Infantile Spasms Syndrome (ISS) is a form of epilepsy that appears in infancy, demanding prompt medical intervention. The condition is characterized by subtle but distinct seizures, a chaotic brainwave pattern, and potential impacts on development. Management hinges on early diagnosis and the implementation of specific therapies aimed at stopping the spasms and improving long-term outcomes for the child.
Understanding Infantile Spasms Syndrome
Infantile Spasms Syndrome is defined by a specific type of seizure, known as a spasm, that emerges between three and seven months of age. These spasms are sudden, brief contractions of the body’s muscles, often occurring in clusters, especially upon waking. They can manifest as a “jackknife” movement where the body bends forward, an extension of the limbs and back, or more subtle events like head nods or eye movements.
A key diagnostic feature is an electroencephalogram (EEG) pattern called hypsarrhythmia. When spasms and hypsarrhythmia are paired with a halt or reversal in developmental progress, the condition is termed West Syndrome. The underlying causes of ISS are varied and can include genetic conditions like tuberous sclerosis complex, brain malformations, or brain injury around the time of birth. Without prompt treatment, the ongoing seizures can lead to impairments in cognitive and motor development.
The Diagnostic Journey for Infantile Spasms
The diagnostic journey for ISS begins with caregivers noticing the brief, repetitive movements. Providing a clear history and, if possible, video recordings of the episodes to a physician is an important first step. These observations prompt a clinical evaluation by a neurologist, who will assess the infant’s development and look for signs of an underlying cause.
The primary diagnostic test for ISS is the EEG, which records the brain’s electrical activity. In infants with ISS, the EEG reveals a chaotic and disorganized pattern known as hypsarrhythmia between spasm clusters, which confirms the diagnosis. Once ISS is confirmed, further tests such as an MRI of the brain, along with blood and urine analyses, are often performed to identify the specific cause of the spasms, which can help guide treatment decisions.
Primary Medical Treatments for ISS
Primary medical therapies for ISS involve hormonal treatments and a specific anti-seizure medication. Adrenocorticotropic hormone (ACTH) is a hormonal therapy given by injection into a muscle. It is thought to work by reducing the levels of corticotropin-releasing hormone (CRH) in the brain, but it requires careful monitoring for side effects like high blood pressure, irritability, and increased risk of infection.
Oral corticosteroids, such as prednisolone, are another form of hormonal therapy used as a first-line treatment. Given by mouth, high-dose prednisolone works similarly to ACTH and also carries risks that require management, including masking signs of infection. For infants whose spasms are caused by tuberous sclerosis complex (TSC), the medication vigabatrin is the recommended first-line therapy.
Vigabatrin is an anti-seizure medication that works by increasing the concentration of a calming neurotransmitter, GABA, in the brain. A potential side effect is permanent damage to peripheral vision, which necessitates regular ophthalmologic screening during treatment. In some cases, a combination of hormonal therapy and vigabatrin may be used from the outset to improve the chances of stopping the spasms quickly.
Other Therapeutic Strategies for ISS
When first-line treatments are not effective or are unsuitable, other therapeutic avenues are explored. The ketogenic diet, a medically supervised high-fat, low-carbohydrate diet, has been used to treat various forms of epilepsy, including ISS. It can be effective for infants with intractable spasms who did not respond to initial drug therapies, as the diet is thought to alter brain metabolism to reduce seizure susceptibility.
Other anti-seizure drugs may be considered as second-line options, such as topiramate, zonisamide, or valproic acid, though their effectiveness can vary among patients. For a small subset of infants, the spasms are caused by a specific, identifiable lesion or malformation in the brain. In these cases, epilepsy surgery to remove the affected brain tissue can be a curative option and is considered early if a clear focal cause is found.
Research into other potential treatments is ongoing, exploring compounds like cannabidiol or mTOR inhibitors for specific underlying causes.
Life Beyond Infantile Spasms Treatment
The long-term outlook for a child after treatment for infantile spasms is variable and depends on the underlying cause of the syndrome and how quickly the spasms were controlled. Even after spasms cease, many children face ongoing developmental challenges affecting their cognitive, motor, and behavioral skills. A comprehensive and early start to intervention services is a large part of post-spasm management.
These services often include physical, occupational, and speech therapy to support the child in reaching their full potential. There is also a risk for children who have had ISS to develop other types of seizures later in life, such as those associated with Lennox-Gastaut Syndrome. This necessitates long-term follow-up with a neurologist to monitor for any new seizure activity and manage overall neurological health. For families, connecting with support organizations can provide emotional and practical guidance.