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Infantile spasms

An epileptic spasm is a specific type of seizure seen in an epilepsy syndrome of infancy and childhood often called West Syndrome. These are more commonly called infantile spasms (IS) because they are seen most often in the first year of life, typically between ages 4 and 8 months.

Characteristics include:

  • Epileptic spasms
  • Developmental problems
  • A specific brain wave pattern on electroencephalography (EEG) testing called hypsarrhythmia

The seizures often look like a sudden bending forward of the body with stiffening of the arms and legs lasting for one to two seconds; some children arch their backs as they extend their arms and legs. Spasms tend to happen when the infant wakes up, and often happen in many clusters, with hundreds of seizures per day.

The outlook for children with IS depends mainly on what is causing the spasms. Many babies with IS have neurological impairment before spasms begin, so they are likely to have intellectual challenges (in other words, challenges with learning and thinking). Children may do well if:

  • They receive treatment quickly after the infantile spasms start
  • They develop normally before the spasms start
  • No cause for their spasms can be found

Infantile spasms usually stop by age 4 or 5. But more than half of children who have IS will develop other types of seizures, like Lennox-Gastaut syndrome, an epileptic disorder of later childhood. Children with IS have a higher risk of autism.

Many underlying disorders, such as birth injury, metabolic disorders, and genetic disorders can give rise to IS, making it important to identify the underlying cause. In some children, no cause can be found.

Treating infantile spasms. Getting the seizures to stop and the EEG to improve is the goal of treatment (hypsarrhythmia should stop).

The first-line of treatment uses hormones (like adrenocorticotrophic hormone [ACTH] or prednisolone) or the anti-seizure drug vigabatrin. These treatments are very effective, but they have serious side effects. Parents and caregivers should discuss these treatments with a pediatric neurologist (a doctor who specializes in children's nervous system).

In some children, brain lesions cause the spasms. IS may decrease if these lesions are removed by surgery.

When standard treatments do not improve IS, doctors may suggest other options like the ketogenic diet and anti-seizure drugs.

It is very important for treatment to start as soon as possible. If spams (and hypsarrhythmia) continue, they can have negative effects on the development of a child's brain.

How can I or my loved one help improve care for people with infantile spasms?

Consider participating in a clinical trial so clinicians and scientists can learn more about the IS and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with IS at

Where can I find more information about infantile spasms?

The following organizations and resources help people with IS and their families, friends, and caregivers:

Child Neurology Foundation
Phone: 612-928-6325

Epilepsy Foundation
Phone: 301-459-3700 or 800-332-1000; 866-748-8008 Spanish

National Organization for Rare Disorders (NORD)
Phone: 203-744-0100 or 800-999-6673; 844-259-7178 Spanish

Content source: Accessed June 23, 2023.

The information in this document is for general educational purposes only. It is not intended to substitute for personalized professional advice. Although the information was obtained from sources believed to be reliable, MedLink, its representatives, and the providers of the information do not guarantee its accuracy and disclaim responsibility for adverse consequences resulting from its use. For further information, consult a physician and the organization referred to herein.

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