Infantile Spasms (West Syndrome)

1. Clinical Overview

Summary

Infantile Spasms (IS), also known as West Syndrome or Infantile Epileptic Spasms Syndrome (IESS), is a severe age-specific epileptic encephalopathy predominantly affecting infants between 3-12 months of age. [1] It represents a paediatric neurological emergency requiring urgent recognition and treatment to optimise neurodevelopmental outcomes. [2]

The disorder is characterised by the classic triad:

1. Epileptic Spasms: Brief, sudden, symmetric or asymmetric muscle contractions (flexor, extensor, or mixed) occurring in clusters, typically on awakening. These movements are often described as "salaam attacks" (head-nodding bow) or "jackknife spasms" (sudden flexion of trunk and limbs). [3]

2. Developmental Regression or Arrest: Loss of previously acquired milestones (social smile, visual tracking, reaching) or failure to progress developmentally. This is a cardinal red flag indicating underlying encephalopathic process. [4]

3. Hypsarrhythmia: Chaotic, disorganised, high-amplitude (> 200 μV) interictal EEG pattern with multifocal independent spike-and-wave discharges and slow wave activity. This pathognomonic EEG finding reflects profound disruption of cortical organisation. [5,6]

Infantile spasms have diverse aetiologies including structural (cortical malformations, hypoxic-ischaemic encephalopathy, tuberous sclerosis complex), genetic (chromosomal abnormalities, monogenic disorders), metabolic, and unknown causes. [7] The prognosis is guarded, with 70-90% of affected infants developing intellectual disability, 30-50% developing autism spectrum disorder, and 50-70% progressing to refractory epilepsy including Lennox-Gastaut syndrome. [8,9]

First-line treatments are vigabatrin (particularly for tuberous sclerosis-associated cases) or high-dose hormonal therapy (ACTH or prednisolone). [10,11] The United Kingdom Infantile Spasms Study (UKISS) demonstrated superior short-term efficacy of hormonal therapy over vigabatrin for non-TSC cases, though long-term developmental outcomes were similar. [10] Time-critical treatment within 2-4 weeks of onset is associated with improved neurodevelopmental outcomes, emphasising the importance of early recognition and specialist referral. [12]

Clinical Pearls

"Salaam Attack" Recognition: The classic flexor spasm manifests as sudden flexion of neck, trunk, and arms in a bowing motion resembling a greeting gesture. Parents often describe these as "startles," "colic," or "reflux" initially, leading to diagnostic delay. Video recording by parents is invaluable for diagnosis.

Hypsarrhythmia is Diagnostic: High-amplitude (> 200 μV), chaotic, disorganised background with multifocal spikes. May be modified (asymmetric, attenuated during sleep, or with focal features). Ictal EEG during spasms shows electrodecremental response or generalised slow wave.

Developmental Regression = Red Flag: Loss of social smile, visual tracking, or motor milestones distinguishes epileptic spasms from benign conditions. This encephalopathic feature mandates urgent EEG and neuroimaging.

Tuberous Sclerosis = Vigabatrin: 80-90% of TSC-associated infantile spasms respond to vigabatrin, making it first-line for this aetiology. [13] However, vigabatrin carries risk of irreversible bilateral concentric visual field defects in up to 30-50% of treated children, requiring ophthalmological surveillance.

Treatment Urgency: The "therapeutic window" concept suggests early treatment (less than 4 weeks from onset) improves neurodevelopmental outcomes. Delay in diagnosis and treatment is associated with worse cognitive outcomes. [12]

Evolution to Lennox-Gastaut: 20-50% of infantile spasms cases evolve into Lennox-Gastaut syndrome (tonic/atonic seizures, slow spike-wave EEG, intellectual disability) by age 3-8 years, representing continued epileptic encephalopathy. [14]

---

2. Epidemiology

Demographics

Incidence and Prevalence:

• Incidence: 2-5 per 10,000 live births (approximately 1 in 2,000-5,000 infants). [1,15]
• Prevalence: Rare but represents 4-9% of all childhood epilepsies and is the most common epilepsy syndrome in the first year of life. [16]

Age and Gender:

Geographic and Ethnic Variations:

• No significant geographic variation in incidence has been consistently demonstrated.
• Genetic and metabolic aetiologies may vary by population (e.g., consanguinity increases autosomal recessive metabolic causes).

Aetiology and Classification

The International League Against Epilepsy (ILAE) 2017 classification categorises infantile spasms aetiologically: [17]

Key Aetiologic Considerations:

Exam Detail: Tuberous Sclerosis Complex (TSC):

• Accounts for 10-15% of all infantile spasms and is the single most common identifiable structural cause. [13]
• Caused by mutations in TSC1 (hamartin) or TSC2 (tuberin), leading to mTOR pathway hyperactivation.
• Cortical tubers, subependymal nodules, and subependymal giant cell astrocytomas (SEGAs) visible on MRI.
• Associated features: Hypomelanotic macules ("ash-leaf spots"), facial angiofibromas, cardiac rhabdomyomas, renal angiomyolipomas, pulmonary lymphangioleiomyomatosis (LAM) in adults.
• Vigabatrin is first-line treatment for TSC-associated infantile spasms with 80-90% response rate. [13]
• Emerging data support preventive vigabatrin in TSC infants with tubers on EEG monitoring before clinical spasms develop. [18]

Genetic Advances:

• Recent genomic studies (whole exome sequencing, chromosomal microarray) identify causative variants in 30-50% of previously "cryptogenic" cases. [7]
• ARX (X-linked): Associated with lissencephaly, intellectual disability, and dystonia.
• CDKL5 (X-linked dominant): Early-onset epileptic encephalopathy, profound developmental impairment, often refractory to treatment.
• STXBP1: Encodes syntaxin-binding protein; variable phenotype from isolated IS to severe encephalopathy.

Metabolic Causes:

• Pyridoxine (vitamin B6) dependency: Trial of IV pyridoxine during EEG is diagnostic/therapeutic.
• Biotinidase deficiency: Treatable with biotin supplementation; newborn screening now detects most cases.

---

3. Pathophysiology

Molecular and Network Mechanisms

The pathophysiology of infantile spasms remains incompletely understood, but involves a complex interplay of age-specific brain development, cortical-subcortical network dysfunction, and underlying aetiological insults. [19,20]

1. Age-Specific Vulnerability (3-12 Months)

The developing infant brain during the 3-12 month window exhibits unique vulnerabilities:

• Rapid synaptogenesis and myelination: Peak brain growth period with active formation of cortical circuits.
• Immature GABAergic signalling: GABA is initially excitatory in neonatal brain, transitioning to inhibitory; disruption during this critical period may promote epileptogenesis.
• Cortical-subcortical network maturation: Thalamocortical and brainstem-cortical networks are establishing functional connectivity; disruption leads to abnormal oscillatory activity.
• Neuromodulatory immaturity: Serotonergic, cholinergic, and other neuromodulatory systems are developing; dysfunction (e.g., brainstem serotonin or CRH pathways) may contribute to spasm generation. [21]

2. The "Two-Hit Hypothesis"

Many researchers propose a two-hit model: [19]

1. First hit: Underlying structural, genetic, or metabolic brain abnormality.
2. Second hit: Age-specific vulnerability of the developing brain (3-12 months) to this insult, resulting in the unique phenotype of epileptic spasms and hypsarrhythmia.

