What is Infantile Epileptic Spasms Syndrome (West Syndrome)?
Infantile Epileptic Spasms Syndrome (IESS) is a type of seizure disorder that mostly occurs in babies during their first year. It used to be known as West syndrome, after William West who first identified it back in 1841. IESS is characterized by specific changes in the baby’s brain activity (detected through EEG tests), known as hypsarrhythmia. It is also commonly linked with delays or setbacks in the baby’s developmental progress.
Recently, the definition of this disorder has been expanded to include cases that don’t fit perfectly within the original criteria for West syndrome. It’s for this reason it’s now also called Infantile Epileptic Spasms Syndrome or IESS.
Medical professionals have been studying infantile spasms for over 170 years to better understand its causes, how it develops, what symptoms to look out for, and how to diagnose it. Recognizing the signs of this condition early on and starting treatment as soon as possible is very important, which we’ll discuss more about below.
What Causes Infantile Epileptic Spasms Syndrome (West Syndrome)?
Infantile spasms, a type of seizure disorder in babies, can be grouped into two main categories: symptomatic and cryptogenic. The International League Against Epilepsy (ILAE), a global organization of healthcare professionals and scientists, has suggested an additional subcategory of cryptogenic known as idiopathic infantile spasm.
Symptomatic infantile spasms are those where a specific cause can be identified or there is a significant developmental delay at the onset of the spasms. About 60% to 70% of all symptomatic infantile spasms fall into this category. These can further be divided based on when they occur – before birth (prenatal), around the time of birth (perinatal), or after birth (postnatal).
Before birth, these spasms can be caused by abnormal development of the brain known as CNS malformations (accounting for 30% of cases). Other causes include skin and nervous system disorders such as tuberous sclerosis complex, variation in chromosomes (like Down syndrome), certain genetic alterations, metabolism defects of birth , and infections contracted before birth like toxoplasmosis and Zika virus.
In the period around birth, the causes can include lack of oxygen to the brain and low blood sugar, which are linked with infantile spasms. Low birth weight is also a common factor among children with infantile spasms. So far, prematurity has not been found to contribute to this condition.
In the time after birth, infantile spasms can be caused by traumatic injury, near drowning, tumors or infections of the central nervous system, which include brain and spinal cord.
Cryptogenic infantile spasms, on the other hand, do not have any identifiable cause. They are characterized by a condition where there are no other types of seizures, normal health check results, and no abnormalities detected in brain scans and in the pattern of brain’s electrical activity. They make up about 10% to 40% of all cases, and generally have a better prognosis compared to symptomatic spasms.
The ILAE has proposed an additional category, idiopathic, for those spasms where the child’s development has been normal before the onset of spasms. The health check and brain imaging results are normal, and there are no noticeable abnormal brain wave patterns.
Risk Factors and Frequency for Infantile Epileptic Spasms Syndrome (West Syndrome)
Infantile spasms is a rare and distinct disorder that typically emerges between the first week of life and 4.5 years. The average age when it first appears is between 3 to 7 months. It’s estimated that every year, around 2,000 to 2,500 new cases show up in the United States. While it appears to potentially affect more males than females at a ratio of 60:40, the research isn’t clear cut. What we do know is that it exists across all ethnic groups and that in 1% to 7% of cases, there is a family history of some form of epilepsy.
Signs and Symptoms of Infantile Epileptic Spasms Syndrome (West Syndrome)
Infantile spasms is a condition that often begins in infancy or early childhood. This condition is known for sudden spasms that affect the neck, trunk, and limb muscles. Children with this condition are usually less than a year old, with most cases occurring between 3 to 7 months of age. These spasms may involve bending or stretching movements, which could appear as head bobbing or body crunching.
There are usually two phases in a spasm: the first phase is sudden, brief contractions of one or more muscle groups that last less than 2 seconds. This is followed by a less intense second phase lasting anywhere between 2 to 10 seconds. Infants may experience a few or more than a hundred spasms in clusters that can last for a duration ranging from less than a minute to 10 minutes.
Infantile spasms often occur during the day or when a child is awake. Some signs that may occur with the spasms include motor arrest (lasting up to 90 seconds), abnormal eye movements or eye deviation, and changes in breathing patterns. There’s usually a significant delay in development with loss of motor and cognitive abilities. This may look like an infant struggling with reaching developmental milestones like rolling over, sitting, crawling, or babbling. Parents may also observe that their child becomes less interactive, shows fewer social smiles, or becomes increasingly fussy or silent.
The condition typically develops in stages:
- The first stage is mild, with isolated spasms occurring infrequently, paired with some developmental regression.
- The mild stage then progresses to a more severe stage where spasms increase in frequency and clustering. Here, the developmental regression noted initially becomes more pronounced.
- In the last stage, the frequency and severity of spasms decrease progressively. The spasms may disappear completely but could be replaced with other types of seizures.
It’s important for healthcare professionals to identify and promptly begin diagnostic testing for infantile spasms. Recognizing and treating this condition early significantly influences its prognosis.
Testing for Infantile Epileptic Spasms Syndrome (West Syndrome)
When a baby is suspected to have infantile spasms, a specific type of seizure disorder, the first thing a doctor will do is perform a test called an electroencephalography, or EEG. This records the electrical activity of the brain and is ideally done over a 24-hour period while the baby is in the hospital. If the results are unclear, the test may be repeated a week or two later.
The key sign of infantile spasms on an EEG is a pattern called “hypsarrhythmia.” This pattern involves very high and random electrical waves and spikes in all areas of the brain. These spikes can happen anywhere in the brain but are disorganized and never rhythmic, unlike other types of seizures.
