West Syndrome: Clinical Case Discussion & Key Learning Points
Model Case Presentation
Patient Demographics
Name: Master Arjun, Age: 7 months, Gender: Male, Informant: Mother (Reliable)
Chief Complaints
- Sudden jerking episodes of the body – 3 weeks
- Loss of previously attained developmental milestones – 2 weeks
- Increasing irritability and poor responsiveness – 2 weeks
History Summary
Mother describes brief, sudden episodes where the baby's trunk bends forward, arms fly out symmetrically, knees draw up, and the head nods — each lasting 1–2 seconds. The spasms occur in clusters of 10–20, especially just after waking from sleep. Each cluster lasts 5–10 minutes and the baby cries after the episode. The mother noticed that the baby, who had started social smiling and reaching for objects, has regressed — he no longer tracks faces, does not smile, and appears disinterested in surroundings.
No fever, no vomiting, no loss of consciousness during episodes. Episodes first noticed 3 weeks ago and are increasing in frequency. Parents initially mistook them for colic.
Birth history: Born at 38 weeks by emergency LSCS for fetal distress. Cried after resuscitation (delayed cry). Birth weight 2.9 kg. NICU admission for 5 days (perinatal asphyxia). Milestones were borderline prior to spasms. No family history of epilepsy. Non-consanguineous marriage.
Examination Summary
| Parameter | Finding | Significance |
|---|---|---|
| Weight | 6.2 kg | Borderline low (expected ~7 kg) |
| Head circumference | 42 cm (25th centile) | Normal |
| Tone | Hypotonia | Central nervous system involvement |
| Social smile | Absent | Developmental regression |
| Visual tracking | Poor | Cortical involvement |
| Fundus | Normal | Ash-leaf spots absent (rules out TSC on fundus) |
| Skin | No café-au-lait / ash-leaf spots / port-wine stain | Neurocutaneous syndromes less likely |
| DTRs | Brisk | Upper motor neuron involvement |
During examination: A cluster of 8 spasms observed — flexion of trunk, abduction of arms, brief upward gaze, followed by crying. Between spasms, baby appears dazed.
✅ Complete Diagnosis
West Syndrome (Infantile Epileptic Spasms Syndrome) — Symptomatic/Structural etiology (Hypoxic-Ischemic Encephalopathy) — Presenting with Epileptic Spasms in Clusters with Developmental Regression.
📝 History — Exam Q&A
West Syndrome is a severe epileptic encephalopathy of infancy characterized by a classical triad:
- Epileptic (infantile) spasms — brief, clustered axial seizures
- Hypsarrhythmia — chaotic, high-amplitude, disorganized interictal EEG pattern
- Developmental arrest or regression — loss of previously attained milestones
💡 Note — ILAE 2022
The ILAE now uses the broader term Infantile Epileptic Spasms Syndrome (IESS), which includes cases with spasms but without the full classical triad. West Syndrome is the most common subtype (~90% of IESS). The diagnosis can be made even if one feature of the triad is missing.
Dr. William James West described it in 1841 in a letter to The Lancet, based on his own infant son James, who suffered from repeated "bowings and relaxings" with progressive developmental regression. It is named in his honor.
- Incidence: ~1 in 2,400–5,500 live births
- Age of onset: 1–24 months; peak onset: 4–7 months (average 6–7 months)
- Sex: Slight male predominance
Each spasm is a brief (1–3 second) sudden axial contraction. They occur in clusters, most commonly on awakening from sleep. Three main types based on muscle groups involved:
| Type | Description |
|---|---|
| Flexor (most common) | "Jackknife/salaam" — sudden forward flexion of trunk, flexion of arms/legs, head nodding. Like a bow or salute. |
| Extensor | Sudden extension of trunk and extremities (opisthotonus-like) |
| Mixed (flexor-extensor) | Flexion of neck and trunk + extension of legs (or vice versa) |
Each cluster may contain 10–100+ spasms with brief intervals. Baby often cries after spasms (from discomfort/confusion, not pain).
The hypsarrhythmic EEG pattern is most prominent during NREM sleep (stages 2/3) and is greatly reduced or absent during REM sleep. During the transition from sleep to wakefulness (arousal), there is a sudden change in cortical state that triggers the clustered spasms. This sleep-wake transition is a classic triggering factor.