This explains why the same structural lesion (e.g., cortical dysplasia) may cause infantile spasms if present during the vulnerable period, but different seizure types if manifest later.

3. Cortical-Subcortical Network Dysfunction

Exam Detail: Hypsarrhythmia as a Biomarker of Network Chaos:

• Hypsarrhythmia reflects loss of normal cortical organisation and disruption of thalamocortical rhythms. [5,6]
• Characterised by:
  • High-amplitude (> 200 μV) slow waves (1-3 Hz).
  • Multifocal, independent spike discharges arising from multiple cortical regions asynchronously.
  • Absence of normal background rhythms (no organised posterior rhythm).
  • "Sleep modulation: Often more prominent in non-REM sleep; may attenuate or fragment during REM sleep."

Ictal Electrographic Pattern:

• During clinical spasms, EEG typically shows:
  • "Electrodecremental response: Sudden diffuse attenuation/flattening of EEG amplitude."
  • "High-amplitude slow wave: Generalised 1-2 Hz slow wave."
• These ictal patterns are brief (1-2 seconds), corresponding to the brief clinical spasm.

Brainstem and Subcortical Generators:

• Evidence suggests brainstem nuclei (raphe nuclei, locus coeruleus) and subcortical structures (basal ganglia, thalamus) play a role in spasm generation. [21]
• Corticotropin-releasing hormone (CRH) and serotonin pathways in brainstem are implicated, explaining efficacy of ACTH (which modulates CRH).

4. Epileptic Encephalopathy Concept

Infantile spasms are classified as an epileptic encephalopathy, meaning:

• The epileptic activity itself (spasms and interictal hypsarrhythmia) contributes to cognitive and developmental impairment, independent of the underlying aetiology. [22]
• This concept underpins the rationale for urgent treatment: suppressing epileptic activity may limit ongoing encephalopathic damage.
• However, developmental outcome is primarily determined by the underlying aetiology (structural/genetic lesion), though early seizure control may provide some benefit. [10,12]

5. mTOR Pathway Dysregulation (TSC and mTORopathies)

In tuberous sclerosis complex and other mTORopathies (focal cortical dysplasia type IIb, hemimegalencephaly):

• Loss of TSC1/TSC2 function leads to mTOR pathway hyperactivation.
• Results in: Abnormal neuronal migration, cortical dyslamination, dysmorphic neurons, and balloon cells.
• Cortical tubers are intrinsically epileptogenic.
• mTOR inhibitors (everolimus, rapamycin) are emerging as adjunctive therapies for refractory TSC-associated epilepsy, though not first-line for infantile spasms. [13]

---

4. Clinical Presentation

The Classic Triad of West Syndrome

Important Note: The full triad may not be present initially. Up to 30% of infants may not have documented hypsarrhythmia on initial EEG (may develop later, or have "modified" hypsarrhythmia). [23] Diagnosis should be suspected on clinical grounds (spasms + regression) even if initial EEG is non-diagnostic; repeat/prolonged EEG is warranted.

---

Semiology of Epileptic Spasms

Classification by Movement Type:

Cluster Characteristics:

• Clustering is cardinal: Spasms occur in series/clusters of 5 to > 100 spasms, with inter-spasm interval of 5-30 seconds. [3]
• Cluster duration: Typically 5-20 minutes, but can be prolonged.
• Frequency: Multiple clusters per day (range 2-50+ clusters/day).
• Circadian pattern: Prominent on awakening from sleep (nocturnal sleep or daytime naps). May also occur during drowsiness or occasionally when fully awake.

Associated Clinical Features:

• Cry or grimace: Spasms may be associated with crying (suggesting possible discomfort) or neutral expression.
• Autonomic features: Flushing, pallor, or pupillary dilation may occur but are uncommon.
• Post-ictal state: Typically no post-ictal impairment due to brief duration of spasms. Infant may be irritable after prolonged cluster.

Parental Description Pitfalls:

Parents commonly misinterpret spasms as:

• "Startle reflexes" or "Moro reflexes" (but these are not clustered).
• Colic or abdominal pain (due to flexion and crying).
• Gastro-oesophageal reflux or Sandifer syndrome (posturing).
• "Normal baby movements" or "stretching."

High index of suspicion and video review are essential when parents describe unusual repetitive movements, especially if associated with developmental concerns.

---

Developmental Regression and Encephalopathy

Developmental Red Flags:

Pattern of Developmental Impact:

• Regression (loss of previously acquired skills) is highly suggestive of infantile spasms.
• Developmental arrest (failure to progress) without clear regression may also occur, particularly in infants with pre-existing neurological abnormalities.
• Pre-existing developmental delay: 30-40% of infants have preceding neurodevelopmental abnormalities (due to underlying structural/genetic cause) before spasms onset. [8]

Autism Risk:

• Infantile spasms are a major risk factor for autism spectrum disorder, with 30-50% developing ASD by school age. [9]
• Mechanisms: Encephalopathic process during critical period for social brain development (6-24 months).

---

Modified and Atypical Presentations

Exam Detail: Modified Hypsarrhythmia:

Not all infants with infantile spasms have classic hypsarrhythmia. Modified patterns include: [5]

• Asymmetric hypsarrhythmia: Higher amplitude or more prominent spike activity over one hemisphere (suggests focal structural lesion).
• Hypsarrhythmia with increased interhemispheric synchrony: More organised bilateral spike-wave.
• Hypsarrhythmia with consistent focal abnormality: Persistent focal slowing or spikes superimposed on hypsarrhythmia (suggests focal lesion; may be surgical candidate).
• Absence of hypsarrhythmia: 10-30% may have other EEG abnormalities (multifocal spikes, diffuse slowing) without meeting hypsarrhythmia criteria, particularly later in disease course.

Late-Onset Infantile Spasms:

• Onset after 18 months (up to 3-4 years) is rare but recognised, termed "late infantile spasms."
• Often associated with specific aetiologies (e.g., late presentation of TSC, focal cortical dysplasia).
• Prognosis similar to typical age-onset cases.

Recurrence After Initial Remission:

• 20-30% of infants who achieve initial spasm cessation experience relapse (spasms recur). [24]
• Requires reinitiation or escalation of treatment.

---

5. Differential Diagnosis

Accurate differentiation from benign paroxysmal disorders and other seizure types is crucial to avoid unnecessary treatment or diagnostic delay.

Key Diagnostic Principle:

The combination of:

1. Epileptic spasms in clusters
2. Developmental regression/arrest
3. EEG abnormalities (hypsarrhythmia or multifocal epileptiform)

…is diagnostic of infantile spasms. Any infant with suspected spasms requires urgent video-EEG to confirm diagnosis.

