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.
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.
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.
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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.