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Lennox-Gastaut Syndrome (LGS)

By Susha Cheriyedath, MSc

Lennox-Gastaut syndrome (LGS) is a severe type of epilepsy characterized by many types of seizures, mainly drop and stiffening seizures. LGS can be a result of malformations in the brain, head injury, perinatal asphyxia, infection in the central nervous system, and inherited metabolic or degenerative disorders.

Approximately 2-5% of childhood epilepsies are said to be LGS. Intellectual development is affected to some degree in most children with LGS. EEGs in affected children show classic spike-wave bursts and background slowing at frequencies of 2.5/s or less. The cause of this childhood disorder is unknown in 30-35% of children. Children with LGS often require life-long treatment for severe seizures that are very hard to control.

Symptoms of LGS

LGS symptoms usually start during infancy or early childhood. Seizures caused by electrical disturbances in the brain are commonly seen in affected children. Seizures usually start when the child is less than 4 years of age and the type of seizure experienced can vary from one patient to another.

Patients usually experience periods of frequent seizures and relatively seizure-free intervals. Other complications of this disorder include intellectual as well as behavioral problems, which affect the child’s quality of life considerably. LGS persists in adulthood though the presentation of symptoms changes as the child ages.

Types of Seizures

Different types of seizures seen in LGS patients include the following:

Tonic Seizure

These cause muscle stiffening, upward eye deviation, pupil dilation, and stressful respiration. Body can slightly bend and arms or legs are flexed with spasms in the face muscles. Tonic seizures usually last a few seconds to a minute and are common during sleep, though they can happen when the patient is awake and cause falls. The patient may even lose consciousness for a brief period.

Atonic Seizure

These cause sudden and temporary loss of muscle tone. They cause the individual’s head to drop and induce posture problems. They are also called drop attacks and can result in head or face injury because of unexpected falls.

Atypical Absence

These cause unresponsive staring spells in patients during a period of unconsciousness. This type of seizure is mild and often starts and ends abruptly – in fact, the patient resumes normal activity without any memory of the staring episode. In children with developmental delays, these episodes may even go unnoticed.

Myoclonic Seizures

These cause sudden, abnormal muscle jerks in affected individuals. These can occur in conjunction with absence seizures.

Treatment of LGS

In recent years, many new approaches to LGS treatment have emerged. While there is still no cure for this syndrome, children affected by LGS now have more treatment options to choose from.

Treating LGS is very tough since the seizures or intellectual changes don't always respond to medications. Anti-epileptic drugs such as lamotrigine, valproic acid, felbamate, and topiramate, and other medications like clonazepam, clobazam, and rufinamide, are used to provide partial relief from seizures or injuries caused by falls during seizures. Sometimes children respond well to a drug initially only to become resistant to it later and may have uncontrollable seizures.

A key component of seizure care involves rescue therapies that are given in order to stop or control seizures. An implanted pacemaker is often used to stimulate the vagus nerve in the neck and thus control seizures in LGS patients. Some people benefit from dietary therapies also.

Rarely, a surgery called the corpus callosum surgery that separates the two halves of the patient’s brain is performed to reduce seizures as well as injuries. However, it is clearly very complicated.

Prognosis

Prognosis varies from one LGS patient to another. No cure has been found yet for this condition and complete recovery from seizures and other developmental complications is very rare.

Reviewed by , BSc (Hons)

References

Further Reading

Last Updated: Nov 4, 2016

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