Rasmussen syndrome

This is a very rare form of brain malfunction which may occur at any time during childhood. It most commonly affects children aged three to 11 years of age.

It is not known what causes the problem but what is known is that brain cells in one hemisphere (one half of the brain) become very inflamed and also swollen. It is not known why the brain becomes inflamed.

There is no evidence of a viral infection in the vast majority of cases. Very occasionally research has shown that 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.

Symptoms

The inflammation causes the nerve cells in the brain to malfunction (not work properly), 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 control centres in the brain lies in the back part of the frontal lobe. Many of the seizures involve simple partial motor seizures causing rhythmical jerking of the arm and/or leg on the opposite side of the body.

The seizures are usually very difficult to control with medication. After a few months of these seizures 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.

Diagnosis

All the investigations are usually normal except for the electroencephalogram (EEG) and the brain scans.

The scans, particularly the magnetic resonance imaging scan (MRI), become abnormal after months or years. It usually shows evidence of irreversible damage to nerve cells caused by the inflammation. This shrinkage of brain matter is known at atrophy.

Treatment

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 have to be removed – this is called a hemispherectomy or hemispherotomy. Here, surgery can offer a cure, but these instances are rare.

Prognosis (outlook)

After a period, usually of some years, the inflammatory process seems to stop of its own accord with no further progression. 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. 

Support organisation

Contact a Family, 209-211 City Road, London, EC1V 1JN, telephone 0808 808 3555, www.cafamily.org.uk

Because this page is written by an epilepsy healthcare professional and not by Epilepsy Action, it falls outside the requirements of the Information Standard.