If the EEG suggests infantile spasms, doctors will then use imaging tests to look at the baby’s brain. The best test for this is an MRI scan. In about 70% of cases, these scans can pinpoint what’s causing the spasms. If the first scan is normal but spasms continue, another MRI might be done six months later. In some cases, a special type of scan called positron emission tomography (PET scan) may be used if a more detailed view of the brain is needed.
If the EEG and MRI don’t provide a clear cause of the spasms, doctors will then do further testing. This could include testing blood, urine, or spinal fluid to check for different substances that could be causing the problem. This is to rule out any metabolic issues that could be causing the spasms. Genetic testing might also be done to see if the spasms are due to a specific inherited condition.
Despite all this testing, there are still some cases where doctors can’t identify the cause of infantile spasms. These are called cryptogenic infantile spasms and could account for 10% to 40% of cases. If your baby is diagnosed with this, treatment will begin as quickly as possible.
Treatment Options for Infantile Epileptic Spasms Syndrome (West Syndrome)
If a baby is diagnosed with infantile spasms, a condition that causes sudden, jerky movements usually in the first year of life, treatment is needed right away. Therapies may include hormones, anti-seizure medications, or changes in diet. One of the primary treatments is a hormonal therapy with corticotropin, also known as ACTH. This hormone is thought to help by suppressing another hormone that may cause seizures. However, scientists are still investigating how this works exactly.
ACTH treatment usually begins to work within 7 to 12 days after it is started. Like all treatments, ACTH has side effects including high blood pressure, immune system suppression, infection, imbalances in the body’s electrolytes, stomach issues, eye problems, heart complications, and delays in growth. Therefore, doctors usually recommend a lower dose for short periods. When a patient is receiving ACTH treatment, doctors will monitor their blood pressure, blood sugar, and levels of potassium and sodium, and will look out for signs of infection.
Corticosteroids, another type of hormonal therapy, may also be used to treat infantile spasms. However, the best preparation, dosage, and duration of treatment are yet to be established.
Beyond hormone therapy, there’s an antiseizure medication called vigabatrin which may be used as an alternative treatment. This medication increases the level of a specific chemical in the central nervous system, helping to control the spasms. However, vigabatrin is known to have side effects including vision problems, drowsiness, irritability, sleep problems, and muscle weakness.
In some cases, a combination of treatments may be more effective than just one. For example, some research suggests that combining vigabatrin with hormonal therapies might work better than hormonal therapies alone.
When treatments like ACTH or vigabatrin aren’t successful, doctors might recommend a special diet known as the ketogenic diet. This is a high-fat, low-carb diet that has been shown to help control seizures in some cases.
If a baby’s spasms are still not controlled with medication or diet, surgery may be considered if there’s a physical abnormality in the brain causing the spasms.
Regardless of the treatment chosen, it’s very important for the doctor to keep monitoring the child for any side effects and to make sure the treatment is working. This can be challenging because there are still many questions about how these treatments work and how best to use them.
What else can Infantile Epileptic Spasms Syndrome (West Syndrome) be?
When a baby shows symptoms like frequent muscle spasms, doctors consider a wide range of possible causes. These could include simple issues like colic (severe pain in the stomach), reflux (when the baby spits up a lot), muscle stiffness, common infant sleep twitching, or excessive startle reflexes. Alternatively, the cause could be more serious conditions such as early infant seizures related to reflexes, brain injury, or severe shaking epilepsies. Please remember that just watching the baby isn’t enough to tell these conditions apart. So, if a baby has symptoms similar to these conditions, doctors should think about infant spasms as a potential cause, even if it might seem like typical baby behavior. If there’s a strong suspicion of infant spasms, further medical tests will be needed.
What to expect with Infantile Epileptic Spasms Syndrome (West Syndrome)
Continued research into infantile spasms – a rare type of seizure experienced by infants – suggests that these have poor long-term outcomes. The mortality rates from these spasms vary from as low as 3% to as high as 33%. Not only are the mortality rates high but up to 60% of patients also continue to have seizures, and many suffer from moderate to severe developmental disabilities after the spasms have stopped.
Infantile spasms that have no identifiable cause (cryptogenic) usually have better outcomes than those that are symptomatic, meaning they have a known cause. The prospects are better for those who are diagnosed and treated quickly, and for those who respond well to a hormone treatment called ACTH. This underlines the importance for doctors to be aware of the signs of infantile spasms, as well as the best strategies for diagnosing and treating them – with this condition, time is critical.
Possible Complications When Diagnosed with Infantile Epileptic Spasms Syndrome (West Syndrome)
Babies with infantile spasms not only run a high risk of developing chronic epilepsy, but they often also struggle with a variety of neurodevelopmental problems. These problems can affect different areas of their development, such as:
- Vision
- Speech
- Hearing
- Writing skills
- Smaller movements (fine motor skills)
- Larger movements (gross motor skills)
- Traits associated with autism
Preventing Infantile Epileptic Spasms Syndrome (West Syndrome)
Once an infant has been diagnosed with infantile spasms, it is crucial that the child’s parents or caregivers are thoroughly educated about the condition. This includes discussing the potential for development delays in the child’s brain, further seizures, and the possibility of serious health risks, potentially including death. Medical professionals and family members should work together to develop a plan for the child’s medical care and for how to address any potential emotional and social impacts.
Providing the family with a wealth of resources, such as fact sheets about the condition, online forums where they can connect with and learn from others who are also dealing with infantile spasms, and information about different treatment options, can be an invaluable way for family members to expand upon the education they receive from their doctor.