---

6. Investigations

Electroencephalography (EEG) – The Diagnostic Cornerstone

Interictal EEG – Hypsarrhythmia:

Ictal EEG – During Spasms:

EEG Recommendations:

• Prolonged video-EEG (ideally capturing sleep and waking) is essential for diagnosis. [5,6]
• Sleep EEG: Hypsarrhythmia may be most prominent in non-REM sleep.
• Repeat EEG: If initial EEG is non-diagnostic but clinical suspicion remains high, repeat EEG (including sleep) is warranted. Up to 20-30% may not show hypsarrhythmia on first EEG.
• EEG monitoring during treatment: Repeat EEG after 2-4 weeks of treatment to assess for resolution of hypsarrhythmia (electrographic response correlates with clinical response).

EEG Grading:

• Recent studies have proposed semi-quantitative grading scales for hypsarrhythmia severity, which may have prognostic value and utility in monitoring treatment response. [6]

---

Neuroimaging – Essential for Aetiology

Magnetic Resonance Imaging (MRI) Brain:

Gold Standard: High-resolution MRI with epilepsy protocol is mandatory in all infants with infantile spasms. [7,25]

Key Structural Findings:

Timing of MRI:

• Should be performed urgently (within days to 1-2 weeks of diagnosis) to identify:
  • Potentially treatable lesions (e.g., focal cortical dysplasia amenable to surgery).
  • Conditions requiring specific management (e.g., TSC workup).
• MRI under general anaesthesia or sedation is typically required in this age group.

---

Genetic and Metabolic Investigations

Genetic Testing – Increasingly High Yield:

Modern genomic technologies identify causative genetic variants in 30-50% of cases, including many previously labelled "cryptogenic." [7]

Metabolic Screening:

When to Suspect Metabolic Cause:

• Consanguinity, family history of infantile deaths or unexplained epilepsy.
• Dysmorphic features, organomegaly, coarse facies.
• Metabolic decompensation (acidosis, hypoglycaemia, hyperammonaemia).
• Progressive neurodegeneration.

---

Multi-System Evaluation for Tuberous Sclerosis Complex

If TSC is suspected (cortical tubers on MRI, cardiac rhabdomyomas, hypomelanotic macules), comprehensive multi-system screening is required: [13]

TSC Diagnostic Criteria (updated 2012):

• Definite TSC: 2 major features OR 1 major + ≥2 minor features.
• Possible TSC: 1 major feature OR ≥2 minor features.
• Major criteria: Hypomelanotic macules (≥3, > 5mm), angiofibromas or fibrous cephalic plaque, ungual fibromas (≥2), shagreen patch, retinal hamartomas, cortical dysplasias (tubers, radial migration lines), subependymal nodules, subependymal giant cell astrocytoma, cardiac rhabdomyoma, lymphangioleiomyomatosis, angiomyolipomas (≥2).

---

7. Management

Management Principles and Urgency

Key Principles:

1. Time-Critical Treatment: Infantile spasms are a paediatric neurological emergency. Early treatment (within 2-4 weeks of spasm onset) is associated with better neurodevelopmental outcomes. [12]

2. Dual Treatment Goals:

   • Short-term: Cessation of clinical spasms and resolution of hypsarrhythmia (electroclinical remission).
   • Long-term: Optimise neurodevelopmental outcome and prevent epilepsy evolution.

3. Aetiology-Directed Therapy: Treatment choice influenced by underlying aetiology (vigabatrin first-line for TSC; hormonal therapy often preferred for non-TSC).

4. Multidisciplinary Approach: Paediatric neurologist, epilepsy specialist nurse, developmental paediatrician, physiotherapy, occupational therapy, speech therapy, educational support.

5. Family Support: Infantile spasms diagnosis is devastating for families; psychological support, parent education, and connection with support organisations are essential.

---

Management Algorithm

┌─────────────────────────────────────────────────────────────────────┐
│  SUSPECTED INFANTILE SPASMS                                         │
│  (Clusters of spasms + Developmental regression/arrest)             │
└────────────────────────────┬────────────────────────────────────────┘
                             ↓
┌─────────────────────────────────────────────────────────────────────┐
│  URGENT INVESTIGATIONS (Parallel)                                   │
│  • Video-EEG (capture sleep and waking; confirm hypsarrhythmia)     │
│  • MRI brain (epilepsy protocol; identify structural cause)         │
│  • Genetic: Chromosomal microarray + epilepsy gene panel            │
│  • Metabolic screen (lactate, amino acids, organic acids,           │
│    biotinidase, pyridoxine trial if indicated)                      │
│  • TSC evaluation if tubers/rhabdomyomas (skin, eyes, echo, renal)  │
└────────────────────────────┬────────────────────────────────────────┘
                             ↓
              ┌──────────────┴──────────────┐
              │  DIAGNOSIS CONFIRMED         │
              │  (EEG: Hypsarrhythmia)       │
              └──────────────┬───────────────┘
                             ↓
┌─────────────────────────────────────────────────────────────────────┐
│  AETIOLOGY-DIRECTED FIRST-LINE TREATMENT (Initiate within 2-4 weeks)│
└─────────────────────────────────────────────────────────────────────┘
                             ↓
        ┌────────────────────┴────────────────────┐
        │                                         │
        ↓                                         ↓
┌───────────────────────────┐       ┌─────────────────────────────────┐
│ TUBEROUS SCLEROSIS (TSC)  │       │ NON-TSC AETIOLOGY               │
│ (or strong suspicion)     │       │ (Structural/Genetic/Metabolic/  │
│                           │       │  Unknown)                       │
└───────────┬───────────────┘       └─────────────┬───────────────────┘
            ↓                                     ↓
    ┌───────────────────┐               ┌─────────────────────────────┐
    │ VIGABATRIN        │               │ HORMONAL THERAPY            │
    │ First-Line        │               │ First-Line                  │
    │                   │               │                             │
    │ Dose:             │               │ Option A: ACTH              │
    │ • Start: 50 mg/kg │               │ (Tetracosactide)            │
    │   /day (divided)  │               │ • 0.5-1 mg IM on alternate  │
    │ • Increase to     │               │   days (or 150 μg/kg/day    │
    │   100-150 mg/kg   │               │   up to 1 mg)               │
    │   /day over 3-7d  │               │ • Duration: 2-6 weeks, then │
    │                   │               │   taper over 2-4 weeks      │
    │ Response rate:    │               │                             │
    │ • TSC: 80-90%     │               │ Option B: Prednisolone      │
    │                   │               │ • 4 mg/kg/day (max 60 mg)   │
    │ Monitoring:       │               │   divided BD                │
    │ • Ophthalmology   │               │ • Duration: 2-4 weeks, then │
    │   baseline, then  │               │   taper over 4-8 weeks      │
    │   q3 months       │               │                             │
    │   (visual fields) │               │ Response rate: 60-75%       │
    │ • Risk: VF defect │               │                             │
    │   (30-50%)        │               │ Monitoring:                 │
    └─────────┬─────────┘               │ • BP, blood glucose, weight │
              │                         │ • Infection surveillance    │
              │                         │ • Electrolytes (K+)         │
              │                         │ • Gastric protection (PPI)  │
              │                         └─────────────┬───────────────┘
              └──────────────┬──────────────────────┘
                             ↓
┌─────────────────────────────────────────────────────────────────────┐
│  ASSESS RESPONSE AT 2-4 WEEKS                                       │
│  Clinical: Spasm cessation                                          │
│  Electrographic: Repeat EEG – resolution/improvement hypsarrhythmia │
└─────────────────────────────────────────────────────────────────────┘
                             ↓
              ┌──────────────┴──────────────┐
              ↓                             ↓
    ┌─────────────────────┐       ┌──────────────────────────────────┐
    │ RESPONSE            │       │ NO RESPONSE / PARTIAL RESPONSE   │
    │ (Spasms ceased,     │       │ (Spasms persist)                 │
    │  EEG improved)      │       │                                  │
    └──────────┬──────────┘       └─────────────┬────────────────────┘
               ↓                                 ↓
    ┌────────────────────┐         ┌────────────────────────────────┐
    │ CONTINUE TREATMENT │         │ SECOND-LINE OPTIONS:           │
    │ • Vigabatrin:      │         │                                │
    │   Continue 6-12mo  │         │ 1. SWITCH THERAPY:             │
    │   then wean        │         │    • ACTH → Vigabatrin         │
    │ • ACTH/Pred:       │         │    • Vigabatrin → ACTH/Pred    │
    │   Taper as planned │         │                                │
    │                    │         │ 2. COMBINATION THERAPY:        │
    │ Add maintenance AED│         │    • Vigabatrin + ACTH/Pred    │
    │ if needed (many    │         │                                │
    │ require long-term  │         │ 3. OTHER AEDs:                 │
    │ AEDs despite spasm │         │    • Topiramate                │
    │ cessation)         │         │    • Zonisamide                │
    └──────────┬─────────┘         │    • Nitrazepam/Clobazam       │
               │                   │    • Valproate (beware less than 2yr)   │
               │                   │                                │
               │                   │ 4. KETOGENIC DIET              │
               │                   │                                │
               │                   │ 5. EPILEPSY SURGERY:           │
               │                   │    If FOCAL LESION (FCD, single│
               │                   │    TSC tuber, stroke) – Consider│
               │                   │    resection/disconnection     │
               └───────────────────┴────────────┬───────────────────┘
                                                ↓
┌─────────────────────────────────────────────────────────────────────┐
│  LONG-TERM FOLLOW-UP (Mandatory)                                    │
│  • Developmental surveillance (PT, OT, SLT, educational support)    │
│  • Epilepsy monitoring (50-70% develop other seizure types)         │
│  • Ophthalmology monitoring (if vigabatrin exposure)                │
│  • Autism screening (MCHAT at 18-24 months)                         │
│  • Management of underlying condition (TSC: cardiac, renal, SEGA    │
│    surveillance; genetic counselling if hereditary condition)       │
│  • Family support and psychological services                        │
└─────────────────────────────────────────────────────────────────────┘

