Infantile Spasms

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  • See also

    Adrenal crisis/insufficiency

    Key points

    1. Infantile spasms (IS) are a type of seizure, and are the most common severe epilepsy in infants
    2. IS are typically sudden, brief, bilateral and symmetric contraction of the muscles of the neck, trunk and extremities, occurring in clusters
    3. IS are often the presenting feature of a significant underlying neurological disorder
    4. Prompt diagnosis and treatment are critical to minimise the developmental impacts
    5. First-line treatment is usually high dose prednisolone
    6. High dose prednisolone may mask responses to infection, including fever. Signs of sepsis in a child on high dose prednisolone should be managed as per the S­­epsis CPG


    • Peak age of IS onset is 3 to 7 months
    • IS typically occur in the context of West syndrome (WS), characterised by the triad of IS, hypsarrhythmia on EEG and developmental arrest/regression.
    • Not all children with IS have all features of WS
    • Common causes of IS include tuberous sclerosis complex (TS), trisomy 21, focal structural abnormality, perinatal HIE
    • IS are associated with developmental delay in over 80% of infants, and high rates of ongoing epilepsy
    • Prompt treatment is required to minimise the adverse developmental impact. High dose prednisolone is first-line treatment for most infants; vigabatrin is first-line in infants with TSC


    1. Are the infant’s episodes IS?
    Features suggestive of IS

    • Occur in clusters, most commonly shortly after waking from sleep
    • Typically sudden flexor or extensor spasms of the whole body
    • May be more subtle - head nodding or facial or eye movements
    • May be asymmetric
    • Review parental video recordings of the episodes if available

    Differential diagnosis:

    • Non-epileptic episodes such as shuddering and benign myoclonus of infancy
    • Benign myoclonic epilepsy of infancy
    • Other infantile epilepsies

    2. What is the underlying cause for IS?
    Features that provide potential clues to the underlying cause

    • Pre-existing condition known to be associated with IS (eg TSC, trisomy 21)
    • Family history of seizure disorder or developmental delay (genetic basis)
    • Early handedness (focal structural abnormality)
    • Dysmorphic features or congenital anomalies (chromosomal abnormality)
    • Skin lesions (eg hypopigmented macules of TSC)
    • Pre-existing developmental delay
    • Neonatal or early infantile seizures
    • Head circumference growth


    • Neurological consultation is mandatory for children with suspected IS
    • Admission is recommended for confirmation of IS with EEG, investigation of aetiology, and commencement of treatment


    • Urgent awake and sleep EEG
    • Prompt MRI brain
    • Other investigations for underlying aetiology (if unknown), including chromosomal microarray, urine metabolic screen and consideration of other genetic testing


    Neurology team should determine appropriate treatment

    • High dose prednisolone is first-line treatment (except for TS and treatable metabolic conditions)
    • Prednisolone 10 mg QID for 1 week then:
      • If spasms cease during this week, continue 10 mg QID for 1 more week, then wean off 10 mg every 5 days (ie TDS to BD to once daily then cease) for a total 4 weeks treatment
      • If spasms continue after week 1 of treatment, the prednisolone dose should be increased to 20 mg TDS for 1 week (then wean to 10 mg QID, then BD to once daily and then cease)
      • Vigabatrin is second-line treatment after 2 weeks of inadequate response to corticosteroids, and should be added to the weaning prednisolone regimen.
    • Vigabatrin is recommended as first line treatment in TSC
    • First-line treatment with combination prednisolone and vigabatrin has a higher rate of spasm cessation but showed no improvement in developmental outcome at age 18 months over prednisolone alone. Also, vigabatrin is associated with potential ocular and neurologic side effects. Thus, it has not superseded prednisolone monotherapy as standard practice, although may be considered on a case-by-case basis

    Precautions and monitoring while taking prednisolone:

    • High dose prednisolone treatment is associated with increased risk of serious +/or opportunistic infections
      • Any child with IS on prednisolone who presents febrile or unwell should be admitted and managed as per the Sepsis Guideline. Consider infectious disease consultation
      • If there is vomiting or significant diarrhoea, administer IV/IM hydrocortisone
    • Prophylactic trimethoprim-sulfamethoxazole for infection prevention
    • Monitor BP, blood glucose and weight twice weekly
    • Vaccines should be delayed until one month after ceasing prednisolone. See Victorian Immunisation Handbook

    Consider consultation with local paediatric team when

    All children with suspected IS

    Consider transfer when

    • Urgent EEG, prompt MRI and neurology consultation are unavailable
    • Consider transfer of unwell child if requiring care beyond the comfort level of the hospital

    For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services.

    Consider discharge when

    • Child has follow-up arranged with neurologist, or paediatrician with input from a neurologist, and a follow-up EEG booked (after two weeks).
    • Admission for IS diagnosis and initial management is usually brief, and discharge is not dependent on spasm cessation

    The Steroid Alert Card should be given to parents prior to hospital discharge regarding treatment in the event of becoming unwell or febrile

    Parent information sheet

    Last Updated May 2020

  • Reference List

    1. Darke K, Edwards SW, Hancock E, Johnson AL, Kennedy CR, Lux AL, Newton RW, O'Callaghan FJ, Verity CM, Osborne JP. Developmental and epilepsy outcomes at age 4 years in the UKISS trial comparing hormonal treatments to vigabatrin for infantile spasms: a multi-centre randomised trial. Arch Dis Child 2010;95:382-6.
    2. Go CY, Mackay MT, Weiss SK, Stephens D, Adams-Webber T, Ashwal S, Snead OC 3rd; Child Neurology Society; American Academy of Neurology. Evidence-based guideline update: medical treatment of infantile spasms. Report of the Guideline Development Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology. 2012 Jun 12; 78(24):1974-80.
    3. Lux AL, Edwards SW, Hancock E, Johnson AL, Kennedy CR, Newton RW, O'Callaghan FJK, Verity CM, Osborne JP. The United Kingdom Infantile Spasms Study comparing vigabatrin with prednisolone or tetracosactide at 14 days: a multicentre, randomised controlled trial. Lancet 2004;364(9447):1773-1778.
    4. O'Callaghan FJ, Edwards SW, Alber FD, Hancock E, Johnson AL, Kennedy CR, Likeman M, Lux AL, Mackay M, Mallick AA, Newton RW, Nolan M, Pressler R, Rating D, Schmitt B, Verity CM, Osborne JP. Safety and effectiveness of hormonal treatment versus hormonal treatment with vigabatrin for infantile spasms (ICISS): a randomised, multicentre, open-label trial. Lancet Neurol 2017; 16(1):33-42.