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Infantile Spasms

Reviewed by: Amy W. Anzilotti, MD
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What Are Infantile Spasms?

Infantile spasms is a seizure disorder in babies. The seizures (or spasms) make muscles in the arms and legs stiff and bend the baby's head forward. They look very much like a startle.

Babies with the condition also might have slowed development or loss of skills (like babbling, sitting, or crawling). The spasms usually go away by age 4, but many children go on to have other kinds of epilepsy later in life.

What Do Infantile Spasms Look Like?

Spasms start suddenly and last a second or two. They often come one after another in a cluster that lasts several minutes. They happen most often just after waking. They're often mistaken for colic, reflux, or hiccupping.

A baby having a spasm might have:

  • the head bent forward with arms flung out and the knees pulled into the body (described as "jackknife")
  • the head bent back with the arms and legs straightened
  • small movements in the neck or other parts of the body

What Causes Infantile Spasms?

Infantile spasms (also called West syndrome) can be caused by problems with the way the brain developed in the womb, infections, brain injury, or abnormal blood vessels in the brain (such as an arteriovenous malformations). Infantile spasms also can happen in babies with some types of metabolic and genetic disorders. In rare cases, a baby's infantile spasms are caused by vitamin B6 deficiency.

More and more gene mutations are being linked to infantile spasms. Sometimes, the cause isn't known.

How Are Infantile Spasms Diagnosed?

Infantile spasms are diagnosed by a pediatric neurologist (a doctor who treats brain, spine and nervous system problems). Testing may include:

  • blood tests and urine tests (to look for infections or illnesses)
  • EEG to see brain waves/electrical activity in the brain. A particular EEG finding called "hypsarrhythmia" often confirms the diagnosis, but not every child with infantile spasms will have this.
  • VEEG, or video electroencephalography (EEG with video recording)
  • CAT scan, MRI, and PET/MRI scans to look inside the brain

How Are Infantile Spasms Treated?

Infantile spasms usually are treated with seizure medicines or steroids. If medicines don't control the spasms, a special diet, such as the ketogenic diet, might help. Sometimes, doctors may recommend surgery.

How Can I Help My Child?

To help your child, follow the doctor's instructions to:

  • Give any medicines as prescribed.
  • Go for developmental assessments and therapies.
  • Go to all follow-up medical visits.
Reviewed by: Amy W. Anzilotti, MD
Date reviewed: February 2021