Ask specifically about loss of previously acquired skills:
- Did the baby used to smile socially? Does he/she still do it?
- Was the baby tracking faces/objects? Has that stopped?
- Did the baby recognize the mother's voice? Any change?
- Was baby vocalizing (cooing)? Has it reduced?
- Any change in interest in surroundings or play?
Regression (loss of attained milestones) is more alarming than simple delay and is a hallmark of epileptic encephalopathy.
Spasms may be subtle, especially early in the course. A brief head nod, a startle, or a forward jerk can easily be mistaken for: colic (abdominal pain posturing), gastroesophageal reflux (arching/flexing), or normal Moro reflex. The crying after a cluster reinforces the "colic" misdiagnosis. This leads to dangerous diagnostic delay — parents should be encouraged to record videos on smartphones to show the physician.
The ILAE classifies etiologies into Structural, Genetic, Metabolic, Infectious, Immune, and Unknown. Approximately 64% have an identifiable etiology; ~36% are unknown (previously called cryptogenic/idiopathic).
| Category | Examples |
|---|---|
| Structural (most common) | Hypoxic-Ischemic Encephalopathy (HIE) — #1 cause; cortical malformations (lissencephaly, polymicrogyria, pachygyria); tuberous sclerosis complex (TSC); porencephaly; hemorrhage; Sturge-Weber syndrome |
| Genetic | Trisomy 21 (Down syndrome) — most common chromosomal cause; ARX gene mutations; CDKL5; STXBP1; KCNQ2; TSC1/TSC2 |
| Metabolic | Pyridoxine (B6) dependency; phenylketonuria (PKU); non-ketotic hyperglycinemia; organic acidurias; mitochondrial disorders; biotinidase deficiency |
| Infectious | Congenital CMV, toxoplasmosis, rubella; meningitis/encephalitis sequelae |
| Unknown | ~36%; previously called "cryptogenic" — better prognosis |
💡 Mnemonic — Common Causes
HIE is the single most common cause (~25%). TSC is the most common genetic/neurocutaneous cause and has a special treatment implication (vigabatrin preferred as first line).
- Perinatal: LSCS for fetal distress, delayed cry, NICU admission → HIE
- Antenatal: Infections (TORCH), alcohol/drug exposure, maternal diabetes
- Family history: Epilepsy, neurocutaneous syndromes, consanguinity → genetic/metabolic
- Skin findings: Ash-leaf spots, shagreen patches → TSC; Port-wine stain → Sturge-Weber
- Milestones before spasms: Normal prior development → better prognosis; delayed prior → structural/genetic
- Prior seizures/neonatal encephalopathy
- Dietary history: Exclusive breastfeeding in maternal B12 deficiency → nutritional cause
| Feature | Symptomatic/Structural | Unknown (Cryptogenic) |
|---|---|---|
| Prior development | Often delayed or abnormal | Normal before spasms |
| Neuroimaging | Abnormal | Normal |
| Treatment response | Poorer | Better |
| Long-term intellect | ~71–85% impaired | 10–20% normal intelligence |
| Evolution to Lennox-Gastaut | Higher risk | Lower risk |
🩺 Examination — Exam Q&A
- Head circumference: Microcephaly (structural brain damage/malformations) or normal
- Skin:
- Ash-leaf hypopigmented macules (Wood's lamp) → Tuberous Sclerosis Complex (TSC)
- Shagreen patches, periungual fibromas, adenoma sebaceum → TSC
- Port-wine stain (trigeminal distribution) → Sturge-Weber
- Café-au-lait spots → Neurofibromatosis
- Dysmorphic features: Down syndrome facies (simian crease, epicanthic folds, flat nasal bridge)
- Nutritional status: Failure to thrive
- Tone: Hypotonia (most common finding in the encephalopathic infant)
- Reflexes: May be brisk (UMN), absent, or asymmetric depending on etiology
- Developmental assessment: Regression of social smile, visual tracking, vocalisation
- Eye: Poor visual tracking; may have nystagmus; fundus may show retinal lesions (CMV), retinal lacunae (Aicardi syndrome), or coloboma
- Fontanelle: Assess size and tension (raised ICP, hydrocephalus)
- During a cluster — observe: trunk flexion, arm abduction/adduction, brief upward eye deviation, followed by crying
Hypsarrhythmia (from Greek: "hyps" = high, "arrhythmia" = irregular rhythm) is the pathognomonic interictal EEG pattern of West Syndrome. It was first described by Gibbs and Gibbs in 1952.
