It's very common for newborns and infants to startle. They fling their arms and legs wide, then bring them together. In most cases, this is a normal reflex known as the startle, or Moro, reflex. However, in rare cases, these movements may be a sign of a serious condition called infantile spasms.
Afsaneh Talai, M.D., Pediatric Neurologist at Children's Health℠ and Assistant Professor at UT Southwestern, explains how to tell the difference between normal baby movements and an infantile spasm.
What are infantile spasms?
Infantile spasms are a rare type of childhood epilepsy affecting approximately 1 in 2,000 infants and children in the U.S. each year. The spasms are tiny seizures that can have a big impact on a baby’s development. Infantile spasms most often begin when a baby is 3 to 12 months old.
Infantile spasms can cause serious, permanent changes to a child's developing brain without early diagnosis and treatment. Medication or surgery often stops the spasms, but some children are at risk for other types of seizures later in life. If children are treated quickly and successfully, they are more likely to have healthy development.
What causes infantile spasms?
Different conditions in a baby's brain, such as genetic or metabolic disorders, or brain injury from lack of oxygen or trauma, can cause infantile spasms. Children with conditions such as Down syndrome or tuberous sclerosis have a higher risk for infantile spasms. For approximately 30% of children diagnosed with infantile spasms, there's no identifiable cause.
What do infantile spasms look like?
It's not uncommon for parents to overlook infantile spasms because these tiny seizures can be subtle or look like a normal startle reflex or colic. During an infantile spasm, a baby may stiffen and extend their arms, while scrunching up their knees or bending their neck forward.
"Typically, with infantile spasms, the baby's arms extend out suddenly, and the body may scrunch forward at the waist with the knees drawn up," explains Dr. Talai. "However, infantile spasms can also be mild, and look like just a head bob or the baby's eyes rolling up."
Infantile spasms only last a second or two but often come in a cluster (multiple spasms in a row). Infantile spasms commonly occur around times of sleep, especially upon awakening. After a spasm, babies will often be irritable or cry.
How do I know if it's infantile spasms or a startle reflex?
While infantile spasms can look similar to a normal startle reflex in babies, there are ways to help tell the difference:
- Frequency: Loud noises, bright light or sudden movement can trigger a baby to startle. But unlike that single startle reflex, infantile spasms typically happen back-to-back, or in clusters. Each spasm may last only a second or two, but a cluster can last several minutes.
- Timing of spasms: Infantile spasms often occur when the baby is waking up from sleep, and they will often cry after the spasm.
- Baby's age: The startle reflex is most noticeable in newborns and slowly disappears by 4 to 6 months of age at the latest. Infantile spasms often occur between the ages of 3 to 12 months of age, when the startle reflex has already started to go way.
- Baby's development: The other telltale sign of infantile spasms is a decline in development. For example, you may notice your baby is not doing the same things they used to be able to do or see changes in how your child interacts with you, such as less eye contact or smiling.
What should I do if I think my baby has infantile spasms?
Infantile spasms affect your baby's brain development. Early diagnosis and treatment are critical to stopping the seizures and reducing their impact on your baby's development. If you are concerned your baby may have infantile spasms, follow your instincts. Talk to your baby's pediatrician right away.
You can prepare for the visit and help the doctor with diagnosis by:
- Recording video of a few of the spasms
- Documenting when episodes happen, how long they last and how your baby reacted
- Tracking changes in developmental milestones, such as smiling and interacting
Your child's pediatrician may refer you to a specialist for additional testing if needed.
Designated as a Level 4 Epilepsy Center by the National Association of Epilepsy Centers, Children's Medical Center Dallas provides the highest level of treatment for the most complex cases of pediatric epilepsy, with additional advanced epilepsy treatment options available at our Level 3 Epilepsy Center in Plano. Learn more about our program and services.
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