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Infantile Spasms


A 5-month-old infant presents to the Paediatric ED.

His parents have noticed that he has been making funny movements’ over the last few weeks.

He has also seemed a bit more withdrawn and miserable.

“Could it be colic? Or reflux?” they ask.

This is a fairly common presentation with small babies. Determining what parents mean by ‘funny movements’ can be hard. A good history with video evidence is crucial as infantile spasms, although rare, need same-day assessment and treatment and should not be missed.

What are Infantile Spasms?

Infantile Spasms are a type of epilepsy which usually occurs in children under one, although they can present any time from a month onwards until the age of two. It is associated with a chaotic EEG pattern characterised by hypsarrhythmia and significant neurological damage if the spasms are uncontrolled.

EEG in infantile spasms
Compare the normal EEG with the chaotic hypsarrhthmia

Parents/carers often describe abnormal movements with ‘head drops’, ‘crunches’, ‘shoulder drops’ or ‘eye rolls’. The spasms can be fairly subtle and are often confused with reflux or normal baby movements. Parents may also note that their baby has delayed, slowing or regression of development or behavioural changes such as changes in mood or sleep patterns.

Generally, spasms increase in frequency over time and occur in clusters. They are usually symmetrical and associated with sleep transitions and feeding. Babies cannot be distracted during the episode.

It is well worth looking at videos of spasms to familiarise yourself with the potential presentation – look at the awareness video at the end of this blog.

Some infants with Infantile Spasms will have known an underlying condition such as hypoxic ischaemic encephalopathy, Downs Syndrome or Tuberous Sclerosis. They may also already have other seizure types and be under paediatric services. However, a proportion may have had a normal pregnancy and/or development before presentation.

How are Infantile Spasms diagnosed?

If there is a suspicion of Infantile Spasms, regardless of the presence or absence of an underlying condition, the baby needs to be referred that day to a Paediatric Neurologist or Paediatrician with a special interest in epilepsy. An urgent EEG should be arranged. NICE guidance has recently been updated to that effect.

Infantile spasms syndrome
Specialist involvement

If a child under two years has suspected or confirmed infantile spasms, within 24 hours, seek guidance from, and refer the child urgently to, a tertiary paediatric neurologist to ensure rapid assessment, including a sleep electroencephalogram (EEG), and rapid treatment to stop spasms.

Other tests should be conducted to determine potential underlying causes, such as a metabolic screen, genetic testing, MRI, and lumbar puncture.

Diagnosis is made based on the history, evidence of spasms and EEG findings. Not all EEGs are immediately abnormal, and if there is a strong suspicion of spasms, children need a sleep-provoked or 24h EEG.

What treatments are available for infantile spasms?

Prompt treatment is key and a matter of priority. Most children should be immediately started on high-dose steroids (prednisolone or ACTH) and vigabatrin. The ICISS study in 2017 showed dual therapy to be more effective at stopping spasms than steroids or Vigabatrin alone.

During steroid treatment, infants are at risk of significant side effects and will need regular blood pressure and glucose monitoring. They are also at risk of adrenal insufficiency during the steroid wean.

Treatment aims to stop the spasms as quickly as possible, ideally within the first two weeks. If this happens, the EEG is repeated, and medication can be weaned. Depending on the response, steroids are generally weaned after 2-4 weeks. Vigabatrin is weaned over a longer period but generally before six months due to the potential risk of peripheral vision loss. Maintenance therapy is sometimes required in patients with higher seizure risks.

If first-line treatment is unsuccessful, other options include a ketogenic diet, other anti-epileptic drugs or epilepsy surgery if there is a specific brain area to target.

Relapse of spasms occurs in about one-third of patients and will require further intervention. This may include repeated steroid courses.

What is the prognosis of infantile spasms?

An underlying cause will be known or found in about 75% of cases; there are at least 200 associated conditions, including genetic, metabolic and structural brain diseases. About one-quarter of cases are deemed idiopathic and have a better prognosis.

Outcomes are extremely variable, dependent on the cause, and include developmental delays, neurodivergence, or behavioural issues. About 60% of infants develop other seizure types, including resistant epilepsy and Lennox Gastaut Syndrome. If treated promptly, a smaller group of children can fully recover without any developmental effects.

Children with ongoing seizures or developmental delays will likely need ongoing support from various services. These might include neurology follow-up, community paediatrics, occupational therapy, physiotherapy, portage, specialist education etc.

The paediatric SHO on call reviewed the video evidence that the parents had taken of the baby’s episodes and took a thorough history.

She immediately alerted the Consultant on site, who had a special interest in epilepsy.

Subsequently, the baby was admitted, and an EEG performed the next morning confirmed a diagnosis of Infantile Spasms.

Prompt treatment was initiated on the same day.

Infantile Spasms Awareness Video

Take Home Messages

A diagnosis of Infantile Spasms is rare but should not be missed. Same-day referral for specialist assessment and an urgent EEG is essential. Rapid diagnosis and treatment will maximise positive outcomes, regardless of the underlying cause.

Encourage parents to obtain as much video evidence as possible.

Children have a huge range of potential prognoses, and with prompt intervention, a minority will make a full recovery


6 Treating childhood-onset epilepsies | Epilepsies in children, young people and adults | Guidance | NICE

Safety and effectiveness of hormonal treatment versus hormonal treatment with vigabatrin for infantile spasms (ICISS): a randomised, multicentre, open-label trial – The Lancet Neurology

UK Infantile Spasms Trust



  • Alice Goldhill is a GP Partner at a big practice in Kent. Her youngest child had Infantile Spasms as a baby, and she has been a Trustee of the UK Infantile Spasms Trust since 2020. She drinks copious amounts of tea, and occasionally escapes from her work/3 kids by undertaking long distance runs.



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