EEG characteristics:
- Chaotic, disorganized, high-amplitude background
- Random multifocal spikes and sharp waves
- Intermixed high-amplitude slow waves (>200 μV)
- No organized rhythmic activity
- Asynchronous, asymmetric from hemisphere to hemisphere
It is most pronounced during NREM sleep and absent/greatly reduced during REM sleep.
💡 Ictal EEG pattern
During a spasm, the EEG shows a characteristic electrodecrement — a sudden flattening (suppression) of the background with superimposed low-amplitude fast activity, followed by a high-amplitude slow wave.
TSC is the most common single identifiable genetic cause of West Syndrome. Key skin signs:
| Sign | Description | Age of Appearance |
|---|---|---|
| Ash-leaf spots (hypomelanotic macules) | Oval hypopigmented patches; best seen under Wood's lamp (UV light) | Present at birth or early infancy |
| Shagreen patches | Thickened, orange-peel textured skin over lumbosacral area | Childhood |
| Adenoma sebaceum (angiofibromas) | Red papules over nasal bridge and cheeks (butterfly distribution) | Age 3–5 years onward |
| Periungual / subungual fibromas | Fibrous growths around nail beds (Koenen's tumors) | Adolescence onward |
| Café-au-lait spots | Flat hyperpigmented spots (less specific for TSC) | Infancy |
🚨 Key Point
In an infant with West Syndrome, always examine under Wood's lamp for ash-leaf spots — the earliest and most reliable cutaneous marker of TSC, and the skin examination may be entirely normal at this age without it.
| Mimic | Distinguishing Feature |
|---|---|
| Colic | No clustering; crying is primary event; no developmental regression; no EEG changes |
| GER (reflux) | Triggered by feeding; Sandifer syndrome — dystonic posturing during feeds |
| Benign neonatal sleep myoclonus | Only during sleep, disappears on waking; EEG normal |
| Startle response (Moro reflex) | Triggered by external stimulus; no clustering; disappears by 4–5 months |
| Shuddering attacks | Brief shivering; no regression; normal EEG; family history |
| Myoclonic epilepsies (Dravet syndrome, myoclonic-astatic epilepsy) | Different EEG patterns; different clinical context; no hypsarrhythmia |
| Ohtahara syndrome (EIEE) | Onset in neonates; burst-suppression EEG; tonic spasms |
A 6–7 month-old with West Syndrome will typically show regression or loss of:
- Social smile (expected by 6 weeks) — may be lost
- Visual tracking — decreased or absent
- Vocalisation/cooing — reduced
- Head control — may regress
- Interest in surroundings — withdrawn, blank appearance, "autistic-like"
The child may appear vacant, hypotonic, and socially withdrawn between spasms — this is the epileptic encephalopathy itself, not just the post-ictal state.
🔬 Investigations — Exam Q&A
Video-EEG (prolonged awake and asleep, preferably 24-hour inpatient video-EEG) is the gold standard. It serves to:
- Confirm hypsarrhythmia (interictal pattern)
- Document electrodecrement during spasms (ictal correlation)
- Rule out non-epileptic mimics
- Detect focal abnormalities suggesting structural etiology
- Assess treatment response (resolution of hypsarrhythmia)
💡 Key point
A routine short awake EEG may be sufficient for initial diagnosis, but a sleep EEG or overnight video-EEG is recommended as hypsarrhythmia is best seen in NREM sleep. If spasms are suspected but a single EEG is normal, repeat EEG (especially during sleep) is required.
MRI brain (with gadolinium if needed) is the preferred neuroimaging — it identifies structural causes and guides surgical decisions. CT brain is inferior but faster and used if MRI unavailable.
