Merck Manual

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Infantile Spasms

(Salaam Seizures)


M. Cristina Victorio

, MD, Northeast Ohio Medical University

Last full review/revision Mar 2020| Content last modified Mar 2020
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In infantile spasms, children suddenly raise and bend their arms, bend their neck and upper body forward, and straighten their legs.

  • The spasms are usually caused by serious brain disorders.

  • Many children who have infantile spasms also develop abnormally or have intellectual disability.

  • Electroencephalography is done to diagnose the disorder, and analysis of samples of blood, urine, and the fluid around the spinal cord as well as brain imaging help doctors identify the cause.

  • Injecting adrenocorticotropic hormone into a muscle or giving a corticosteroid or vigabatrin (an antiseizure drug) by mouth often helps control the spasms.

Infantile spasms are a type of seizure. A seizure is an abnormal, unregulated electrical discharge that occurs within the brain and temporarily interrupts normal brain function.

Infantile spasms last for only a few seconds but typically occur close together in a series that lasts several minutes. Children may have many series of spasms a day. Spasms usually start when children are younger than 1 year of age. They may stop by 5 years of age, but often, another type of seizure then develops.


Usually, infantile spasms occur in infants who have a serious brain disorder or developmental problem, which may have already been diagnosed. These disorders include

Tuberous sclerosis complex, a hereditary disorder, is a relatively common cause of infantile spasms. People with this disorder have long, narrow growths in the brain, which resemble roots or tubers.

Sometimes no cause of infantile spasms can be identified.


Spasms usually consist of a sudden jerk (spasm) of the trunk and limbs that looks very much like the infant has startled. Sometimes the spasms involve only slight nodding of the head. Spasms may last several seconds, and children usually have many spasms in clusters, one right after the other.

Spasms typically occur soon after children wake up and occasionally occur during sleep.

In most affected children, intellectual development, including development of language skills, is slow, and intellectual disability is present. When infantile spasms start, children may at least temporarily stop smiling or lose developmental skills that they have learned, such as being able to sit up or roll over.


  • Electroencephalography

  • Magnetic resonance imaging,

  • Sometimes blood and urine tests and a spinal tap

Doctors diagnose infantile spasms based on symptoms and results of electroencephalography (EEG), which is done to check for specific patterns of abnormal electrical activity in the brain. EEG is done while children are sleeping and while they are awake.

Magnetic resonance imaging (MRI) of the brain is done to look for signs of brain damage or malformations.

Other tests are done to look for the cause:

  • Samples of blood, urine, and the fluid around the spinal cord (cerebrospinal fluid) may be analyzed to check for disorders that may be causing the spasms, such as metabolic disorders. Cerebrospinal fluid is obtained by doing a spinal tap (lumbar puncture).

If the cause of infantile spasms is still unclear, genetic tests may be done.


  • Adrenocorticotropic hormone

  • A corticosteroid

  • Vigabatrin (an antiseizure drug)

Because early control of infantile spasms is associated with a better developmental outcome, early identification and treatment of spasms are essential.

The most effective treatment for infantile spasms is adrenocorticotropic hormone (ACTH), injected into a muscle once a day. ACTH therapy is typically continued for 2 to 3 weeks and then tapered off over 6 to 9 weeks. A corticosteroid (such as prednisone), given by mouth, may also be effective as an alternative to ACTH.

The only other drug that has been clearly proved to help stop the spasms is the antiseizure drug vigabatrin given by mouth. It is particularly helpful when tuberous sclerosis complex is the cause. There is not enough evidence to support that any other antiseizure drug or a ketogenic diet is effective.

Sometimes epilepsy surgery is done to eliminate the cause of the spasms. An area of the brain may be surgically removed if seizures are caused by only that one area and that area can be removed without significantly affecting the child's ability to function.

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