If your child has seizures, it could be due to this condition: West Syndrome (Source: Freepik; freepik.com)

It should be noted that not all seizures in a child means that they have epilepsy or , equally, do not mean that they have West syndrome , but rather that the seizures of this syndrome have specific characteristics that allow us to differentiate it.

What is West syndrome?

West syndrome is defined as a specific form of seizures (infantile spasms) that occur during infancy and childhood . This syndrome causes developmental delay, and tests (electroencephalogram) show a unique pattern known as hypsarrhythmia, which consists of chaotic brain waves . Infantile spasms usually develop in the first year of life, between ages 4 and 8.

The spasms that occur can range from dramatic knife movements or “salaam”, in which the whole body bends in half, to small tremors of the shoulders or movements of the eyes. By extending their arms and legs, some children also arch their backs.

The spasms usually occur when you first wake up or after eating , and can occur in groups of up to 100 spasms at one time. Every day, children can have many seizures and hundreds of spasms.

Infantile spasms usually stop around the age of five , but other types of seizures can take their place. When they become adults, instead of infantile spasms, they are called epileptic spasms.

Symptoms

Symptoms of West syndrome usually appear in the first year of life .

Involuntary muscle spasms are a symptom of epileptic spasms, caused by uncontrolled electrical abnormalities in the brain (seizures). Each involuntary spasm usually starts suddenly and lasts only a few seconds, often occurring in groups of 10 to 20 minutes.

Sudden and uncontrolled contractions of the head, neck and trunk, as well as the uncontrolled extension of the legs and/or arms, define these episodes, which can occur, as we have already said, when waking up or after feeding. Seizures vary in duration, severity, and muscle regions affected from one baby to another.

Babies also show signs of abnormal skin structure, mental decline and loss of developmental milestones, dysphagia (poor swallowing), may have trouble breathing called dyspnea , and may also have increased reflexes . Some babies may also have microcephaly , which means their skulls are decreased in size and their head circumference is relatively small.

The electroencephalogram (EEG) of infants with West syndrome is also atypical , with high amplitude and disorganized spike wave patterns indicating hypsarrhythmia. Most children have a loss of dexterity or a delay in learning skills involving coordination and muscle movement ( psychomotor retardation ). As babies with West syndrome grow, about a third of them may have recurrent seizures.

The disease often progresses to Lennox-Gastaut syndrome , which is characterized by a wide range of difficult-to-control seizures that are related to intellectual retardation.

Causes

Various diseases can induce West syndrome , such as brain damage, structural defects during brain development, genetic mutations, metabolic abnormalities, or without a valid cause.

However, in a certain percentage of people with West syndrome, a precise etiology can be determined. It can be due to trauma to brain malformations , such as cortical dysplasia. It can arise due to infections and chromosomal abnormalities such as Down syndrome. Some neurocutaneous disorders such as tuberous sclerosis complex (TSC) and/or Sturge Weber syndrome. It can also occur due to various metabolic/genetic diseases, such as pyridoxine deficiency, maple syrup urine disorder, and phlebitis, all of which are potential causes.

Tuberous sclerosis complex (TSC) is the most common cause of West syndrome . It is an autosomal dominant genetic disorder, so if the father or mother suffers from it, the baby inherits it for sure. This disorder causes seizures, eye, heart and kidney tumors, as well as skin changes. A non-functional gene can be inherited from either parent or come from a mutated (altered) gene in the affected person. Each pregnancy has a 50% chance of transferring the non-functional gene from an affected/carrier parent to the offspring. Men and women are at the same risk.

genetic factors

Many genes have been linked to West syndrome , and in almost all cases where West syndrome has been linked to a genetic mutation , it has arisen spontaneously (de novo) and has not been inherited from either parent . West syndrome is caused by mutations in at least 100 different genes , according to research. In about 5% of children with unexplained West syndrome, pieces of DNA were missing or extra: deletions or duplications, which affect numerous genes.

Recognizing the genetic cause, if any, can help families understand why their child had infantile spasms, as well as provide information about the prognosis, treatment options, and chances of recurrence for future siblings or other close relatives.

Diagnosis and treatment

When infantile spasms are seen, an electroencephalogram (EEG) is usually done to look for the abnormal brain waves of hypsarrhythmia and confirm the diagnosis. Several EEGs taken at different times in the child’s wake/sleep cycle may be necessary to detect hypsarrhythmia. To capture the actual spasms on the EEG, a prolonged EEG may be performed over several hours (up to 24 hours). The EEG may appear normal when the child is awake or in REM sleep, but only shows irregularities in light sleep or just after awakening, especially in the early phases of the syndrome, shortly after the onset of spasms.

Additional tests and imaging may be done to determine the underlying cause of the problem , so that the treatment strategy can be informed. To examine the presence of tumors, lesions, or other structural abnormalities of the brain, neuroimaging can be used. To confirm the presence of a metabolic disorder, blood tests may be done. West syndrome can be diagnosed by genetic testing to look for particular genetic reasons.

The main goal of treating West syndrome is to stop the seizures and , if necessary, correct the pattern of hypsarrhythmia on EEG . Seizures can be treated with drugs such as corticosteroids and Vigabatrin, an anticonvulsant agent. If a brain injury is confirmed to be the cause of the seizures, surgical excision of the injury may help. If an underlying metabolic disease is found to be the cause of the seizures, treating the disease may help decrease the seizures. In some circumstances, a ketogenic diet can be beneficial.

References:

Freepik (s.f.). Hand drawn flat design epilepsy illustration [Free Vector]. Freepik. https://www.freepik.com/freepik

West syndrome (2021). Genetic and Rare Diseases Information Center (GARD). https://rarediseases.info.nih.gov/diseases/7887/west-syndrome

West Syndrome (s.f.). Children’s Hospital of Philadelphia. https://www.chop.edu/conditions-diseases/west-syndrome

West Syndrome (s.f.). NORD (National Organization for Rare Disorders). https://rarediseases.org/rare-diseases/west-syndrome/ 

West syndrome (infantile spasms) (2019). Epilepsy Action. https://www.epilepsy.org.uk/info/syndromes/west-syndrome-infantile-spasms