MRI findings by etiology:
- HIE: Periventricular leukomalacia, cortical atrophy, basal ganglia changes
- TSC: Cortical/subcortical tubers (hypointense on T1, hyperintense on T2), subependymal nodules
- Cortical malformations: Lissencephaly, polymicrogyria, focal cortical dysplasia
- Sturge-Weber: Unilateral cerebral atrophy, pial enhancement, choroid plexus enlargement
- Unknown (cryptogenic): Normal MRI → better prognosis
Since metabolic causes are treatable (e.g., pyridoxine-responsive epilepsy, PKU, biotinidase deficiency), these must be ruled out:
- Blood: Glucose, lactate, ammonia, amino acids (plasma amino acid chromatography), urine organic acids, biotinidase activity
- CSF: Glucose, lactate, amino acids (especially glycine), neurotransmitters (if GLUT1 deficiency or serine synthesis disorder suspected)
- Pyridoxine trial: IV pyridoxine (100 mg) during EEG — EEG suppression confirms pyridoxine-dependent epilepsy
- Thyroid function, serum B12 and homocysteine: Especially in exclusively breastfed infants of vegetarian/vegan mothers
- TORCH serology: CMV, toxoplasma — for congenital infections
- Chromosomal microarray + Gene panel (NGS): For genetic causes (TSC1/TSC2, ARX, CDKL5, STXBP1)
| Phase | EEG Finding |
|---|---|
| Interictal (between spasms) | Hypsarrhythmia — chaotic, high-amplitude (>200 μV), disorganized mixture of slow waves and multifocal spikes; asynchronous |
| Ictal (during a single spasm) | Electrodecrement — sudden high-amplitude slow wave followed by diffuse voltage suppression (flattening) with superimposed low-amplitude fast activity (beta); this is the pathognomonic ictal pattern |
| During a cluster | Repeated electrodecrements separated by brief high-amplitude bursts |
FDG-PET (Positron Emission Tomography) and SPECT are used in evaluation for epilepsy surgery candidacy:
- PET identifies focal areas of hypometabolism between spasms (ictal hypermetabolism)
- Helps identify focal cortical dysplasia or TSC tubers not visible on MRI
- Useful when MRI is normal but focal EEG abnormality is present
- Not routine — reserved for refractory cases being evaluated for surgical resection
EEG is repeated 2 weeks after starting treatment to assess response. A favorable response is defined as electroclinical remission:
- Clinical: Complete cessation of spasms
- EEG: Resolution of hypsarrhythmia (normalization or significant improvement of background)
If spasms persist OR hypsarrhythmia persists at 2 weeks, treatment should be escalated or changed without delay. A child may be clinically spasm-free but still have residual hypsarrhythmia — this is a partial response and requires further treatment, as continued encephalopathy worsens developmental outcome.
💊 Management — Exam Q&A
First-line treatments are hormonal therapy and vigabatrin:
- Hormonal therapy:
- ACTH (Adrenocorticotropic Hormone) — intramuscular, synthetic (Synacthen/tetracosactide) or natural. Dose: 20–40 IU/day (or 150 IU/m²/day) for 2 weeks, then taper. More effective for spasm cessation in TSC-unrelated cases.
- High-dose oral Prednisolone — 8 mg/kg/day (max 60 mg/day) for 2 weeks, then taper. Comparable efficacy to ACTH; easier to administer; widely used globally due to cost and logistical advantages of ACTH.
- Vigabatrin — GABA transaminase inhibitor. Dose: 100–150 mg/kg/day in 2 divided doses. Drug of choice for TSC-related West Syndrome — achieves remission in up to 95% of TSC cases.
✅ UKISS Trial (2004–2005) and ICISS Trial (2017)
UKISS: Hormonal therapy (ACTH or prednisolone) was superior to vigabatrin alone for cessation of spasms at 14 days in non-TSC cases. ICISS: Combination of hormonal therapy + vigabatrin was more effective and faster than hormonal therapy alone, and is now preferred by many centres.
