Epilepsy Ontario :: Recognizing Infantile Spasms

Recognizing Infantile Spasms

by Frank Wang
The slightest deviation from normal behaviour in a child can trigger an alarm in the mind of a parent. A single sneeze is automatically assumed to be caused by the flu. A little daydream is regarded as a sign of Attention Deficit/Hyperactivity Disorder. Although most "abnormal" behaviours are in fact normal, it is always best to be cautious. When it comes to babies, parents can be particularly paranoid. Babies become very unpredictable as their brains develop and they begin exploring their environments. During this period of development, babies are fine tuning their motor systems and sometimes exhibit jerky movements. Although these jerks are usually normal baby behaviours, on rare occasion they are signs of a special kind of epilepsy in infants known as infantile spasms.

What are Infantile Spasms?
Infantile spasms (IS) are a form of epilepsy, or seizure disorder, in infants. The disorder is strongly associated with infants between the ages of four and six months. The first case was described by the English doctor William James West in 1841 who observed the spasms in his own son. Later on, the set of symptoms he described was named West syndrome, after him. It is important to distinguish between West syndrome and infantile spasms, although the two are often mistakenly used interchangeably. To be diagnosed with West syndrome, the infant must show developmental delay and a chaotic kind of brain wave activity called hypsarrhythmia, in addition to the spasms. Thus, a diagnosis of infantile spasms does not necessarily mean a diagnosis of West syndrome, although the therapeutic approach is the same for both disorders. It is also important to note that IS is not the only form of epilepsy in infants.

What are signs of infantile spasms?
Normal babies have movement jerks all the time. The causes of these jerks range form hiccups to cramps. One of the features that separates the spasms of IS from normal jerks or movements is the time and frequency at which the jerks occur. In IS, similar to other epilepsies, the spasms tend to cluster and/or occur right after waking up from sleep or a nap.

Age is another important factor. Although the exact mechanism is unclear, it is believed that IS is associated with major brain developments that occur at around four to six months of age. During this period, the infant's brain is often restructuring its neurons to allow higher cognitive functions. There will be many chemical messengers present in the brain to orchestrate this development. As a result, certain brains that are diseased or sensitive to these neuro-chemical changes may be more susceptible to seizures or abnormal neuron discharges during this time. Isolated epileptic seizures have not been shown to harm the neurons directly, but they could affect how the neurons connect to each other, expression of ion channels, and microelement influx into the cell. These effects, if prolonged, can cause structural and functional neuronal damage. Infants that suffer IS, if left untreated, have a higher risk of developmental delay.

What are the treatments?
The goal of IS treatment is to stop the spasms. The first line of treatment is drug therapy. Vigabatrin has been found to be particularly effective against IS in around 60 to 65% of patients. It has proven to be even more effective in patients whose infantile spasms are secondary to a genetic condition called tuberous sclerosis. However, like all drugs, Vigabatrin has side effects. The most common side effect is sedation, which usually lasts only a few days. In some cases prolonged use of vigabatrin can cause toxins to be concentrated in the retina, one of the eye layers. Symptoms can include "tunnel" vision in which the patient loses sight in the peripheral (outer) fields. These side effects restrict the use of vigabatrin for many neurologists. Some protocols use it for a limited time period of 6 months; however, the exact time must to be discussed with the physician and is subject to other variables such as underlying disease, and seizure response.

If vigabatrin is found to be ineffective in a patient, then neurologists may move on to hormone treatment with Adrenocorticotropic Hormone (ACTH). ACTH is another type of treatment for this type of epilepsy. In this therapy, ACTH causes blood adrenal gland steroid (cortisol) levels to rise. Increased appetite and irritability are common side effects. Under ACTH, babies usually gain weight and look very "pudgy". The most concerning side effect is the immunosuppressant effect of high steroid levels. Therefore, any signs of infection need to be treated promptly, especially since some of the normal body red flags for acute infection, such as fever, may not be as apparent when this hormone is being used.

If none of the above treatments work, neurologists may resort to broad spectrum anti-epileptic drugs. These drugs are found to be effective against a wide range of epilepsies and not specific to IS. Furthermore, there are other treatment methods, but they are rarely used because most of the patients respond to drug therapy.

What can parents do?
Parents should be informed of the signs of IS and learn how to distinguish the symptoms from normal baby behaviour. Since IS movement jerks often occur right after waking, keeping track of the time when the baby is having movement jerks, if any, would be a good start. In addition, note if the spasms tend to be clustered. Clustered spasms can be a sign of IS. Age is also an important factor, since IS is associated with infants from around four to ten months of age. Noting the above factors will usually separate infants that are high risk for IS from infants that are experiencing normal behaviour such as hiccups, sleep myoclonus (sudden muscle twitch), colics (spasmodic abdominal pains), or constipation and bowel movements.

Another effective tool would be a video camera. Take a home video of the infant during these spasms and show it your doctor. A home video can add to the history that parents give and may even bring in clues that have been missed. The infant's medical history is another important factor. Infants that have a neurological disorder such as tuberous sclerosis or a history of birth asphyxia, are at a higher risk of IS compared to healthy infants. Usually, neurologists will perform a variety of tests to look for neurological abnormalities in infants suspected of IS.

All of the above tools can help your doctor make a faster, more accurate diagnosis. In all cases, an electroencephalogram (EEG) will be requested by your doctor. In many cases of epilepsy the final objective is to stop the seizures alone. In infantile spasms however, normalizing the EEG is pursued as part of the therapeutic goal.

What current research is being done on infantile spasms?
Research labs around the world are developing new ways to treat IS and epilepsy. Not having an animal model has limited to some degree the research on this condition. Most anticonvulsant drugs are first trialed as add-on therapy for refractory partial epilepsy in adults. Vigabatrin was not initially designed for IS, but was found to be effective against this disorder later on during clinical trials. However, the future is very promising. Many research labs are attempting to develop an animal model for IS. If a model's validity is confirmed, it could catalyze the therapy discovery process. New treatments could be tested and brought into the clinic at a much faster rate.