By S.M. Pueschel, M.D., Ph.D., J.D., M.P.H., East Greenwich, RI
It is well known that seizure disorders occur more often in persons with Down syndrome than in the general population. Several studies reported that eight to 10 percent of individuals with DS have some form of seizures.
A particular form of seizure called infantile spasms or West syndrome is observed in babies with DS between the ages of five to 10 months. These children with infantile spasms display frequent jerking body movements that involve the child’s trunk musculature, head, arms and legs. The sudden forward flexion movements cause the infant to double over at the waist and, therefore, are sometimes referred to as jackknife seizures or salaam attacks. The spasms typically occur in clusters, and several dozen clusters often are observed each day. Cessation or regression of intellectual and motor developments usually accompany these seizures.
The brain wave or electroencephalographic (EEG) patterns in infantile spasms are called hypsarrythmia. They show random, high voltage slow waves and spikes arising from multiple foci and spreading to all areas of the cortical brain.
In most instances the cause of infantile spasms is not known. Some children have had a birth injury that may have triggered the seizure disorder. Several decades ago, one author, Coleman, reported that infantile spasms are due to the administration of 5-hydroxytryptophan. However, subsequent investigations refuted Coleman’s assertion. Another author, Neville, thought that a brainstem disorder causes infantile spasms. As mentioned before, in most children we do not know the seizure disorder’s cause.
Various treatment approaches are used in patients with infantile spasms. The most effective therapy requires injections of adrenocorticotropin hormone (ACTH) over several weeks. A newer medication recommended for treatment of infantile spasms, vigabatrin, is said to show good results. This drug, however, is not available in the United States. Other medications that have been used are valproic acid, clonazepam, phenobarbital and others.
It is important that infantile spasms are recognized early and that treatment is started as soon as the diagnosis has been made. Delaying treatment means a less favorable outcome. With appropriate therapy there is usually cessation of seizure activity and normalization of EEG pattern.
In general, the outcome of effective treatment in children with DS is better than in children who do not have this chromosomal disorder. Children without DS often will have significant sequelae such as developmental delay and behavior problems.