West Syndrome (Infantile Spasms)

4th June 2020

Named after Dr William West, West syndrome, also known as infantile spasms, are a type of seizure that start early in life and are specific in nature, as are all syndromes. West syndrome is diagnosed when a child has a very specific type of seizure and age of onset combined with an electroencephalogram (EEG) pattern known as ‘hypsarrhythmia’. EEG tests examine the brain’s electrical activity and this particular pattern is very characteristic of West syndrome. 

Dr West actually first diagnosed the condition in his own 4 year old son back in 1841. Today, it is known that West syndrome affects approximately 1 in every 2,500-3,000 children, which is around 350-400 children in the UK each year. 


In around 9 out of 10 cases, infantile spasms will begin to happen during the child’s first year, most commonly this is between 3 and 8 months of age. These spasms are often infrequent and therefore the diagnosis can be made late as a result. Because of the pattern of the attacks and the cry the child gives during, parents often receive a misdiagnosis of colic. 

The spasms themselves are characterised by sudden flexion and a tonic stiffening of the body, arms and legs. Sometimes the limbs are flung outwards, which is known as an extensor movements. Usually both sides of the body are affected equally and a mixture of flexor and extensor movements can be present. 

These episodes will typically last for just 1 or 2 seconds, with a pause for 5 to 10 seconds, followed by another spasm. This pattern can be difficult to detect and can be over in a matter of seconds. Spams may occur in clusters, which can make them more noticeable. 

Babies who have West syndrome can become irritable. They may also go off feeding and their sleep pattern can change so they sleep more during the day and less at night. Children with West syndrome may have slowed development, many parents say the child presents as though they cannot see, but they are not thought to be visually impaired. 


A detailed account of the spasms alongside an electroencephalogram (EEG) test will most likely provide a diagnosis of West syndrome. The EEG test will show a very disorganised pattern, known as a ‘hypsarrhythmia’ and is always abnormal in children with West syndrome, however, this abnormality may only be detected when the child is asleep. For this reason, the child may have to undergo two seperate EEG tests, one whilst awake and the other whilst asleep. 

Additional tests may be used to confirm, these include blood and urine tests, as well as spinal fluid investigations to try and find the underlying genetic cause of the syndrome.  


Corticosteroids are commonly used to treat West syndrome, alongside a variety of anti-epileptic medications, including vigabatrin, nitrazepam, sodium valproate and zonisamide. Where steroids are used it’s important to be extremely cautious because there are possible adverse effects. 

In some cases, the ketogenic diet may be recommended to help control seizures, which is a specialised low carbohydrate, high fat diet. 


Around 70% of children with West syndrome will have their spasms fully controlled through the use of AEDs or other treatments. The key to control is to discover the underlying cause of the syndrome. Many children who have West syndrome will unfortunately go on to experience other kinds of seizures later on in life, and some develop another syndrome known as Lennox Gastaut syndrome

Learning difficulties are common in children with West syndrome, however these can range from mild to severe. The severity of learning difficulties will likely be dependent on the underlying cause of the syndrome. An early diagnosis and finding the optimal treatment option may ensure the child has the best developmental outcome.