What Is Lennox-Gastaut Syndrome?

Lennox-Gastaut syndrome accounts for between 3 and 6% of children with epilepsy, being more common in boys than in girls. It usually begins between 3 and 5 years old and in almost half of cases results from an unknown cause. Clinically, in addition to epileptic seizures, cognitive deterioration and a slow spike-wave pattern usually appear. In almost all cases, cognitive deterioration is progressive.

Affected people have learning difficulties, memory loss and psychomotor disorders. Half of those who reach adulthood do so with a significant disability and only a very small percentage of those who do are able to fend for themselves. Lennox-Gastaut syndrome is accompanied by mental retardation in all diagnosed cases.

About  5% of patients with Lennox-Gastaut syndrome die from this disorder  or associated problems before the declared disease reaches more than 10 years. The disorder often continues during adolescence and adulthood, generating multiple emotional problems and disabilities, so current treatments are focused on improving the quality of life of patients.

The main symptoms of Lennox-Gastaut syndrome

Lennox-Gastaut syndrome is a severe type of childhood epilepsy that  impairs intellectual abilities and developmental problems. Seizures usually start before the age of 4. The types of seizures experienced by those who suffer from it vary, but generally are seizures:

• Tonics  : stiffness of the body, deviation of the eyes and dilation of the pupils with altered respiratory patterns.

• Atonic  : brief loss of muscle tone and consciousness causing sudden falls, which can be dangerous as they are sudden and can lead to injury.
• Atypical absence  : periods during which they are absent and remain fixed on a point without responding to external stimuli.
• Myoclonic  : sudden muscle twitching.

We can observe periods when seizures are frequent, as well as short periods when no epileptic seizure occurs. The majority of children with Lennox-Gastaut syndrome  experience some degree of impaired intellectual functioning  or information processing, as well as developmental delays and behavioral disturbances.

Problems associated with the disease

This syndrome is  usually associated with serious behavioral disorders such  as:

• Hyperactivity
• Aggressiveness
• Autistic tendencies
• Personality disorders
• Frequent psychotic symptoms

Health complications of those who suffer from this syndrome also include neurological disorders such as tetra-paresis, hemiplegia, extra-pyramidal disorders, and delay in motor development. Earlier onset is possible, and it is then impossible to determine whether Lennox-Gastaut syndrome is a seamless continuation of West syndrome. However, the syndrome can appear in the second half of childhood, adolescence and even in adults.

Patients may present with the combination of slow spike-waves with EEG, mental retardation, difficult-to-treat seizures, and poor response to anti-seizure drugs. Children are subject to a  reserved prognosis with regard to their mental development  and the course of their seizures. However, Lennox-Gastaut syndrome is not a pathological entity, since very diverse causes can generate it.

Causes and treatments

The most common causes of the appearance of the syndrome are:

• Genetic disorders
• Neurocutaneous syndromes
• Encephalopathies after hypoxic-ischemic lesions
• Meningitis
• Brain malformations
• Perinatal asphyxia
• Severe brain injury
• Central nervous system infection
• Hereditary degenerative or metabolic diseases

In 30 to 35% of cases , the causes behind the syndrome remain unknown. Treatment is very difficult, Lennox-Gastaut syndrome being very resistant to conventional treatment. The drugs of first choice are valproate and the benzodiazepines (clonazepam, nitrazepam and clobazam) and are prescribed either according to the types of seizures most frequent.

Generally, the treatment designed to reduce or alleviate symptoms is not just one drug, but the use of several simultaneously such as lamotrigine, valproate or topiramate. We may see improvement in some children, but  usually they show tolerance to the drug over time so that seizures get out of hand with the treatment when previously it at least partially controlled them.

Treatment for the syndrome is lifelong because there is no cure. The main objective is to improve the quality of life by reducing the frequency of attacks, although full remission is not possible. In addition to medication, there are other  treatments such as the ketogenic diet,  vagus nerve stimulation, and surgical treatment.

There is currently a hopeless long-term prognosis, with 10% mortality before the age of 11. The good news is that researchers are working every day to improve this data and that the advancements, thanks to technological advancements, have been remarkable in recent years.

Syndrome data

All the authors agree on  the particular and evocative nature of the seizures observed, as well as on their high frequency. However, important differences appear when it comes to specifying the types of crisis. In fact,  the most frequent is that these crises are brief, which can even go unnoticed  .

The alteration of the psyche is usually severe, both in terms of intelligence and personality, constituting a constant feature of the syndrome. We can consider  mental retardation to persist or worsen in most cases. It is likely that this mental retardation is partly related to brain atrophy, confirmed by gas encephalography or computed tomography.

On the other hand, the lack of learning seems to be linked to the frequency of seizures, to the existence of lasting confusional episodes in the form of ill and psychotic states, not to mention exclusion from school and therapeutic overdose. The assessment of the mental level is frequently affected by alterations characterized by disorders of the prepsychotic or psychotic personality of the child (infantile autism).

Bibliographical references

David, P., García, V., and Meneses, S. (2014). Lennox-Gastaur syndrome, an updated review. Chilean Epilepsy Journal. 3, 42-45.

Herranz JL, C de Casas-Fernández, J de Campistol, J de Campos-Castelló, M de Rufo-Campos, Torres-Falcón A, et al. (2010). Lennox-Gastaut syndrome in Spain: retrospective and descriptive epidemiological study. Rev Neurol.  50, 711-7.

Valdivia Álvarez, C., and Marreno Martínez, P. (2012). Etiological characterization of symptomatic Lennox-Gastaut syndrome. Cuban Journal of Pediatrics. 84 (1), 22-32.

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