Every day of untreated hypsarrhythmia worsens the epileptic encephalopathy. Prolonged exposure causes:
- Ongoing developmental regression and cognitive injury
- Higher risk of progression to Lennox-Gastaut Syndrome
- Higher risk of autism spectrum disorder
- Increased seizure burden and drug resistance
Studies show that a shorter lag time from spasm onset to treatment is associated with better neurodevelopmental outcomes. If West Syndrome is suspected, EEG should be arranged within 24 hours and treatment started urgently after confirmation.
- Hypertension — must monitor BP regularly (common with ACTH; all patients)
- Immunosuppression — susceptibility to infections; avoid live vaccines during treatment
- Hyperglycemia — monitor blood sugar
- Electrolyte disturbances — hypokalemia, hyponatremia
- Cushing's features — weight gain, moon face, irritability, gastric irritation
- Cerebral atrophy — transient, reversible, seen on imaging with prolonged ACTH use
- Hypertrophic cardiomyopathy — rare but serious; cardiology consultation before starting ACTH is recommended
- Behavioral changes — severe irritability, sleep disturbance
- Visual field defects (retinal toxicity) — the most important long-term side effect; irreversible bilateral concentric visual field constriction. Occurs in ~30–40% of adults; less documented in infants. Requires electroretinogram (ERG) monitoring.
- Vigabatrin-associated brain abnormalities on MRI (VABAM) — T2/FLAIR hyperintensities in basal ganglia, thalamus, brainstem, dentate nuclei; seen in 22–32% of infants; usually asymptomatic and may resolve; significance is debated.
- Sedation, hypotonia
- MRI changes are more common when vigabatrin is combined with ACTH (fulminant encephalopathy risk — rare but reported)
- Switch to the alternative first-line agent (e.g., if vigabatrin was used first, add/switch to ACTH or prednisolone — and vice versa)
- Combination hormonal therapy + vigabatrin (ICISS protocol)
- Ketogenic diet (KD) — high fat, low carbohydrate diet; evidence shows >50% seizure reduction in ~40–63% of refractory cases; requires dietitian supervision
- Sodium valproate — oral; useful particularly in Down syndrome-associated West syndrome
- Nitrazepam — a benzodiazepine; used as adjunct
- Topiramate, zonisamide, lamotrigine — used in refractory cases
- Pyridoxine (Vitamin B6) — trial given in all new cases (especially in Japan where pyridoxine-responsive epilepsy is prevalent); 100–500 mg/day IV or oral during EEG monitoring
Surgery is considered in refractory West Syndrome with a focal structural lesion:
- Focal cortical dysplasia (FCD) — resection of epileptogenic zone
- Cortical tubers in TSC — identification of "epileptogenic tuber" by PET/EEG, followed by tuberectomy
- Hemimegalencephaly — hemispherotomy
- Porencephalic cyst, Sturge-Weber — resection or hemispherotomy
Early surgery (even in infancy) in eligible candidates can abolish spasms and prevent further developmental damage. Pre-surgical evaluation includes video-EEG, MRI, PET/SPECT, and neuropsychological assessment.
Generally poor, but depends heavily on etiology:
- Intellectual disability: ~71–85% of all children; only 10–20% of cryptogenic cases achieve normal intelligence
- Other epilepsy types: 50–70% develop additional seizure types after spasms resolve
- Lennox-Gastaut Syndrome: ~23–50% evolve to LGS (the most feared evolution)
- Autism spectrum disorder: A significant proportion, especially in TSC and Down syndrome
- Mortality: ~5% in infancy; long-term mortality elevated
Favorable prognostic factors: Unknown/cryptogenic etiology, normal development before spasm onset, age of onset >4 months, normal MRI, no asymmetric EEG, early and effective treatment, rapid electroclinical remission.
Unfavorable prognostic factors: Symptomatic etiology (especially HIE, malformations), developmental delay before spasms, delayed diagnosis/treatment, refractory to multiple therapies, TSC with multiple tubers.
Lennox-Gastaut Syndrome (LGS) is a severe childhood epileptic encephalopathy characterized by:
- Multiple seizure types (tonic, atonic, atypical absence)
- Diffuse slow spike-and-wave on EEG (<2.5 Hz)
- Intellectual disability
West Syndrome evolves to LGS in 23–50% of cases — typically the child's spasms cease by 2–4 years but are replaced by tonic/atonic seizures and slow spike-wave on EEG. Both syndromes are severe epileptic encephalopathies of early childhood and may represent an age-dependent continuum of the same underlying epileptogenic process. Early, effective treatment of West Syndrome may reduce the risk of LGS evolution.
