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West syndrome (infantile spasms)

What is a syndrome?

A syndrome is a group of signs and symptoms that, added together, suggest a particular medical condition. In epilepsy, examples of these signs and symptoms would be things like the age at which seizures begin, the type of seizures, whether the child is male or female and whether they have physical or learning disabilities, or both. The results of an electroencephalogram (EEG) are also used to help identify epilepsy syndromes.

Epilepsy Action has more information about seizure types, learning disabilities, and the EEG.

If you would like to know more about an epilepsy syndrome, please speak to your doctor. If you would like to know more about epilepsy in general, please contact Epilepsy Action.

West syndrome (infantile spasms)

Infantile spasms are a type of epilepsy with a characteristic age of onset (typical age when seizures start), pattern of seizures and electroencephalogram (EEG). This means that it is an ‘electroclinical epileptic syndrome’. They can also be called ‘salaam spasms’, because the appearance of the seizures is like a bowing forwards or backwards movement. The syndrome is called ‘West syndrome’ after Dr West, who first described the condition in his own four month old son in 1841. This type of epilepsy occurs in about one in 2,500-3,000 children. Every year in the UK about 350-400 children will develop West syndrome.


In nine out of 10 children with the condition, infantile spasms occur in the first year of life, typically between three and eight months old. To begin with, the attacks are usually brief and infrequent and do not occur in clusters. Therefore it is quite common for the diagnosis to be made late. The first diagnosis is often colic because of the pattern of the attacks and the cry that a child gives during or after an attack.

The typical pattern is of a sudden flexion (bending forward) in a tonic (stiffening) fashion of the body, arms and legs. Sometimes, the episodes are different, with the arms and legs being flung outwards (these are called ‘extensor’ spasms). Usually, they affect both sides of the body equally.

Typically, each episode lasts just one or two seconds, there is then a pause for a few seconds followed by a further spasm. While single spasms may happen, infantile spasms usually happen in ‘runs’ or ‘clusters’ of several in a row. It is common for babies who have infantile spasms to become irritable and for their development to slow up or even to go backwards until the spasms are controlled. These infants can also behave as if they cannot see. This improves once the spasms are controlled and the EEG has improved.


The diagnosis of infantile spasms is made by a combination of the typical features with a typical EEG. The EEG shows a very disorganised pattern called ‘hypsarrhythmia’. The EEG is always abnormal in children with West syndrome but sometimes this abnormality is seen only during sleep. Infantile spasms, like many other ‘electroclinical syndromes’, have lots of different causes. A particular cause will be found in seven or eight out of every 10 children with West syndrome.

Most children with infantile spasms will need a number of tests apart from the EEG. These include brain scans, blood tests, urine tests and, sometimes, spinal fluid and other tests in order to try to identify the underlying cause. The most important brain scan is the magnetic resonance imaging (MRI) scan.


The main treatments used are steroids or vigabatrin (Sabril). Nitrazepam and sodium valproate (Epilim) may also be used. There are different types of steroid that can be used. These are prednisolone (given by mouth), hydrocortisone (given by mouth or sometimes by injection) or tetracosactide (given by an intramuscular injection). Steroids must be used carefully as this treatment may cause some unpleasant side-effects. Vigabatrin may also be associated with some side-effects.

Prognosis (outlook)

In some children, infantile spasms respond easily to treatment, whereas in others they keep on happening. Most children unfortunately go on to have other kinds of seizures in later childhood including an epilepsy syndrome called Lennox-Gastaut syndrome. Most children also have learning difficulties and these may be mild or severe. The long-term prognosis for West syndrome, for both the spasms stopping and the child’s development and learning, depends mainly on the cause of the syndrome.

Support organisation

Contact a Family
209-211 City Road
London EC1V 1JN
Phone: 0808 808 3555

Website: www.cafamily.org.uk

Because Epilepsy Action has not written this information, it is not produced under the terms of the Information Standard. Details of the Information Standard are available from www.theinformationstandard.org

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Our thanks

Epilepsy Action would like to thank

  • Dr Richard Appleton, and Dr Rachel Kneen, consultant paediatric neurologists at Alder Hey Children’s Hospital,Liverpool,UK and
  • Dr Stewart Macleod, consultant paediatric neurologist atRoyalHospitalfor Sick Children,Glasgow,UK.

They have kindly prepared the information on this page. It is based on their own research, experience and expertise.

This information is exempt under the terms of The Information Standard.

