Infantile Spasms (FAQ)

Answers to questions families often have about caring for their child with infantile spasms

What is an infantile spasm and what causes it?

An infantile spasm (IS) is a specific type of seizure seen in an epilepsy syndrome of infancy and childhood known as West syndrome. West syndrome is characterized by infantile spasms, developmental regression, and a specific pattern on electroencephalography (EEG) testing called hypsarrhythmia (chaotic brain waves). The onset of infantile spasms is usually in the first year of life, typically between 4-8 months. Infantile spasms usually stop by age 5, but may be replaced by other seizure types. Many underlying disorders, such as birth injury, metabolic disorders, and genetic disorders can give rise to spasms, making it important to identify the underlying cause. In some children, no cause can be found. Infantile Spasms (NINDS)

What are the symptoms of infantile spasms?

The seizures primarily consist of a sudden bending forward of the body with stiffening of the arms and legs; some children arch their backs as they extend their arms and legs. Spasms tend to occur upon awakening or after feeding, and often occur in clusters of up to 100 spasms at a time. Infants may have dozens of clusters and several hundred spasms per day.

How are they diagnosed?

Spasms are usually diagnosed by evaluating the clinical circumstances, the presence of developmental delay or regression, and an abnormal EEG—one that shows a particular pattern called "hypsarrhthymia." Additional testing may be performed to look for the underlying cause of the infantile spasms.

What is the prognosis?

The prognosis for children with IS is dependent on the underlying causes of the seizures. The intellectual prognosis for children with IS is generally poor because many babies with IS have neurological impairment prior to the onset of spasms. Spasms usually resolve by mid-childhood, but more than half of the children with IS will develop other types of seizures. IS will sometimes gradually turn into Lennox-Gastaut syndrome, an epileptic disorder of later childhood.

What is the risk for other family members or future babies?

The risk to your family and future babies will depend on the underlying cause for the spasms. Some spasms may have a genetic component and may be possible or likely in future pregnancies. Other spasms may be caused by brain damage; e.g., prenatal stroke.

What treatments/therapies/medications are recommended or available?

Treatment with corticosteroids such as prednisone is standard, although serious side effects can occur. Several newer antiepileptic medications, such as topiramate, may ease some symptoms. Some children have spasms as the result of brain lesions and surgical removal of these lesions may result in improvement.

Is it safer to use vigabatrin or steroids?

The choice of one therapy over another should be made only after a full discussion of benefits and risks with your child's physician. Although both of these treatments have potentially dangerous side effects, the consequences of untreated infantile spasms are often devastating. You might consider joining a support group of parents who have made a similar choice to get a parent perspective. See Epilepsy Foundation Utah Chapter.


Information & Support

Related Portal Content
Infantile Spasms
Assessment and management information for the primary care clinician caring for the child with infantile spasms.
Care Notebook
Medical information in one place with fillable templates to help both families and providers. Choose only the pages needed to keep track of the current health care summary, care team, care plan, health coverage, expenses, scheduling, and legal documents. Available in English and Spanish.

For Parents and Patients

Infantile Spasms (NINDS)
Information about diagnosis, treatment, and current research; National Institute of Neurological Disease and Stroke.

Infantile Spasms (
Several frequently asked questions and answers about infantile spasms.

Patient Education

Let's Talk About... Infantile Spasms (Spanish & English)
Describes what spasms look like and the causes, treatments, and prognosis; Intermountain Healthcare.

Infantile Spasms (Epilepsy Foundation)
Parent focused information on infantile spasms.

Infantile Spasms (American Academy of Neurology) (PDF Document 355 KB)
Information about recognition and treatment of infantile spasms from the American Academy of Neurology

Services for Patients & Families in Ohio (OH)

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* number of provider listings may vary by how states categorize services, whether providers are listed by organization or individual, how services are organized in the state, and other factors; Nationwide (NW) providers are generally limited to web-based services, provider locator services, and organizations that serve children from across the nation.


Infantile Spasms (
Studies looking at better understanding, diagnosing, and treating this condition; from the National Library of Medicine.

Authors & Reviewers

Initial publication: March 2012; last update/revision: September 2016
Current Authors and Reviewers:
Author: Lynne M. Kerr, MD, PhD
Contributing Author: URLEND Trainees, 2011-2012
Funding: The Medical Home Portal thanks the 2011-2012 URLEND Medical Home Portal trainees group for their contribution to this page.