- Vigabatrin is the drug of choice (first-line) for TSC-associated West Syndrome — response rate up to 95%
- If vigabatrin fails, mTOR inhibitors (everolimus, sirolimus) can be used — TSC is caused by TSC1/TSC2 mutations leading to mTOR pathway hyperactivation; mTOR inhibitors specifically target this pathway
- Regular monitoring: Ophthalmology (retinal astrocytic hamartomas, ERG for vigabatrin toxicity), cardiac (rhabdomyomas), renal (angiomyolipomas)
- Genetic testing — TSC1/TSC2 mutational analysis
- EEG-guided identification of the epileptogenic tuber for possible surgical resection
🔭 Recent Advances — Exam Q&A
In 2022, the ILAE proposed replacing "West Syndrome" with the broader term Infantile Epileptic Spasms Syndrome (IESS). Rationale:
- Some infants have epileptic spasms without the full classical triad (spasms alone, or spasms + developmental regression without hypsarrhythmia)
- Strict adherence to the full triad can lead to delayed diagnosis and treatment
- IESS encourages broader recognition and prompt treatment
West Syndrome (classical triad) remains a subtype within IESS (~90% of cases). The term "infantile spasms" now refers to the seizure type, not the syndrome.
The ketogenic diet (KD) is a high-fat, low-carbohydrate, adequate-protein diet that produces ketosis, which has anticonvulsant effects:
- Indication: Refractory West Syndrome after failure of first and second-line medications
- Efficacy: >90% seizure reduction in ~40–63% of refractory cases; ~37% achieve spasm freedom at 6 months
- Special role: First-line in GLUT1 deficiency and pyruvate dehydrogenase deficiency (metabolic indications)
- Adverse effects: GI symptoms, constipation, renal calculi, growth retardation, dyslipidaemia, hypoglycemia
- Modified versions: Modified Atkins diet and low glycaemic index treatment are easier to implement
Tuberous Sclerosis Complex (TSC) results from mutations in TSC1 (hamartin) or TSC2 (tuberin), leading to hyperactivation of the mTOR (mammalian target of rapamycin) pathway → uncontrolled cell growth → cortical tubers → epilepsy.
- Everolimus (mTOR inhibitor) — FDA approved for TSC-associated seizures in children ≥2 years (EXIST-3 trial showed significant seizure reduction)
- Sirolimus (Rapamycin) — also used in TSC; suppresses tuber growth and reduces seizures
- These agents represent precision/targeted therapy for a specific genetic cause of West Syndrome
- Also used for renal angiomyolipomas, pulmonary lymphangioleiomyomatosis, and SEGA (subependymal giant cell astrocytoma) in TSC
The ICISS (International Collaborative Infantile Spasms Study) trial (Lancet Neurology, 2017) was a multicentre RCT comparing:
- Hormonal therapy alone (ACTH or prednisolone) vs.
- Hormonal therapy + Vigabatrin (combination)
Results: Combination therapy (hormonal + vigabatrin) achieved significantly better electroclinical remission (cessation of spasms + resolution of hypsarrhythmia) at 14 days — 72% vs 57% for hormonal therapy alone. Combination therapy is now preferred by many centres for initial treatment of West Syndrome, especially for rapidly achieving remission to protect neurodevelopment.
Advancing genomics has dramatically improved etiological diagnosis. A significant proportion of "cryptogenic/unknown" cases now have a genetic diagnosis:
- Chromosomal microarray — detects copy number variants (CNVs); identifies chromosomal deletions/duplications
- Next-Generation Sequencing (NGS) gene panel or Whole Exome Sequencing (WES) — identifies single gene mutations: TSC1/TSC2, ARX (X-linked; males), CDKL5 (X-linked; females), STXBP1, KCNQ2, GRIN2A, GRIN2B, etc.
