Infantile Spasms: Causes, Symptoms, Diagnosis And Treatment

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Infantile spasms (IS), also called West Syndrome, is a type of epilepsy in babies. This may look like stiffening of muscles or a startle. Although rare, it is a severe brain disorder or epileptic encephalopathy, which damages the brain. Babies who develop infantile spasms show symptoms by four to six months (1). The condition may occur in babies with or without known brain abnormalities or injuries. Early diagnosis and management may help improve the outcomes.

Read on to know the signs, symptoms, causes, diagnosis, complications, and treatment options of infantile spasms.

Signs And Symptoms Of Infantile Spasms

You may notice quick body jerks in your baby, along with extended arms and dropped heads. Babies may have clusters of seizure episodes lasting one to two seconds each, and spasms may recur in five- to ten-second gaps.

These are often confused with reflux, colic, or sleep jerk until the spasms are frequent and severe. The seizure may occur after the baby wakes up from sleep and is not usually seen during sleep.

Other signs and symptoms of infantile spasms may include (1):

  • Sudden stiffening of the body during the spasm
  • Arching of the back
  • Jackknife position, that is, when the head, legs, and arms bend forward
  • Tummy crunch
  • Rolling eyes
  • Blinking wide eyes
  • Not smiling or appearing unhappy
  • Reduced interactions
  • Irritable
  • Inconsolable
  • Startled look

These symptoms are also seen in other diseases. An infantile spasm is a seizure with significant complications. Therefore, seek prompt medical care if your baby has any signs and symptoms that seem like IS.

Causes Of Infantile Spasms

The exact cause may not be identified in many babies with infantile spasms. Genetic factors are the most common causes. The following factors may also cause infantile spasms (2).

  • Brain malformations
  • Infections, such as meningitis and encephalitis
  • Brain trauma or injury
  • Anomalies of blood vessels in the brain
  • Metabolic disorders
  • Genetic disorders, such as Down syndrome
  • Tuberous sclerosis with brain involvement
  • Cerebral palsy
  • Vitamin B6 deficiency

The exact cause may not be identified in all babies with infantile spasms. Any brain abnormalities affecting the brain’s electrical activity could result in infantile spasms. If the baby has infections, metabolic disorders, or genetic disorders, seek early medical care to reduce the risk of seizures.

Diagnosis Of Infantile Spasms

Pediatricians may refer your baby to a pediatric neurologist for a detailed evaluation of the infantile spasms. A pediatric neurologist specializes in neurological problems in children.

The following tests are often performed to confirm the diagnosis (3).

  • Blood tests help identify infection and inflammatory markers, metabolic disorders, and genetic disorders.
  • Urinalysis can also give some information about the baby’s health.
  • Electroencephalography (EEG) records the brain’s electrical activity, and the doctor can find changes in electrical waves of the brain. Hypsarrhythmia, an abnormal brain wave pattern, is a characteristic EEG finding in infantile spasms.
  • Video electroencephalography (VEEG) is an EEG recording along with the video of the baby. This may help determine the brain activity along with the spasms.
  • Imaging tests such as CAT scan (CT), MRI, and PET scans help visualize the brain abnormalities.

Genetic counseling and testing are often suggested if genetic conditions are suspected. The tests may vary depending on the causative factors. 

Treatment Of Infantile Spasms 

Early interventions may give favorable outcomes, such as less brain damage. Treatment options are chosen based on the underlying causes (4).

  • Hormonal therapy with adrenocorticotropic hormone (ACTH)
  • Anti-seizure medications, such as vigabatrin
  • Steroids, such as prednisolone
  • Some babies may benefit from a ketogenic diet

Vaccinations are delayed for a month after stopping prednisolone therapy (5).

The American Academy of Neurology and the Child Neurology Society recommend ACTH shots as initial medication. This treatment is usually given for six weeks, and most babies have complete cessation of spasms and improved EEG results after the course of treatment. Vaccinations are delayed for a month after stopping prednisolone therapy (5)

Possible Complications Of Infantile Spasms

The following complications may occur in babies with IS (6).

  • Cognitive impairment
  • Developmental delays or even regression
  • Learning difficulties
  • Loss of smile
  • Problems with social interaction

Complications due to permanent brain damage can be reduced or avoided through early treatment.  Babies may require follow-ups and medications for a longer duration to reduce the risk of complications. Doctors may also conduct developmental tests and suggest therapies if there are any developmental delays.

Prognosis Of Infantile Spasms

The outcome may vary depending on the underlying cause. If the reasons are modifiable with treatment, it is possible to control the spasms. Early initiation of treatment may have positive outcomes. However, most babies with infantile spasms may have poor intellectual prognosis since the neurological damage may occur before the onset of spasms.

Babies with infantile spasms may have an increased risk of developing epileptic disorders, such as Lennox-Gastaut syndrome, in their later childhood. There is also a higher risk of autism spectrum disorder (7).

Frequently Asked Questions

1. Can a baby with infantile spasms live a normal life?

Yes, studies suggest that infants with treatable etiologies associated with infantile spasms can lead a normal life with timely interventions (8).

2. What is the difference between infantile spasms and seizures?

Infantile spasms (a type of seizure) usually occur in an awakened state and last for a few seconds. In contrast, other seizures may last anywhere from 30 seconds to two minutes (9).

3. Are infantile spasms painful?

Usually, infantile spasms may not cause pain. However, these spasms may sometimes be mistaken for colic or reflux (which may cause pain sensations) (10). It is better to consult the doctor in case of doubts for clarity.

If you feel your child is experiencing infantile spasms, it needs immediate medical attention. Since these spasms don’t last for very long, you can shoot a video while they are experiencing it for the doctor to see and diagnose. It may be scary for you to see your child experiencing these spasms, but maintaining your composure can help you think fast and utilize your presence of mind. Prompt treatment is pivotal in preventing permanent or irreversible brain damage. Your doctor will weigh the risks versus benefits before designing your infant’s treatment plan.

Key Pointers

  • Infantile spasms are a type of seizure that results in sudden stiffening of the body.
  • An arched back, rolling eyes, and a startled look are common symptoms of an infantile spasm.
  • Such spasms may be caused by cerebral palsy, brain malformations, or certain infections.
  • Hormonal therapy, anti-seizure medications, and other treatment options are discussed as you scroll through.


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Dr. Wayne Hough

(MBChB, MMed, FC Paeds)
Dr. Wayne Hough is a pediatrician currently based in the Northern Suburbs of Cape Town in South Africa. He got his medical degree from the University of Stellenbosch. He then worked at the Tygerberg Children's Hospital before completing his pediatric training and qualification from the South African College of Medicine. Dr. Hough also holds a MMed degree in pediatrics from... more

Dr Bisny T. Joseph

Dr. Bisny T. Joseph is a Georgian Board-certified physician. She has completed her professional graduate degree as a medical doctor from Tbilisi State Medical University, Georgia. She has 3+ years of experience in various sectors of medical affairs as a physician, medical reviewer, medical writer, health coach, and Q&A expert. Her interest in digital medical education and patient education made... more