---

First-Line Pharmacotherapy

1. Vigabatrin

Indications:

• First-line for Tuberous Sclerosis Complex-associated infantile spasms (80-90% response rate). [13]
• Alternative first-line for non-TSC cases (though UKISS trial showed hormonal therapy more effective for non-TSC). [10]

Mechanism of Action:

• Irreversible inhibitor of GABA transaminase → increases brain GABA levels.

Dosing:

Response Timeline:

• Most responders show clinical improvement within 2 weeks.
• If no response by 4 weeks at adequate dose, unlikely to respond; consider switching therapy.

Adverse Effects:

Monitoring:

• Ophthalmology: Baseline (before starting), then every 3 months during treatment, and 3-6 months post-discontinuation.
  • "Infants: Electroretinography (ERG), visual evoked potentials (VEP)."
  • "Older children: Perimetry (visual field testing) when developmentally able."
• Clinical response: Spasm diary, developmental assessment.
• EEG at 2-4 weeks to assess electrographic response.

---

2. Hormonal Therapy

A. ACTH (Adrenocorticotropic Hormone) – Tetracosactide

Indications:

• Preferred first-line for non-TSC infantile spasms (based on UKISS trial). [10]
• UKISS showed 73% clinical response (spasm cessation) with ACTH vs 54% with vigabatrin in non-TSC cases, though 14-month developmental outcomes were similar.

Mechanism of Action:

• Stimulates adrenal cortex to produce cortisol.
• Direct neuronal effects via melanocortin receptors (MC1-MC5).
• Modulates corticotropin-releasing hormone (CRH) pathways implicated in spasm generation.

Dosing:

Response Timeline:

• Majority of responders show improvement within 2 weeks.

Adverse Effects (Common and Serious):

Monitoring:

• Blood pressure: Baseline, then weekly during treatment.
• Electrolytes (Na+, K+), glucose: Baseline, weekly during treatment.
• Weight, growth: Monitor for Cushingoid features.
• Infection surveillance: Low threshold for assessment if fever or illness.
• EEG at 2-4 weeks to assess response.

Contraindications/Cautions:

• Active infection (relative; treat infection first).
• Live vaccines (avoid during and for 3 months after ACTH).

---

B. High-Dose Prednisolone

Indications:

• Alternative to ACTH for non-TSC infantile spasms (easier to administer; oral vs IM).
• Some evidence suggests slightly lower efficacy than ACTH, but differences are modest. [11]

Dosing:

Response and Adverse Effects:

• Similar to ACTH (hypertension, irritability, infection risk, Cushingoid features, electrolyte disturbance).
• Same monitoring requirements as ACTH.

Comparison: ACTH vs Prednisolone:

Many centres use prednisolone as first-line hormonal therapy due to ease of administration, with ACTH reserved for prednisolone non-responders.

---

Second-Line and Adjunctive Therapies

1. Switching Between Vigabatrin and Hormonal Therapy

• If vigabatrin fails: Switch to ACTH/prednisolone (response rate 30-50% in vigabatrin non-responders).
• If hormonal therapy fails: Switch to vigabatrin (response rate ~40% in hormonal non-responders).

2. Combination Therapy (Vigabatrin + Hormonal)

• Some evidence suggests combination vigabatrin + ACTH/prednisolone may be more effective than monotherapy in difficult cases. [11]
• Increased risk of adverse effects (additive); used in refractory cases.

3. Other Antiepileptic Drugs

4. Ketogenic Diet

• High-fat, low-carbohydrate metabolic therapy.
• Evidence: Several studies report 30-60% response rate (≥50% spasm reduction) in drug-refractory infantile spasms. [26]
• Practical challenges: Requires specialist dietitian support, precise formula/food preparation, monitoring for adverse effects (constipation, growth, kidney stones, acidosis).
• Timing: Typically considered after failure of first- and second-line pharmacotherapy, or earlier if specific metabolic indication (e.g., GLUT1 deficiency, pyruvate dehydrogenase deficiency).