- Importance of genetic diagnosis:
- Guides precision therapy (e.g., vigabatrin for TSC; mTOR inhibitors; pyridoxine for B6-dependent epilepsy)
- Counseling for recurrence risk and prenatal diagnosis
- Avoids unnecessary further workup
The exact mechanism is not fully understood, but the leading hypothesis involves the CRH (Corticotropin-Releasing Hormone) theory:
- In the immature, stressed brain, excessive CRH is released from limbic and hypothalamic neurons
- CRH is a powerful proconvulsant in the immature brain (via CRH receptors on hippocampal and cortical neurons)
- ACTH acts on the adrenal gland → cortisol, which suppresses hypothalamic CRH production via negative feedback → reduces seizure threshold
- Additionally, ACTH may have direct brain effects via melanocortin receptors (independent of adrenal axis)
- This explains why adrenal suppression by exogenous steroids (prednisolone) also works — both suppress CRH-mediated hyperexcitability
Home smartphone video recording is now officially recommended (endorsed by the Child Neurology Society) as an essential tool in evaluation of infantile spasms:
- Parents record the spasm episode on a smartphone during an event
- The video is shared with the physician before or at the consultation
- Allows the neurologist to distinguish spasms from mimics (colic, GER, Moro reflex) without waiting for an in-office episode
- Enables faster diagnosis, EEG referral, and treatment initiation
- Particularly important as spasms occur at home (especially on awakening) and rarely during a clinic visit
⚡ Key Points — Quick Revision
One-Liners for Exam
- Classical Triad: Epileptic spasms + Hypsarrhythmia (EEG) + Developmental regression
- New ILAE term: Infantile Epileptic Spasms Syndrome (IESS) — broader than West Syndrome
- Peak age of onset: 4–7 months (range 1–24 months)
- Most common etiology: HIE (Hypoxic-Ischemic Encephalopathy) ~25%
- Most common genetic/neurocutaneous cause: Tuberous Sclerosis Complex (TSC)
- Spasms occur in clusters: Typically on awakening from sleep
- Type of spasm: Flexor (most common) — jackknife/salaam — trunk forward, arms out, legs up
- Hypsarrhythmia: High-amplitude, chaotic, disorganized, multifocal spikes — interictal pattern; most prominent in NREM sleep
- Ictal EEG: Electrodecrement — sudden voltage suppression with fast activity
- Gold standard investigation: Video-EEG (preferably overnight/24-hour)
- Neuroimaging: MRI brain (identifies structural causes)
- First-line treatment (non-TSC): ACTH or high-dose prednisolone (hormonal therapy); vigabatrin as alternative
- First-line treatment (TSC): Vigabatrin (drug of choice, ~95% response rate)
- ICISS trial: Combination hormonal + vigabatrin → superior electroclinical remission (72% vs 57% at 14 days)
- Vigabatrin main SE: Irreversible visual field defects (retinal toxicity) — monitor with ERG
- ACTH main SEs: Hypertension, immunosuppression, hyperglycemia, irritability, Cushingoid features
- Ketogenic diet: Second/third-line for refractory cases; first-line for GLUT1 deficiency
- Evolution: 23–50% progress to Lennox-Gastaut Syndrome
- Cryptogenic prognosis: 10–20% have normal intellect; treated early
- Symptomatic prognosis: ~71–85% have intellectual disability
- mTOR inhibitors: Everolimus/sirolimus for TSC-related West Syndrome (precision therapy)
- Skin sign to never miss: Ash-leaf spots (hypopigmented macules) on Wood's lamp examination → TSC
- Common misdiagnosis: Colic, GER → home smartphone video recording is recommended to aid early diagnosis
- Pyridoxine trial: Always consider in new-onset cases — treatable cause (pyridoxine-dependent epilepsy)
🚨 Exam Traps
- Spasms occur in clusters — not isolated jerks. A single spasm is easy to miss; the cluster is the alarm.
- Hypsarrhythmia is an interictal pattern; the ictal pattern is electrodecrement.
- Vigabatrin is first-line in TSC, not in non-TSC cases (where hormonal therapy is superior short-term).
- A normal MRI does not rule out West Syndrome; it suggests cryptogenic etiology (better prognosis).
- Cessation of spasms ≠ treatment success — hypsarrhythmia must also resolve on EEG for a complete electroclinical response.