This information is for people affected by or concerned about infantile spasms, including parents and carers. Infantile spasms are also known as West syndrome. On this page we talk about how infantile spasms are diagnosed, what causes them, symptoms, treatment options and long-term outlook.
Use this page as a general guide and speak to a health professional for more information and support.
On this page
What are infantile spasms (West syndrome)?
Infantile spasms are a type of epilepsy that develops within the first year of life, usually between four and eight months old. Infantile spasms usually stop by age four or five years.
Infantile spasms are a serious, but rare type of epilepsy. About one in 3,000 children in the UK develop infantile spasms each year.
What causes infantile spasms (West syndrome)?
For most children diagnosed with infantile spasms, the cause can be identified.
Causes may include:
- Developmental problems affecting the structure of the brain
- Problems just before or during birth, which cause a lack of oxygen to the brain (asphyxia)
- Having certain infections as a baby, such as meningitis
- Genetic conditions such as tuberous sclerosis
- A change (mutation) in a gene
For a small number of children who have infantile spasms, the cause is unknown. More research is needed to understand why they happen.
What are the signs and symptoms of infantile spasms?
Children with infantile spasms experience regular spasms. Spasms can often happen in clusters and may last for several minutes.
Seizures usually happen when the child is waking up, after either a night sleep or daytime nap. At first, infantile spasms may be subtle and hard to spot. They can sometimes be confused with other normal baby behaviours or colic.
As the seizures start, children who have infantile spasms may suddenly jerk and their muscles will then become stiff. This may cause them to bend forward with their arms or legs stretched out.
Other signs and symptoms to look out for include:
- being less responsive in the days or weeks before a spasm
- being irritable and have problems sleeping or eating
- losing interest in things they usually enjoy, such as playing with toys.
Children who have infantile spasms may also experience delays in their development or show signs of autism.
How are infantile spasms diagnosed?
If you think a child under the age of two is having infantile spasms, contact their doctor straight away. They should be referred to a paediatrician (a doctor who specialises in child health), within 24 hours.
The doctor will carry out different tests to check if the child is having infantile spasms. Treatment should be started straight away to help control them.
Tests for diagnosing infantile spasms
Tests may include:
- An EEG (electroencephalogram) sleep test – a painless test that uses small sensors attached to the scalp, while the child sleeps, to pick up the electrical signals produced by the brain
- An MRI (magnetic resonance imaging) scan – a scan that uses magnetic fields and radio waves to produce images from inside the body
- Blood, urine or genetic tests
Treatment for infantile spasms
It is important for infantile spasms to be treated as quickly as possible with the most effective medicines.
Remember that everyone is different and what works for one person might not work well for someone else. People who have infantile spasms may have to try a few different medicines until something works well.
Talk to a doctor about treatment options and what might be suitable. They should explain the risks and benefits of each treatment, including any possible side effects.
First treatment options
For infantile spasms that are not caused by tuberous sclerosis, the first treatment that will be offered is a combination of:
- High-dose oral prednisolone – a steroid medication that comes as tablets, that you swallow.
- Vigabatrin (also known as Sabril) – a medication that comes as granules in a sachet, that you mix with water and drink.
For infantile spasms that are caused by tuberous sclerosis, or if the child is at risk of getting side effects from prednisolone, then vigabatrin may be offered as a treatment on its own.
If vigabatrin does not work after one week, then the child’s doctor may suggest trying a high-dose of oral prednisolone as an add-on treatment. Or, if infantile spasms still do not stop, the vigabatrin dose may be increased.
During treatment, the child’s blood pressure and levels of glucose (sugar) in their urine should be checked weekly.
Monitoring side effects
Before starting treatment, specialist doctors involved in the child’s care should discuss any possible side effects with you.
Parents and carers should also receive a steroid card and information about when and how to seek medical help for side effects.
If you’re not sure about anything, or you’re worried about side effects, always talk to a healthcare professional. They are there to help and support you.
Second treatment options
If the first treatment options for infantile spasms do not work, further treatment options will be tried.
The child’s doctor may suggest trying one of the following treatment options:
- Ketogenic diet – a special type of diet that is high in fat and protein, but low in carbohydrates. It can work well at reducing the intensity and frequency of seizures.
- Levetiracetam (also known as Keppra) – a medicine that comes as a tablet, liquid or granules, that you swallow.
- Nitrazepam (also known as Mogadon) – a medicine that comes as a tablet, that you swallow.
- Sodium valproate (also known as Epilim) – access to this treatment is limited. [see more information below]
- Topiramate (also known as Topamax) – a medicine that comes as a tablet or capsule, that you swallow.
If one of these options does not work, then another treatment option can be tried.
Sodium valproate
In January 2024, new rules were introduced for prescribing sodium valproate.
Two specialists are now needed to approve:
- New or ongoing valproate treatments for girls and women.
- New valproate treatments for boys and men
The specialists must agree that your epilepsy does not respond to other treatments and the benefits of treatment outweigh the risks.
For girls and women, valproate can seriously harm an unborn baby when taken during pregnancy.
For boys and men, valproate may cause infertility. Some people’s fertility may return when their treatment is stopped or reduced. There is also some evidence that valproate can cause harm in the testicles of animals, but it’s unclear what this means for humans.
Never stop taking valproate before talking to your specialist first. Not taking medication as prescribed can increase the risk of a seizure.
Your epilepsy specialist will let you know when your treatment is due to be reviewed.
If you are planning a pregnancy it is important to speak to your healthcare professional as soon as possible about your treatment options.
If you have any questions or concerns about valproate, please speak to your healthcare professional.
Find out more about sodium valproate in the MHRA’s patient guide.
Find out more about Anti-seizure medications, contraception and pregnancy.
Follow-up care
Children under two years with infantile spasms should be reviewed at least weekly during treatment. And they should have their sleep EEG repeated two weeks after they’ve started treatment.
When the infantile spasms have stopped, they should be reviewed monthly and have their sleep EEG repeated if spasms start again or there are other concerns.
What’s the long-term outlook?
For most children with infantile spasms, the long-term prognosis (outlook) is poor, but early treatment can help. Medicines help to control spasms in about seven out of ten children.
Many children with infantile spasms will have moderate to severe learning difficulties and some degree of developmental delays, including autism.
Even if a child’s infantile seizures are well controlled by medication, many will go on to develop other types of seizures in later life, such as Lennox-Gastaut syndrome.
Living with infantile spasms and getting support
Infantile spasms are a serious but rare form of epilepsy. It can be difficult and upsetting for parents or carers to manage a child’s learning difficulties as well as trying to control infantile spasms.
Talk to the child’s doctor for help on how to support them well. And talk to your own doctor if you need support for yourself. If you’re caring for someone who has infantile spasms, it’s important that you look after yourself and get the support you need.
You may find it helpful joining an in-person or online support group, where you can listen to or share experiences with other people who understand what you’re going through.
Other useful organisations
UK Infantile Spasms Trust (UKIST)
www.ukinfantilespasmstrust.org
An organisation that supports children and families affected by infantile spasms.