5. Cannabidiol (CBD)

• Emerging interest; limited data specifically for infantile spasms.
• May be considered in highly refractory cases as adjunctive therapy (requires specialist epilepsy centre).

6. Immunotherapies (Experimental)

• Intravenous immunoglobulin (IVIG), rituximab (anti-CD20), corticosteroids: Rarely used; case reports/small series suggest potential benefit in immune-mediated or post-infectious cases.
• Not standard of care; specialist consultation required.

---

Epilepsy Surgery

Indications:

Infantile spasms secondary to focal structural lesions may be surgically remediable, with excellent outcomes in selected cases. [27]

Evaluation:

• Video-EEG telemetry: Localise ictal onset (electrodecremental response may be diffuse even with focal lesion; careful interpretation needed).
• High-resolution MRI: Identify focal lesion.
• Functional imaging (PET, SPECT – less commonly used in infants).
• Multidisciplinary epilepsy surgery conference: Paediatric neurologist, neurosurgeon, neuroradiologist, neuropsychologist.

Timing:

• Surgery should be considered early in appropriate candidates (within months of diagnosis) if medical therapy fails, as ongoing spasms/hypsarrhythmia contribute to developmental impairment.

---

Management of Underlying Aetiology

---

Long-Term Monitoring and Neurodevelopmental Support

Epilepsy Follow-Up:

• 50-70% develop other seizure types (focal, generalised tonic-clonic, atonic, tonic, myoclonic) after spasms cease. [14]
• Evolution to Lennox-Gastaut Syndrome: 20-50% progress to LGS (multiple seizure types, slow spike-wave EEG, intellectual disability) by age 3-8 years.
• AED management: Many require long-term antiepileptic drugs even after spasm cessation.

Neurodevelopmental Support:

Ophthalmology Monitoring (if Vigabatrin Exposure):

• Continue visual field assessment every 3-6 months for at least 6-12 months after vigabatrin discontinuation.
• Lifelong monitoring recommended (visual field defects may develop years after stopping).

---

8. Complications and Prognosis

Neurodevelopmental Outcomes

Overall Prognosis is Guarded:

---

Prognostic Factors

Factors Associated with BETTER Prognosis:

Factors Associated with WORSE Prognosis:

---

UKISS Trial – Long-Term Outcome Data

The United Kingdom Infantile Spasms Study (UKISS) is the landmark randomised controlled trial comparing hormonal therapy (prednisolone) vs vigabatrin: [10,18]

Key Findings:

Interpretation:

• Hormonal therapy is more effective than vigabatrin for short-term spasm cessation in non-TSC infantile spasms.
• However, long-term developmental and epilepsy outcomes at 4 years were similar, suggesting that:
  • Underlying aetiology is the dominant determinant of long-term outcome.
  • Early seizure control provides modest benefit, but does not overcome the impact of underlying brain pathology.
• TSC subgroup: Vigabatrin was superior in TSC cases (80-90% response), confirming vigabatrin as first-line for TSC.

---

Mortality

• Mortality rate: 5-10% in first few years (higher in severe underlying aetiologies – HIE, genetic syndromes, refractory epilepsy). [1,8]
• Causes of death: Underlying condition (e.g., severe HIE, metabolic disease), status epilepticus, sudden unexpected death in epilepsy (SUDEP – rare in infants but risk increases with ongoing refractory epilepsy).

---

Relapse

• Relapse rate: 20-30% of infants who achieve initial remission experience recurrence of spasms. [24]
• Management: Reinitiate or escalate treatment; consider alternative therapies.
• Prognosis: Relapse does not necessarily predict worse long-term outcome if retreatment is effective.

---

9. Prevention

Primary Prevention

Currently, no effective primary prevention exists for most cases of infantile spasms, as underlying aetiologies (genetic, structural) are often not preventable.

Potential Preventive Strategies:

---

Secondary Prevention (Early Intervention)

Goal: Minimise neurodevelopmental impact once spasms occur.

• Early recognition and diagnosis: High index of suspicion in infants with clusters of spasms or developmental regression; urgent referral to paediatric neurology.
• Time-critical treatment: Initiate first-line therapy within 2-4 weeks of diagnosis. [12]
• Electroclinical remission target: Aim for both spasm cessation and EEG normalisation (not just clinical improvement).

---

10. Evidence and Guidelines

Key International Guidelines

---

Landmark Trials and Systematic Reviews

---

Evidence Grading for Treatments

---

11. Patient and Layperson Explanation

What are Infantile Spasms?

Infantile Spasms are a type of epilepsy (seizures) that affects babies, usually between 3 and 12 months old. The seizures look like sudden, brief jerking or stiffening movements – often the baby bends forward at the waist (like a "jackknife") or throws their arms out. These movements happen in clusters (many in a row, seconds apart), especially when the baby is waking up from sleep.

Why is this a serious condition?

Infantile Spasms are serious because:

1. Brain Development: They happen at a critical time for your baby's brain development. The abnormal electrical activity in the brain can interfere with learning and development.
2. Developmental Regression: Babies with Infantile Spasms often lose skills they already had – for example, they may stop smiling, stop making eye contact, or stop reaching for toys. This is a major warning sign.
3. Long-term Challenges: Without treatment, most babies with Infantile Spasms will have learning difficulties, and many will continue to have epilepsy as they grow older.

What causes Infantile Spasms?

There are many possible causes:

• Brain structure problems: Problems with how the brain formed before birth, or brain injury during birth.
• Genetic conditions: Such as Tuberous Sclerosis (a condition where small growths develop in the brain and other organs).
• Metabolic disorders: Rare conditions affecting the body's chemistry.
• Unknown: In about 20-30% of babies, doctors cannot find a specific cause even after thorough testing. These babies tend to have a better outlook.

How is it diagnosed?

Your doctor will:

• Watch a video of the movements (you can record them on your phone – this is very helpful!).
• Perform an EEG (brain wave test): This shows a very abnormal pattern called "hypsarrhythmia" in babies with Infantile Spasms.
• Do an MRI scan of the brain to look for any structural problems.
• Perform genetic and metabolic tests (blood and urine tests) to look for underlying causes.

How is it treated?

Treatment needs to start urgently – within 2-4 weeks of diagnosis. Early treatment gives the best chance of protecting your baby's development.

The two main treatments are:

1. Vigabatrin (a seizure medicine):

   • Given as liquid medicine twice a day.
   • Works very well (80-90%) if the cause is Tuberous Sclerosis.
   • Important side effect: Can cause permanent vision problems (loss of peripheral vision) in 30-50% of children. Your baby will need regular eye tests.

2. Steroid treatment (ACTH injections or prednisolone tablets):

   • Injections (ACTH) are given into the muscle every other day, or high-dose steroid tablets (prednisolone) are given daily.
   • Works well in about 70% of babies.
   • Side effects: High blood pressure, irritability, increased risk of infections, weight gain. Your baby will need close monitoring.

The doctor will choose the treatment based on the underlying cause and discuss the benefits and risks with you.

What is the outlook for my baby?

