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Rasmussen syndrome

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 typeslearning 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.

Rasmussen syndrome

This is a very rare form of brain malfunction which may happen at any time during childhood. It most commonly affects children aged three to 11 years. It may rarely happen in children under three years of age, or in adulthood. It is not known what causes the problem. But what is known is that brain cells in one hemisphere (half) of the brain become very inflamed and also swollen. It is not known why the brain cells becomes inflamed. There is no evidence of a viral infection in the majority of cases, although research has shown that very occasionally a virus may be present. It is possible that a virus may trigger an antibody response in the brain – which then causes the inflammation and malfunction of the brain.


The result of the inflammation is that nerve cells malfunction, and this causes seizures. These seizures occur very frequently, often many times a day. They can also become continuous. This is called ‘epilepsia partialis continua’.

The most commonly affected parts of the brain are the frontal lobe and the temporal lobes. One of the motor (movement) control centres in the brain lies in the back part of the frontal lobe. So many of the seizures involve focal (partial) motor seizures. These cause rhythmical jerking of the arm and/or leg on the opposite side of the body. The seizures are usually very difficult to control with medicines.

After a variable period of time - from months to years - the child can develop a weakness of the side of the body that is affected by the seizures. This weakness is called a ‘hemiparesis’ or ‘hemiplegia’. As the seizures continue, this weakness worsens. Some children may also develop learning or behaviour problems as the condition progresses. This can be as a result of the underlying progressive nature of the disorder, the number of seizures they have, side-effects of medicines, or a combination of all three. 


All investigations are usually normal, except for the EEG and brain scans. The scans, particularly the magnetic resonance imaging (MRI) scan, become abnormal after months or years. The MRI usually shows evidence of irreversible damage to nerve cells caused by the inflammation. This shrinkage of brain matter is known as atrophy.

Epilepsy Action has more information about diagnosing epilepsy.


Seizures in Rasmussen syndrome can be difficult to treat. There is no particular epilepsy medicine that seems to be more effective than another. Commonly used epilepsy medicines include carbamazepine, levetiracetam, topiramate and clobazam. Medicines to suppress or alter the immune system may also be used. These include steroids and/or azothiprine.

For some young people, the disorder is confined to a part of the brain that can be safely removed, particularly the temporal lobe. Occasionally, the whole of one side of the brain may be removed or disconnected – this is called a hemispherectomy or hemispherotomy. Here, surgery can offer a cure. However, a child with Rasmussen syndrome having this surgery will be left with a permanent weakness (hemiplegia). So it is not an easy decision. But if there is a progressive weakness down the affected side, difficult to manage epilepsy and loss of cognitive (learning) skills, doctors may consider surgery.

Information about treatments for children can be found on the Medicines for Children website.

There may be research studies open that are relevant to this epilepsy syndrome. Your child’s doctor will be able to discuss this with you.

If your child has this syndrome they may have prolonged or repeated seizures. Your child’s doctor will discuss a ‘rescue’ or emergency care plan with you to treat any prolonged or repeated seizures.


After a period, usually of some years, the inflammatory process seems to stop of its own accord and doesn’t get any worse. Unfortunately, however, the nerve cells that have been injured continue to malfunction. As a result, the epilepsy may continue, though there is a better chance at this stage of bringing it under control. The inflammation may be fairly widespread within the substance of the brain. Most children with this condition also have a hemiparesis (weakness) and have some learning difficulties. This makes an assessment of the child’s educational strengths and weaknesses very important. In the light of this assessment, appropriate help and encouragement can be offered at school.


Contact a Family
Freephone helpline (UK only): 0808 808 3555
Website: cafamily.org.uk
Email: info@cafamily.org.uk 

HemiHelp is a charity providing support and information to people with hemiplegia and their families in the UK.
Website: hemihelp.org.uk


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 at Royal Hospital for 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 December 2012
    To be reviewed December 2015

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