Jerks, Startle, Infantile spasm, West syndrome- How to diagnose

Jerks, Startle, Infantile spasm, West syndrome- How to diagnose

Jerk in children is due to multiple causes. However, not all jerks are worrisome. Jerk in infants less than be epileptic (due to seizures) or non-epileptic (not due to seizures).


If you are wondering, what these 4 terms are, these are term of seizures and epilepsy in children. What happens in this type of jerks or jhatka or chaukna, is that there is there is bending of heads and arms towards his knees, and then immediate relaxation of the body into the upright position … these bowings and relaxing would be repeated alternately at intervals of a few seconds, and repeated from 10 to 20 or more times at each attack, which attack would not continue more than 2 or 3 minutes; There could be sometimes 2, or more attacks in the day.‘ They’re often mistaken for colic, reflux, or hiccupping.

West syndrome has three components, although diagnosis can still be made in the absence of one:

  • Infantile spasms.
  • Hypsarrhythmia (classical very abnormal electroencephalograph (EEG) that occurs even between attacks).
  • Development delay

So infantile spasm is part of West syndrome

Infantile spasm usually starts between 4 and 7 months of age, with 90% starting under 1 year of age. This seizure type is predominantly seen in infants and small children.

Spasms or jerks begin with a sudden, rapid, tight contraction of the chest, abdomen, neck and hands, with gradual relaxation after 0.5 to 2 seconds. Tightening can last 5 or 10 seconds. They may vary from gentle nodding of head or head jerk to a powerful movement of the whole body

  • These jerks occur in clusters (2-100 times in a short time). There may be lapse of 5 to 30 seconds between each jerk or spasm. These jerks occur just before sleep or on awaking. Jerks can occur in sleep but this is uncommon
  • Spasms can be flexor (forward bending), extensor (backward bending), or a mixture of both.

Between 70% and 90% have development delay or loss of development skills. Physical examination is usually normal, although in some children may have adenoma sebaceum of tuberous sclerosis.

  • Examination with Wood’s lamp is often helpful to see the hypopigmented skin lesions of this condition.
  • Mild to moderate growth restriction is common.
  • Neurological examination reveals nothing specific. Children usually have certain tone abnormality like hypotonia of hypertonia due to brain damage
  • Ophthalmic examination may reveal evidence of one of the syndromes associated with the condition.

Jerks can be due to start, fear, sleep myoclonus, clonic seizures or infantile spasms. A good child specialist and neurologist can easily diagnose these conditions.

Causes of infantile spasm can be divided into symptomatic or idiopathic.


Any disease that can cause brain damage can cause infantile spasms

  • Prenatal conditions
    • Hydrocephalus, microcephaly, Sturge-Weber syndrome, tuberous sclerosis
    • genetic syndromes (such as Aicardi’s syndrome and Down’s syndrome)
    • hypoxic or ischaemic brain damage, HIE, congenital infections, and trauma.
  • Perinatal disorders
    • Hypoxia or ischaemia of the brain, HIE, birth asphyxia, Hypoxic Ischemic encephalopathy
    • Meningitis, new born brain infections, septicaemia
    • Encephalitis
    • Trauma
    • Intracranial haemorrhage.
    • Low sugar, hypoglycaemia
    • Very high bilirubin, bilirubin encephalopathy, kernicterus,
    • Polycythaemia,
  • Postnatal disorders include pyridoxine dependency, maple syrup urine disease, phenylketonuria, meningitis, degenerative diseases, biotinidase deficiency, and trauma.


Idiopathic infantile spasms are diagnosed if there is abnormal or delayed development before the onset of jerks, no underlying disorders or definite presumptive causes are present and no neurological or neuroradiological abnormalities exist. MRI brain in such children is normal. ‘idiopathic’ and ‘cryptogenic’ are similar terms. More and more gene mutations are being associated with infantile spasms. Infantile spasm can also happen in children with metabolic and genetic disorders. In rare cases, a child’s infantile spasms are caused by vitamin B6 deficiency, biotinidase deficiency. These disorders respond rapidly to treatment

  • Brain MRI (preferably 3 tesla) has the highest diagnostic efficiency in determining the cause of infantile spasms
  • Blood tests include complete blood counts, liver function test, renal function, glucose, ionised calcium, magnesium and phosphate are to be done in all children with seizures, spasm and jerks
  • Blood cultures, urine examination and cerebrospinal fluid analysis if infection is suspected.
  • Urine amino acids and organic acids (TMS and GCMS) and serum biotinidase are done if MRI is normal and there is no risk factor complicating child birth
  • EEG has to be done in all children with jerks, spasms, seizures, as hypsarrhythmia is crucial to the diagnosis:
    • A prolonged sleep EEG study with waking and sleeping record is needed
    • Hypsarrhythmia is a typical EEG interictal pattern consisting of chaotic, high to extremely high-voltage polymorphic rhythms with multifocal spikes and wave discharges.
    • Multiple types of this variations of this Hypsarrhythmia pattern are seen
    • The EEG ictal pattern has 11 different types

There is no correlation between the EEG patterns and the type of jerks and spasms

Other tests include Visual evoked potentials VEP test and Brain stem evoked potentials like BERA test

