What is the recommended treatment for an infant diagnosed with West syndrome?

West Syndrome Treatment

For an infant diagnosed with West syndrome, initiate treatment immediately with either vigabatrin (50-150 mg/kg/day) or ACTH/corticosteroids as first-line therapy, with the choice guided by etiology—vigabatrin is preferred for tuberous sclerosis, while ACTH may be superior for other etiologies. 1, 2, 3

Immediate First-Line Treatment Options

Vigabatrin

• Start at 50-150 mg/kg/day divided into two daily doses 1, 2
• Assess response within 15 days; if spasms persist at 150 mg/kg/day, consider switching to ACTH 3
• Critical monitoring requirement: Baseline ophthalmologic examination before initiation, then periodic vision testing throughout treatment due to retinal toxicity risk (occurs in 21-34% of infants, especially with treatment >6 months) 1, 2
• Mandatory enrollment in the Vigabatrin REMS Program before dispensing 1
• Obtain baseline and periodic brain MRI, as abnormal signal changes (increased T2 signal in thalamus, basal ganglia, brainstem, cerebellum) occur in approximately 22% of vigabatrin-treated infants versus 4% with other therapies 1

ACTH or Corticosteroids

• Low-dose ACTH is as effective as high-dose for short-term treatment (typically 2 weeks followed by tapering) 2
• Oral prednisolone 40-60 mg/day for 14 days is an effective and well-tolerated alternative 2
• Monitor closely for Cushing syndrome (occurs universally with ACTH), arterial hypertension, and rare but serious complications including gastric bleeding 3
• ACTH may be added if vigabatrin fails to control spasms within 15 days 3

Treatment Selection Algorithm

For cryptogenic/idiopathic cases:

• Either vigabatrin or ACTH/corticosteroids are appropriate first-line options 2, 3
• Vigabatrin may be preferred to avoid systemic corticosteroid side effects 3

For symptomatic cases with identified structural etiology:

• Consider ACTH/corticosteroids as initial therapy 2, 3
• Exception: If tuberous sclerosis is the cause, vigabatrin is the preferred first-line agent 2

For cases with focal cortical dysplasia:

• Early surgical evaluation should be considered alongside medical management, as these patients may have partial seizures preceding or accompanying infantile spasms 4

Critical Timing Considerations

• Treatment lag (time from spasm onset to treatment initiation) should be minimized, though its impact on prognosis remains controversial 5
• Mean age at spasm onset is typically 5.8 months, with diagnosis/treatment around 7.2 months 3
• Assess treatment response within 2-4 weeks; if no improvement, switch to alternative first-line therapy 3, 6

Essential Diagnostic Workup Before Treatment

• Brain MRI is the highest yield initial study to determine etiology and guide treatment choices 6, 4
• EEG to confirm hypsarrhythmia pattern 2, 6
• Genetic and metabolic testing to identify treatable causes 2, 6
• Follow-up MRI may be necessary to detect delayed myelination not visible at typical onset ages 4
• PET scanning can help differentiate cryptogenic cases and predict seizure/psychomotor prognosis 4

Monitoring and Follow-Up

For vigabatrin:

• Ophthalmologic examinations at baseline and periodically throughout treatment 1, 2
• Brain MRI surveillance for infants, as signal abnormalities may occur (though often reversible with discontinuation) 1
• Monitor for suicidal thoughts/behavior (rare but reported with all antiepileptic drugs) 1

For ACTH/corticosteroids:

• Blood pressure monitoring for hypertension 3
• Watch for signs of Cushing syndrome 3
• Monitor for gastrointestinal complications 3

Second-Line and Alternative Therapies

• Ketogenic diet may be useful if first-line medications fail 6
• Other antiepileptic medications can be considered, though evidence is limited 6
• Combination therapy (vigabatrin plus ACTH) may be attempted if monotherapy fails 3

Common Pitfalls to Avoid

• Do not delay treatment while awaiting complete diagnostic workup if West syndrome diagnosis is clinically evident 2, 6
• Do not continue vigabatrin beyond 6 months without compelling reason, as retinal toxicity risk increases significantly 2
• Do not abruptly discontinue vigabatrin, as this can precipitate status epilepticus; taper according to prescriber guidance 1
• Do not assume normal outcome even with spasm control—the underlying etiology (symptomatic vs. cryptogenic/idiopathic) and presence of pre-existing developmental abnormalities are the strongest predictors of long-term neurodevelopmental outcome 3, 5
• Do not overlook visual field monitoring with vigabatrin—retinal toxicity can be avoided with careful funduscopic follow-up 3

Prognostic Counseling

• Cryptogenic/idiopathic cases have significantly better outcomes (normal development possible in up to 50% if treated appropriately) compared to symptomatic cases 3, 6
• Symptomatic cases, particularly those with hypoxic-ischemic encephalopathy or cortical malformations, have poor prognosis with 76% developing severe psychomotor retardation and 43% developing ongoing epilepsy 3
• Mortality rate is approximately 7% in symptomatic cases 3
• Lennox-Gastaut syndrome develops in approximately 14% of symptomatic cases 3