The outlook varies greatly depending on the underlying cause:

• Best outlook: Babies where no cause is found ("cryptogenic") and who respond quickly to treatment. About 30-40% of these babies may develop normally or near-normally.
• Guarded outlook: Overall, 70-90% of babies with Infantile Spasms will have some degree of learning difficulty, and 30-50% may develop autism. About half will continue to have epilepsy.
• Worst outlook: Babies with severe brain abnormalities or certain genetic conditions tend to have more significant challenges.

Your baby's treatment team (neurologist, developmental specialist, therapists) will work with you to give your baby the best possible support for development, including:

• Physiotherapy
• Occupational therapy
• Speech therapy
• Educational support

What support is available?

• Infantile Spasms Action Network: https://www.infantilespasms.org (US)
• Epilepsy Society (UK): https://epilepsysociety.org.uk
• Young Epilepsy (UK): https://www.youngepilepsy.org.uk
• Tuberous Sclerosis Association (if TSC diagnosis): https://www.tuberous-sclerosis.org (UK), https://www.tsalliance.org (US)

Questions you might want to ask your doctor:

• What is the likely cause of my baby's spasms?
• Which treatment do you recommend, and why?
• What are the risks and side effects of treatment?
• What tests will my baby need?
• What is the likely outlook for my baby's development?
• What support services are available for our family?

Remember: Early treatment gives the best chance of helping your baby. Your medical team is here to support you and your baby every step of the way.

---

12. Examination Focus (MRCPCH / Paediatric Neurology)

High-Yield Exam Topics

Core Knowledge (Essential for MRCPCH, Paediatric Neurology Exams):

1. Classic Triad of West Syndrome: Epileptic spasms, developmental regression, hypsarrhythmia.
2. EEG Findings: Hypsarrhythmia (chaotic, high-amplitude, multifocal spikes); ictal electrodecremental response.
3. First-Line Treatments: Vigabatrin (TSC), Hormonal therapy (ACTH/prednisolone, non-TSC).
4. UKISS Trial: Hormonal therapy superior to vigabatrin for short-term spasm cessation in non-TSC; no difference in long-term development.
5. Vigabatrin Toxicity: Irreversible bilateral concentric visual field defects (30-50%); requires ophthalmology monitoring.
6. Tuberous Sclerosis Complex: Major cause of IS (10-15%); multi-system disease (brain tubers, cardiac rhabdomyomas, renal angiomyolipomas, skin lesions).
7. Prognosis: 70-90% intellectual disability; 30-50% ASD; 50-70% ongoing epilepsy; 20-50% evolve to Lennox-Gastaut Syndrome.
8. Cryptogenic/Unknown Aetiology: Best prognosis (30-40% may have normal/near-normal development).

---

Common Exam Questions (MCQs, SAQs, Vivas)

1. MCQ: West Syndrome Triad

Question: A 6-month-old infant presents with clusters of brief flexion movements on waking, loss of social smile, and developmental regression. EEG shows high-amplitude chaotic background with multifocal spikes. Which feature is NOT part of the classic triad of West Syndrome?

A. Hypsarrhythmia on EEG
B. Developmental regression
C. Fever-triggered seizures
D. Epileptic spasms in clusters

Answer: C (Fever-triggered seizures are characteristic of Dravet Syndrome, not West Syndrome)

---

2. SAQ: First-Line Treatment

Question: A 5-month-old infant is diagnosed with infantile spasms. MRI brain shows multiple cortical tubers, and echocardiography reveals cardiac rhabdomyomas. What is the first-line treatment and why?

Model Answer:

• Diagnosis: Tuberous Sclerosis Complex (cortical tubers + cardiac rhabdomyomas).
• First-line treatment: Vigabatrin.
• Rationale: Vigabatrin is highly effective in TSC-associated infantile spasms (80-90% response rate). Evidence suggests superior efficacy for TSC compared to hormonal therapy.
• Monitoring: Ophthalmology surveillance (baseline and every 3 months) for visual field defects (irreversible complication in 30-50%).

---

3. Viva: UKISS Trial

Question: "Tell me about the UKISS trial and its implications for treatment of infantile spasms."

Model Answer:

• UKISS: United Kingdom Infantile Spasms Study (Lux et al., Lancet Neurology 2005).
• Design: Randomised controlled trial comparing hormonal therapy (prednisolone) vs vigabatrin in 214 infants with newly diagnosed infantile spasms.
• Primary outcome: Cessation of spasms at 2 weeks.
• Results:
  • "Hormonal therapy: 73% spasm cessation (non-TSC cases)."
  • "Vigabatrin: 54% spasm cessation (non-TSC)."
  • "Statistical significance: P=0.0026 – hormonal therapy superior for short-term efficacy."
  • "TSC subgroup: Vigabatrin superior (80-90% response)."
• Long-term follow-up (4 years):
  • No significant difference in developmental quotient, epilepsy prevalence, or neurodevelopmental impairment between groups.
  • "Interpretation: Underlying aetiology is dominant determinant of long-term outcome; early seizure control provides modest benefit."
• Implications:
  • Hormonal therapy (ACTH/prednisolone) preferred for non-TSC infantile spasms.
  • Vigabatrin preferred for TSC-associated infantile spasms.

---

4. Viva: Management of Refractory Infantile Spasms

Question: "A 7-month-old with infantile spasms has failed both vigabatrin and ACTH. MRI shows focal cortical dysplasia in the right frontal lobe. What are your next steps?"

Model Answer:

Second-Line Medical Options:

• Combination therapy: Vigabatrin + ACTH/prednisolone (if not already tried).
• Alternative AEDs: Topiramate, zonisamide, clobazam.
• Ketogenic diet: Evidence for 30-60% response rate in drug-refractory cases.

Surgical Evaluation (High Priority for Focal Structural Lesion):

• Rationale: Focal cortical dysplasia is a potentially surgically remediable lesion. Early surgery may achieve seizure freedom and improve neurodevelopmental outcome.
• Workup:
  • "Prolonged video-EEG telemetry: Localise ictal onset (correlate with MRI lesion)."
  • "Multidisciplinary epilepsy surgery conference: Neurology, neurosurgery, neuroradiology, neuropsychology."
  • "Functional imaging (if needed): PET, SPECT."
• Surgical approach: Focal resection/lesionectomy of right frontal focal cortical dysplasia.
• Expected outcome: 60-80% seizure-freedom if complete resection of epileptogenic zone.

Rationale for Early Surgery:

• Ongoing spasms and hypsarrhythmia contribute to developmental impairment (epileptic encephalopathy).
• Early surgical intervention (within months of diagnosis) in appropriate candidates may limit encephalopathic damage.

---

5. Data Interpretation: EEG

Question: You are shown an EEG with high-amplitude (300-400 μV) chaotic slow waves, multifocal independent spike discharges, and no organised background rhythm. What is the diagnosis and significance?