Opthal vision and hearing assessment

Physical assessment for need of physiotherapy

Dietary assessment

GER scan for children having recurrent choking, vomiting and regurgitation of feed

Treatment is aimed at controlling seizures, with the least side-effects and the best quality of life. Adrenocorticotropic hormone (ACTH), prednisolone and vigabatrin are the three best first-line medications for treatment of infantile spasms

Several other seizure drugs (levetiracetam, nitrazepam, sodium valproate, topiramate, zonisamide) are used when the first three medications fail. These seizure medications as used as add-on or adjunctive treatment in refractory cases. Pyridoxine (or pyridoxal phosphate) and the ketogenic diet are also treatment options in selective refractory cases

First-line of treatment

  • ACTH: this is effective in about 50-65% of cases. Effectiveness is high if MRI brain is normal. It involves a daily intramuscular (IM) injection in thigh for 2-3 months. The monthly cost for 10 kg child ranges between 8000-10000 Rs for injection plus the cost of administration. Read more on precautions
  • Prednisolone may be useful instead of ACTH due to its low cost, ease of use, and increasing evidence that it may be similar in efficacy to ACTH and vigabatrin. The only advantage of oral prednisolone is monthly cost of maximum Rs 500. oral prednisolone is preferred in rural areas where child specialist may not be available for intramuscular injection of ACTH. Read more on precautions
  • Vigabatrin has a success rate of about 50%; Vigabatrin is first choice medicine in jerks due to tuberous sclerosis. Visual field defects need to be monitored 3 monthly after vigabatrin therapy. Latest evidence also suggests possible benefit with combined ACTH and Vigabatrin use in Europe/ United Kingdom. In general, the long-term results between treatment with steroids (ACTH) and vigabatrin in terms of control, outcome and severe side-effects are similar
  • Common side effects to keep in mind during Vigabatrin treatment

    Gastrointestinal: Constipation (infants: 12%-14%) diarrhea (10%-12%), vomiting (infants: 15-12%)

    Nervous system: drowsiness (infants: 17-45%; children/ adolescents: 6%), insomnia (infants: 10-12 %), irritability (infants: 16-23%), sedated state (infants: 17-19%)

    Ophthalmic: Blurred vision (13%), nystagmus disorder (adults: 13%), visual field loss (adults: ≥30%)

    Fever (infants: 19-29%)

    Vision should be assessed to the extent possible at baseline (no later than 4 weeks after initiation), at least every 3 months during therapy and at 3 to 6 months after discontinuation.

Second-line treatment
This includes:

  • Benzodiazepines, valproate, lamotrigine, topiramate or zonisamide.
  • In a few patients, epilepsy surgery like resection of part of the brain can give relief, especially in tuberous sclerosis.
  • A ketogenic diet is tried in refractory cases.

This very much depends on aetiology or cause of seizures. Neurodevelopmental outcome is usually bad in children with occipital gliosis, hypoglycaemic brain injury, HIE, PVL, cystic encephalomalacia. The outcome depends on whether how well the spasms respond. The prognosis for idiopathic infantile spasms with normal MRI is better than for those infantile spasms with abnormal MRI.

Early identification and early initiation of treatment shows better neurodevelopmental outcomes. The outcome of infantile spasms in children with Down’s syndrome and neurofibromatosis type I, is relatively better. The spasms usually go away by the time a child is 4 years old, many children with infantile spasms will have other kinds of seizures later in life, and a 100% cure might be difficult in children with children with abnormal MRI.

Neurologist- 1-2 times a month for seizure assessment, diet nutrition, development assessment

Physiotherapy- 2-4/ month

Eye specialist- 3 monthly. 1 monthly for steroid side effect assessment

Speech Therapy and Occupation therapy- 2-4 per month

Blood test- as prescribed. In general, 6 monthly

Vaccination- Skip or stop till 3 months after stopping steroids


Growth and nutrition


EYE problems like squint and low vision

Hearing and speech problems

Physical problems like tightness, poor head control, poor trunk control, toe walking, scissoring

15 Additional Links for Reading on Infantile Spasm, Hypsarrhythmia, and West Syndrome:

Top Ranking Resources:

  1. Infantile Spasms | West Syndrome – Epilepsy Foundation
  2. Infantile Epileptic Spasms Syndrome – Epilepsy Action
  3. Infantile Epileptic Spasms Syndrome: Management and Prognosis – UpToDate
  4. Infantile Spasms – National Institute of Neurological Disorders and Stroke
  5. Infantile Spasms (for Parents) – KidsHealth
  6. Infantile Spasms – Mayo Clinic
  7. Infantile Spasms – WebMD
  8. Infantile Spasms – Cincinnati Children’s Hospital
  9. Infantile Spasms – Johns Hopkins Medicine
  10. West Syndrome (Infantile Spasms) – Epilepsy Research UK

Additional Reliable Sources:

  1. Infantile Spasms – American Academy of Pediatrics
  2. West Syndrome – Canadian Association for Epilepsy
  3. Infantile Spasms – Citizendium
  4. Infantile Spasms – PubMed Central
  5. Infantile Spasms: Little Seizures, BIG Consequences – PMC – NCBI

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