
- Atypical absence – this type seizure may look like daydreaming with staring spells, usually very short.
- Clonic – involuntary muscle contractions which can occur on both sides of the body occur with clonics. They may affect only one area such as the face or a single hand.
- Complex partial – seizure activity is limited to one part of the brain and affects consciousness.
- Generalized tonic clonic (GTC) – convulsive seizures which cause loss of consciousness.
- Myoclonic – very brief jerking and twitching of a group of muscles. These are milder than contractions seen in clonic seizures, but may also cause falling.
- Tonic – causes muscle contractions and rigidity without loss of consciousness and may affect both sides of the body.
Causes of Lennox–Gastaut
There is no single cause for the development of LGS. The syndrome is divided into types, symptomatic, those with a known cause, and idiopathic, cause unknown. About 70% of the time the disorder causing LGS can be identified. Some of the known causes of the seizure types and other symptoms seen in LGS are:
- Cortical dysplasia – malformations of the brain’s cortex
- Encephalitis – inflammation of the brain, may be caused by viral infection
- Meningitis – infection of the lining of the brain and spinal cord
- Tuberous sclerosis – an inherited disorder in which benign tumors develop in the brain, eyes, skin, and internal organs.
- Toxoplasmosis – parasitic infection of the brain (known as congenital toxoplasmosis when it is present at birth).
- Rubella – German measles
- Inborn errors of metabolism
Diagnosing LGS
Ring Chromosome 20 Foundation advises evaluating all children who develop refractory seizures for this inherited disorder.
EEG monitoring is used to identify the patterns of brain wave activity unique to LGS. Writing in Lennox-Gastaut Syndrome (Medscape Jun 15 2011), Tracy Glauser, MD, advises, “Record both waking and sleep EEG, to assist in confirming a suspected diagnosis and to capture and classify each of the patient’s multiple seizure types.”
MRI, CT, PET and SPECT scans may also be used to distinguish LGS from other conditions.
The symptoms of LGS, including various seizure types, may not be present when the syndrome is first suspected. A definite diagnosis may be put on hold to see if other symptoms develop over time. It is common for the symptoms of children with West Syndrome to evolve into those of LGS.
Treatment for Lennox–Gastaut
Drugs, surgery, and diets are all possible therapies for LGS. The syndrome is so complex, it is uncommon for any treatments to provide full control of seizures. Corpus callosotomy (separating the brain’s two hemispheres) and Vagus Nerve Stimulation (VNS) may help children who have uncontrollable drop attacks.
Drug Therapy for Lennox–Gastaut Syndrome
Anticonvulsant therapy often fails to achieve seizure control in LGS. No single drug exists that is effective for the various types of seizures seen in LGS.
Drug therapy focuses on suppressing the seizures, often with multiple medications that may lead to toxicity and impair a child’s cognitive and behavioral development. Anticonvulsants that help one type of seizure may aggravate another type.
To minimize the risks of negative side effects of anticonvulsants, the physician may need to closely monitor all medications given to children with LGS.
Diet Therapies May Help Control Seizures in LGS
Two diets, the Ketogenic diet and the Modified Atkins Diet may help some children with Lennox-Gastaut Syndrome.
- Ketogenic diet – the ketogenic diet is a high fat and low carbohydrate diet often used when children have drug resistant seizures.
- Modified Atkins diet – this diet is similar to the ketogenic diet but is less restrictive.
According to their website, The Children’s Hospital of Pittsburgh uses both diets and is likely to be using the either the Ketogenic or Modified Atkins diet with 35–50 children at any time.
A combination of therapies, all closely monitored and tailored to a child’s individual needs, may offer the best possibilities for controlling seizures and helping each child with LGS reach her or his maximum potential for development.
Sources
Arzimanoglou A MD, et al; Lennox-Gastaut Syndrome: A Consensus Approach on Diagnosis, Assessment, Management and Trial methodology; The Lancet Neurology, vol 8 i1 pgs 82-93, Jan 2009
Devinsky O MD; A Guide to Understanding and Living With Epilepsy; F.A. Davis Company, 1994
Dulac O Engel J; Lennox-Gastaut Syndrome; International League Against Epilepsy[LINK], Apr 30, 2005
Freeman J MD, et al; Seizures and Epilepsy in Childhood: A Guide for Parents; Johns Hopkins Press, 1997
Glauser, TA MD; Kao A MD,(ed);Lennox-Gastaut Syndrome; Emedicine.Medscape; Article 1176735-overview, Jun 15 2011
Resources
Disclaimer: This article is only for informational purposes and not meant to diagnose or treat any disease or condition. If you have any concerns, consult you doctor or health care professional.
Zoe Langley - Zoe Langley is a writer living in Kentucky. She is a past winner of the Seattle Writers in Performance Award. She has a passionate ...
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