Model Answer:

• EEG diagnosis: Hypsarrhythmia.
• Clinical significance: Pathognomonic interictal EEG pattern of infantile spasms (West syndrome).
• Features:
  • High-amplitude (> 200 μV) slow waves.
  • Multifocal independent spikes (asynchronous).
  • Chaotic, disorganised background; no normal posterior rhythm.
  • May be modified (asymmetric, focal features, or attenuated).
• Ictal EEG (during spasm): Electrodecremental response (voltage attenuation) or generalised slow wave.
• Management: Urgent treatment (vigabatrin or hormonal therapy) to achieve electroclinical remission (spasm cessation + EEG normalisation).

---

6. Clinical Scenario: Diagnosis

Question: A 5-month-old infant is brought to A&E by parents who describe "odd movements" for 1 week. On video review, you see clusters of 10-15 brief episodes where the infant suddenly flexes the neck, trunk, and arms (lasting 1-2 seconds each), with 5-10 second intervals between episodes. The clusters occur mainly on waking. Parents report the baby has stopped smiling and making eye contact over the past month. Examination is otherwise unremarkable. What is your diagnosis and immediate management?

Model Answer:

Diagnosis: Infantile Spasms (West Syndrome) – highly likely.

Reasoning:

• Semiology: Clusters of brief flexion spasms (1-2 seconds, 5-10 second inter-spasm interval), on waking – classic.
• Developmental regression: Loss of social smile and eye contact – red flag for encephalopathy.
• Age: 5 months – typical age of onset.

Immediate Management:

1. Urgent Admission: Infantile spasms are a paediatric neurological emergency.

2. Urgent Investigations:

   • Video-EEG (same day or next day): Confirm hypsarrhythmia; capture ictal events.
   • MRI brain (within 1 week): Epilepsy protocol to identify structural cause.
   • Genetic testing: Chromosomal microarray, epilepsy gene panel.
   • Metabolic screen: Plasma amino acids, urine organic acids, lactate, ammonia, biotinidase.
   • TSC workup: Skin examination (Wood's lamp for hypomelanotic macules), ophthalmology (fundoscopy), echocardiography, renal ultrasound.

3. Initiate Treatment (within 2-4 weeks of diagnosis):

   • If TSC suspected/confirmed: Vigabatrin first-line.
   • If non-TSC: Hormonal therapy (ACTH or high-dose prednisolone) first-line.
   • Counsel parents on risks/benefits; obtain informed consent; arrange monitoring (BP, ophthalmology as appropriate).

4. Referral: Paediatric neurology/epilepsy specialist (if not already involved).

5. Family Support: Explain diagnosis, prognosis, treatment plan; provide written information; connect with support organisations.

---

Viva Scenarios (Oral Examination)

Scenario 1: Ethical Dilemma – Vigabatrin Visual Toxicity

Examiner: "You are discussing treatment options for a 6-month-old with TSC-associated infantile spasms. The parents are very concerned about the risk of visual field defects with vigabatrin. How do you counsel them?"

Model Answer:

Acknowledge Concerns:

• "I understand your concern about vigabatrin's side effect on vision. This is a serious consideration, and I want to explain the risks and benefits fully."

Explain Vigabatrin Efficacy:

• "Vigabatrin is the most effective treatment for infantile spasms caused by Tuberous Sclerosis, with an 80-90% success rate in stopping the spasms. This is significantly better than other treatments for TSC-related spasms."

Explain Visual Toxicity Risk:

• "Vigabatrin can cause permanent loss of peripheral (side) vision in 30-50% of children who take it. This means your child may have reduced ability to see to the sides, though central vision (for reading, recognising faces) is usually preserved."
• "We cannot predict which children will be affected, and the defect is irreversible even after stopping the medication."

Explain Monitoring:

• "We will monitor your child's vision carefully with specialist eye tests (electroretinography/ERG and visual evoked potentials/VEP in infants, visual field tests when older) before starting vigabatrin, then every 3 months during treatment, and for some time after stopping."

Risk-Benefit Discussion:

• "Without treatment, infantile spasms cause ongoing brain dysfunction and developmental damage. 70-90% of untreated infants develop significant learning difficulties, and many have autism and ongoing epilepsy."
• "Early, effective treatment gives the best chance to protect your child's brain development. For TSC, vigabatrin is the treatment most likely to work."
• "The visual field loss, while serious, is usually peripheral (side vision). Most children adapt well and can still function normally for most activities, though driving may be affected in adulthood."

Alternative Options:

• "The alternative is hormonal therapy (ACTH or steroids), which has different side effects (high blood pressure, infection risk, irritability) and is less effective for TSC (about 50-60% success rate)."
• "If vigabatrin fails, we would try hormonal therapy next anyway."

Shared Decision-Making:

• "I recommend vigabatrin as first-line treatment because it offers the best chance of stopping the spasms and protecting development in TSC. However, the decision is yours, and I respect whatever you choose after considering the information."
• "Would you like time to think about this, or do you have further questions?"

---

Scenario 2: Prognostic Counselling

Examiner: "The parents of a 6-month-old with newly diagnosed infantile spasms (unknown cause, normal MRI, awaiting genetic results) ask you, 'Will our baby be normal?' How do you respond?"

Model Answer:

Empathy and Honesty:

• "I understand this is an incredibly difficult time, and you want to know what the future holds for your baby. I'll be as honest as I can, though there is some uncertainty."

Explain Variability:

• "The outlook for babies with infantile spasms varies greatly depending on the underlying cause and how well they respond to treatment."

Positive Factors in This Case:

• "There are some positive signs in your baby's case:
  • The brain MRI is normal – no structural damage visible.
  • The cause is unknown (we call this 'cryptogenic'). Babies with unknown causes tend to have better outcomes than those with identified brain abnormalities or genetic conditions.
  • Your baby had normal development before the spasms started – this is a good sign."

Realistic Prognosis:

• "In babies like yours – with unknown cause and normal MRI – about 30-40% develop normally or nearly normally, especially if they respond quickly to treatment."
• "However, I must also be honest that overall, 70-90% of babies with infantile spasms have some degree of learning difficulty, and 30-50% may develop autism. About half continue to have epilepsy."
• "The underlying cause (which we may identify with genetic testing) and how quickly the spasms respond to treatment are the biggest factors affecting outcome."

Importance of Treatment:

• "This is why we are starting treatment urgently. Early, effective treatment gives the best chance of protecting your baby's development."

Ongoing Support:

• "We will monitor your baby's development very closely and provide all the support needed – physiotherapy, occupational therapy, speech therapy, educational support – whatever is required."
• "I will keep you informed as we learn more from the genetic tests and as we see how your baby responds to treatment."

Hope and Realism:

• "There is real hope for your baby, particularly given the positive factors we've discussed. But I want you to be prepared that this is a serious condition, and we may face challenges. We will support you every step of the way."

---

Red Flag Recognition (OSCEs / Clinical Stations)

Scenario: Parent brings 5-month-old to GP with video of "funny movements."

Red Flags for Infantile Spasms (Urgent Referral Required):

Action: Same-day paediatric referral (or direct A&E if out of hours). Infantile spasms are a time-critical neurological emergency.

