An infantile spasm is a specific type of seizure that usually occurs in the first year of life. This serious condition can be hard to recognize at first. The baby’s body suddenly bends forward or backwards, then stiffens.

Seizures last only a second or two, usually occurring in clusters.

The incidence of infantile spasms is about 2 to 4 per 10,000 live births. The condition is uncommon. It is not often recognized.

Infantile Spasms Symptoms

An infantile spasm consists of a sudden bending forward of the body, followed by stiffening upward or outward of the arms and legs. Some children arch their backs as they extend their arms and legs.

These seizures can be subtle. They may involve only brief head nods. Or they may be more obvious, involving the head, arms and legs. They last only a second or two. They often occur in clusters.

Some children have dozens of clusters and hundreds of spasms a day. Children may be irritable and cry after a spasm or cluster of spasms.

Recognizing the signs of an infantile spasm is hard because they are so subtle. The seizures look like a normal infant startle reflex or the back arching that is often seen with acid reflux.

Infantile spasms nearly always involve:

  • Seizures as described above.
  • Developmental delays or a loss of previously acquired skills, such as smiling or rolling over.
  • A chaotic pattern of brain waves on an electroencephalogram (EEG).

Early, accurate diagnosis and treatment of infantile spasms leads to a better outcome. However, some children with infantile spasms have long-term developmental disabilities. This is especially true if there is a delay in diagnosis or treatment.

Infantile Spasms Causes

Many infants with infantile spasms have an underlying brain disorder or injury. These can include:

  • An injury caused by lack of oxygen during delivery.
  • An infection (such as meningitis or encephalitis).
  • A metabolic disorder.
  • A genetic disorder. An example is tuberous sclerosis, a rare disease that causes noncancerous tumors to grow throughout the body.
  • A congenital disease. An example is cortical dysplasia, a condition that results from abnormal brain development.

In some children, no cause for infantile spasms can be found.

Diagnosing Infantile Spasms

Finding the cause and diagnosing infantile spasms can be challenging. The process involves:

  • The child’s medical history.
  • A physical and neurologic examination.
  • A video electroencephalogram (EEG).
  • Imaging tests, such as magnetic resonance imaging (MRI).
  • Testing for metabolic and genetic disorders that go along with infantile spasms

Infantile Spasms Treatment

Studies show that the quicker the spasms are controlled, the better the child’s chances for the best developmental outcome. Controlling the spasms is so important that in many cases, treatment begins while doctors work to identify the cause.

Treatment to control infantile spasms seizures can include using:

  • Hormonal therapy, such as adrenocorticotropin (ACTH)
  • A medication called vigabatrin

These therapies can cause side effects. Doctors monitor infants and children closely to identify and treat these side effects in a timely fashion.

Infantile Spasms Prognosis

A child’s outcome depends on the underlying cause of the infantile spasms. If your doctor can find a cause, they can talk about this with you in more detail. Children who were developing normally before the spasms started tend to do better than those who were not.