  • Updated November 2012
    To be reviewed November 2015

Comments: read the 12 comments or add yours


Could. Anyone tell me if it correct that infantile spasms stop at around 18 months and if this is true the reasons biology behind this also should a child with infantile spasms stop meds for this problem ie vigabatrin at that age his underlying diagnosis is tubular sclerosis thanks for you help

Submitted by NicolA on


We understand that some children stop having infantile spasms, but it’s different for different children. And some children go on to develop other types of seizures. You need to discuss the decision to stop vigabatrin with your child’s specialist. They will be able to tell you about the benefits and risks for your child.

Here is some information about tuberous sclerosis and infantile spasms. You could contact the Tuberous Sclerosis Association to see if they can tell you more.

Advice and InformationServices

Submitted by Kathy@Epilepsy ... on

Hi just wondering if their is a west syndrome charity?? My lil boy has it and I want to do something to help research etc?? Any advice would be great x

Submitted by Katy trueman on

Hi Katy

I hope the information on this West syndrome page was of some help to you.

You mentioned that you want to help with research. There are different way this can be done. You could look on the research section of our website for details about Epilepsy Action’s research.

There is also an organisation called Epilepsy Research UK

If you prefer to do something connected to West Syndrome you could contact other families to see if they are aware of anything connected to this. The organisation Contact a Family (CAF) have a support network for parents of children with some of the rarer types of medical conditions and disabilities. They have details of a support group for West syndrome. You can find details of this on CAF’s website or email them at helpline@cafamily.org.uk

I hope this helps.


Advice and Information Team

Submitted by Rosanna on

How long is a child usually in hospital for when treatment starts

Submitted by richard on


There is no set time scale. It will depend on the individual child and their doctor.

If you haven’t already, you may wish to put this question to the child’s doctor.



Advice and Information Team

Submitted by Diane on

Is it possible that onset is not until a child is 20 months. My daughter had a seizure/spasm this morning when waking up they were about a second or two long and lasted almost 10 min with about 10 to 20 seconds in between. We called 911 and since she was fine when they arrived they just told her to take her in.We went to her Dr right after and should be receiving a call for an EEG by Monday. My daughter was born at 25wks and spent 5 months in the hospital before coming home. Besides chronic lung disease and feeding issues (gtube) We have been really blessed. She has meet almost all milestones. She is walking well running now, talking and even doing sign language. She loves interacting with others and is quit the little dancer.This morning was the first time something like this has ever happened. Well that I have seen. I have looked everywhere online but everything leads me back to infantile spasm.

Submitted by Jessica on

Hi Jessica

Children can develop epilepsy at any time. And doesn’t automatically start at birth, even if there have been complications.

Hopefully as well as being called for an EEG, you will be able to talk to a paediatrician. I am sorry but as we aren’t medically trained, we’re not able to say what exactly could be happening for your daughter. But I do hope you get some answers soon.


Advice and Information Team

Submitted by Cherry on

Is it not true that newborns neo nates (ie - less than 3 months old) typically have spasms because their nervous system connections are still not full formed, and these spasms may go away as the connections form. This is why newborns less than 3 months old are not considered for this condition because it is a relatively common in newborns - correct me if I am wrong.

Submitted by Mike Darco on

Hi Mike

If a baby is having infantile spasms as opposed to any other type of spasm, this can be identified in particular results of an EEG called hypsarrythmia.


Advice and Information Team

Submitted by Cherry on


My son who is nearly 7 months been having spasms for a few weeks now. Just been docs this week and they have referred me to hospital but the doc I saw at the surgery is passing it off as colic or reflux and I am almost positive it is not that as my daughter had reflux and this nothing like this. How do i go about making them believe me as when I was there he never did it. How do I get them to hurry up? How can I make them test my son for it so im not bing passed off as reflux which I no it's not. Please help.

Submitted by Angela Stapleton on

Hi Angela

Thank you for your question. It can be a worry waiting for appointments to come through. Most children will be referred to a paediatrician. The paediatrician should listen to what your concerns are and look at any evidence you have of your son’s episodes. Therefore, if possible keep a diary of his symptoms and see if you can record what you think are seizures.  If needed, the paediatrician will refer your son to a colleague with a special interest in epilepsy. Please view our information on how epilepsy is diagnosed.

You could contact your GP practice to ask what the expected waiting time is for his referral are. Or if you haven’t already, you could talk to your son’s Health Visitor. If necessary they could talk to your GP.

If we can be of any more help, please feel free to contact us again, either by email or the Epilepsy Helpline freephone 0808 800 5050.


Diane Wallace

Advice and Information Team

Submitted by Diane on

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