---

13. References

Primary Literature (PubMed Citations)

1. Pavone P, Striano P, Falsaperla R, et al. West syndrome: a comprehensive review. Neurol Sci. 2020;41(12):3547-3562. PMID: 32827285. DOI: 10.1007/s10072-020-04600-5

2. Snyder HE, Jain A, Helbig I. Genetic Advancements in Infantile Epileptic Spasms Syndrome and Opportunities for Precision Medicine. Genes (Basel). 2024;15(3):382. PMID: 38540325. DOI: 10.3390/genes15030382

3. Lux AL, Edwards SW, Hancock E, et al. The United Kingdom Infantile Spasms Study (UKISS) comparing hormone treatment with vigabatrin on developmental and epilepsy outcomes to age 14 months: a multicentre randomised trial. Lancet Neurol. 2005;4(11):712-717. PMID: 16239177. DOI: 10.1016/S1474-4422(05)70199-X

4. Pellock JM, Hrachovy R, Shinnar S, et al. Infantile spasms: a U.S. consensus report. Epilepsia. 2010;51(10):2175-2189. PMID: 20608959. DOI: 10.1111/j.1528-1167.2010.02657.x

5. Mytinger JR, Joshi S. A reliable interictal EEG grading scale for children with infantile spasms - The IS-EEG score. Epilepsy Res. 2021;173:106617. PMID: 33839516. DOI: 10.1016/j.eplepsyres.2021.106617

6. Hrachovy RA, Frost JD Jr. Infantile epileptic encephalopathy with hypsarrhythmia (infantile spasms/West syndrome). J Clin Neurophysiol. 2003;20(6):408-425. PMID: 14734931. DOI: 10.1097/00004691-200311000-00004

7. Zhu L, Wang Y, An J, et al. Infantile epileptic spasms syndrome: an etiologic study of 361 patients with infantile spasms. Front Pediatr. 2024;12:1507809. PMID: 39850204. DOI: 10.3389/fped.2024.1507809

8. Riikonen R. Long-term outcome of West syndrome: a study of adults with a history of infantile spasms. Epilepsia. 1996;37(4):367-372. PMID: 8603642. DOI: 10.1111/j.1528-1157.1996.tb00573.x

9. Askalan R, Mackay M, Brian J, et al. Prospective preliminary analysis of the development of autism and epilepsy in children with infantile spasms. J Child Neurol. 2003;18(3):165-170. PMID: 12731639. DOI: 10.1177/08830738030180030201

10. Lux AL, Edwards SW, Hancock E, et al. 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. PMID: 15541450. DOI: 10.1016/S0140-6736(04)17400-X

11. Hancock EC, Osborne JP, Edwards SW. Treatment of infantile spasms. Cochrane Database Syst Rev. 2013;(6):CD001770. PMID: 23740534. DOI: 10.1002/14651858.CD001770.pub3

12. Kivity S, Lerman P, Ariel R, et al. Long-term cognitive outcomes of a cohort of children with cryptogenic infantile spasms treated with high-dose adrenocorticotropic hormone. Epilepsia. 2004;45(3):255-262. PMID: 15009226. DOI: 10.1111/j.0013-9580.2004.33503.x

13. Curatolo P, Bombardieri R, Jozwiak S. Tuberous sclerosis. Lancet. 2008;372(9639):657-668. PMID: 18722871. DOI: 10.1016/S0140-6736(08)61279-9

14. Montenegro MA, Cendes F, Guerreiro MM, Guerreiro CA. Epilepsy associated with chromosomal disorders. Epilepsy Behav. 2025;162:110238. PMID: 40179454. DOI: 10.1016/j.yebeh.2024.110238

15. Cowan LD. The epidemiology of the epilepsies in children. Mental Retard Dev Disabil Res Rev. 2002;8(3):171-181. PMID: 12216060. DOI: 10.1002/mrdd.10035

16. Trevathan E, Murphy CC, Yeargin-Allsopp M. Prevalence and descriptive epidemiology of Lennox-Gastaut syndrome among Atlanta children. Epilepsia. 1997;38(12):1283-1288. PMID: 9578522. DOI: 10.1111/j.1528-1157.1997.tb00064.x

17. Scheffer IE, Berkovic S, Capovilla G, et al. ILAE classification of the epilepsies: Position paper of the ILAE Commission for Classification and Terminology. Epilepsia. 2017;58(4):512-521. PMID: 28276062. DOI: 10.1111/epi.13709

18. Kotulska K, Kwiatkowski DJ, Curatolo P, et al. Prevention of epilepsy in infants with tuberous sclerosis complex in the EPISTOP trial. Ann Neurol. 2021;89(2):304-314. PMID: 33165960. DOI: 10.1002/ana.25956

19. Frost JD Jr, Hrachovy RA. Pathogenesis of infantile spasms: a model based on developmental desynchronization. J Clin Neurophysiol. 2005;22(1):25-36. PMID: 15689709.

20. Lado FA, Moshé SL. How do seizures stop? Epilepsia. 2008;49(10):1651-1664. PMID: 18503563. DOI: 10.1111/j.1528-1167.2008.01669.x

21. Chugani HT, Ilyas M, Kumar A, et al. Surgical treatment for refractory epileptic spasms: The Detroit series. Epilepsia. 2015;56(12):1941-1949. PMID: 26530058. DOI: 10.1111/epi.13221

22. Berg AT, Berkovic SF, Brodie MJ, et al. Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005-2009. Epilepsia. 2010;51(4):676-685. PMID: 20196795. DOI: 10.1111/j.1528-1167.2010.02522.x

23. Koo B, Hwang PA, Logan WJ. Infantile spasms: outcome and prognostic factors of cryptogenic and symptomatic groups. Neurology. 1993;43(11):2322-2327. PMID: 8232953. DOI: 10.1212/wnl.43.11.2322

24. Go CY, Mackay MT, Weiss SK, et al. 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;78(24):1974-1980. PMID: 22689735. DOI: 10.1212/WNL.0b013e318259e2cf

25. Widjaja E, Zarei Mahmoodabadi S, Otsubo H, et al. Subcortical alterations in tissue microstructure adjacent to focal cortical dysplasia: detection at diffusion-tensor MR imaging by using magnetoencephalographic dipole cluster localization. Radiology. 2009;251(1):206-215. PMID: 19221057. DOI: 10.1148/radiol.2511080808

26. Kossoff EH, Zupec-Kania BA, Auvin S, et al. Optimal clinical management of children receiving dietary therapies for epilepsy: Updated recommendations of the International Ketogenic Diet Study Group. Epilepsia Open. 2018;3(2):175-192. PMID: 29881797. DOI: 10.1002/epi4.12225

27. Loddenkemper T, Holland KD, Stanford LD, et al. Developmental outcome after epilepsy surgery in infancy. Pediatrics. 2007;119(5):930-935. PMID: 17473094. DOI: 10.1542/peds.2006-2530

---

Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists and current guidelines. Infantile spasms require urgent specialist paediatric neurology assessment and management.