Infantile spasms

Last reviewed: March 2019

Last updated: November 2018

Summary

An epilepsy syndrome typically presenting in infancy, with a varying etiology.

Spasms may be flexor, extensor, mixed flexor-extensor, symmetric, or asymmetric, and typically occur in clusters.

A hypsarrhythmic electroencephalogram is characteristic but not universally present at all times.

A mortality rate of 5% to 30% is reported. Among survivors, developmental delay ensues in 80% to 90%, and 50% to 70% later develop other seizure types.

Treatment options include hormonal therapy (adrenocorticotropic hormone or corticosteroids) or vigabatrin.

Definition

Infantile spasms are the characteristic seizure type of West syndrome (infantile spasms, developmental plateau, and hypsarrhythmia). Age of onset is typically from 1 month to 1 year with a median age of 3 to 5 months. The seizures are characterized by an initial contraction phase followed by a more sustained tonic phase. The contractions may be flexor, extensor, or mixed flexor-extensor, with sudden, usually bilateral, symmetric contractions of the neck, trunk, and limbs. There may be an associated brief loss of consciousness. The seizures may be subtle, consisting of brief head nods, or be precipitated by sleep onset and offset or by feeding, leading to diagnostic confusion with gastroesophageal reflux. They typically occur in clusters or runs of 20 to 100 spasms at a time, with visible distress. Etiology is heterogeneous and, in a significant proportion, remains unidentified.

A hypsarrhythmic electroencephalogram pattern is characteristic, although not universally present. Onset of infantile spasms is often followed by plateauing or regression of subsequent development. West syndrome is thus the archetypal infantile epileptic encephalopathy. It is considered that rapid identification and treatment of the spasms improves prognosis.

History and exam

Key diagnostic factors

spasms
head nodding
neurodevelopmental delay or regression
ash leaf macules

Full details

Other diagnostic factors

onset age 3-12 months
perinatal complication
abnormal eye movements
microcephaly
motor system abnormalities

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Risk factors

brain malformation
neurocutaneous syndrome
prenatal or perinatal vascular event
intrauterine or perinatal infections
inherited metabolic disorder
genetic disorders
family history
neonatal sinovenous thrombosis
postnatal brain injury
brain tumors

Full details

Diagnostic investigations

1st investigations to order

EEG
plasma glucose
serum calcium
serum magnesium
LFTs
renal function tests
blood and urine cultures
CBC
microarray comparative genome hybridization (CGH)

Full details

Investigations to consider

brain MRI
brain CT
serum lactate/pyruvate
serum ammonia
serum amino acids
urine amino acids and organic acids
cytomegalovirus (CMV) culture, polymerase chain reaction (PCR), or serology
toxoplasmosis serology
echocardiogram
renal ultrasound
ophthalmology exam
biotinidase
urine alpha-amino adipic semialdehyde dehydrogenase
cerebrospinal fluid (CSF) exam
gene mutation analysis
chromosomal analysis

Full details

Treatment algorithm

ONGOING

all patients

Contributors

Authors VIEW ALL 

Robert Robinson, MA, MBBS, MRCP, PhD

Consultant Paediatric Neurologist

Great Ormond Street Hospital

London

Disclosures

RR declares that he has no competing interests.

Katharina Vezyroglou, MD

Clinical Fellow in Epilepsy

Great Ormond Street Hospital

London

Disclosures

KV declares that she has no competing interests.

Acknowledgements

Dr Robert Robinson and Dr Katharina Vezyroglou would like to gratefully acknowledge Dr Marjorie Illingworth, Dr Pradnya Gadgil, Dr Teesta Soman, and Dr Shelly Weiss, previous contributors to this monograph. MI, PG, TS, and SW declare that they have no competing interests.

Peer reviewers VIEW ALL 

Gregory L. Holmes, MD

Section Chief of Neurology

Dartmouth-Hitchcock Medical Center

Lebanon

Disclosures

GLH declares that he has no competing interests.

Maria Roberta Cilio, MD, PhD

Attending Pediatric Neurologist

Division of Neurology

Bambino Gesu Children's Hospital

Rome

Italy

Disclosures

MRC declares that she has no competing interests.

Lionel Carmant, MD

Professor of Neurology

Department of Pediatrics

University of Montreal

Director of Epilepsy Clinic and Research Group

Saint Justine Hospital

Montreal

Canada

Disclosures

LC declares that he has no competing interests.

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Infantile spasms

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

all patients

Contributors

Authors VIEW ALL 

Robert Robinson, MA, MBBS, MRCP, PhD

Disclosures

Katharina Vezyroglou, MD

Disclosures

Acknowledgements

Peer reviewers VIEW ALL 

Gregory L. Holmes, MD

Disclosures

Maria Roberta Cilio, MD, PhD

Disclosures

Lionel Carmant, MD

Disclosures

Differentials

Guidelines

Patient leaflets

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