West Syndrome

Overview

West syndrome is a rare but severe form of early childhood epilepsy, also known as infantile spasms. It is characterized by a triad of symptoms: epileptic spasms (sudden, brief muscle contractions), a specific abnormal brain wave pattern on electroencephalogram (EEG) called hypsarrhythmia, and developmental regression or delay. The condition typically begins between 3 and 12 months of age and requires urgent medical attention due to its potential to cause long-term neurodevelopmental impairments if not treated promptly.

West syndrome was first described by Dr. William James West in the 19th century, who observed the symptoms in his own child. It is classified under the broader category of epileptic encephalopathies, where seizures themselves contribute to cognitive and developmental deterioration.

Causes

West syndrome can be caused by a wide range of underlying conditions, which are typically grouped into three categories: symptomatic, cryptogenic, and idiopathic.

Symptomatic (Secondary) West Syndrome

• Brain malformations: Such as lissencephaly, hemimegalencephaly, or agenesis of the corpus callosum.

• Perinatal brain injury: Due to birth asphyxia, prematurity, or intraventricular hemorrhage.

• Metabolic disorders: Including mitochondrial disease or urea cycle disorders.

• Genetic syndromes: Such as tuberous sclerosis complex (TSC), Down syndrome, or CDKL5-related disorders.

• Infections: Prenatal infections like cytomegalovirus (CMV) or postnatal encephalitis.

Cryptogenic West Syndrome

In these cases, a cause is suspected based on clinical signs but cannot be confirmed through available investigations.

Idiopathic West Syndrome

When no identifiable cause is found and the child had normal development prior to the onset of spasms. These cases often have a better prognosis.

Symptoms

The hallmark symptom of West syndrome is epileptic spasms. Other features develop as the condition progresses or based on the underlying cause.

Primary Symptoms

• Infantile spasms: Sudden, brief muscle contractions that typically involve the neck, trunk, and limbs. They often occur in clusters, especially upon waking or falling asleep.

• Developmental regression: Loss of previously acquired skills, such as smiling, sitting, or babbling.

• Hypsarrhythmia: A chaotic, disorganized EEG pattern that is a diagnostic hallmark of the condition.

Other Possible Features

• Feeding difficulties

• Low muscle tone or stiffness

• Excessive irritability or lethargy

• Delayed milestones

• Seizures evolving into other types: Over time, spasms may be replaced by other seizure types (Lennox-Gastaut syndrome).

Diagnosis

Diagnosis of West syndrome requires a combination of clinical observation, EEG findings, and evaluation of potential underlying causes. Key diagnostic steps include:

• Clinical evaluation: History of spasms, developmental delay or regression, and family history of neurological disorders.

• Electroencephalogram (EEG): Shows a characteristic pattern called hypsarrhythmia—high-voltage, disorganized background activity with multifocal spikes.

• Neuroimaging: MRI of the brain to identify structural abnormalities or evidence of past injury.

• Metabolic and genetic testing: Blood and urine tests may be ordered to detect inborn errors of metabolism or syndromic causes.

• Developmental assessments: To document the extent of cognitive or motor delays.

Treatment

Treatment of West syndrome aims to control spasms, normalize the EEG, and minimize developmental impairment. Early, aggressive intervention is crucial. Common treatment strategies include:

First-Line Therapies

• Adrenocorticotropic hormone (ACTH): One of the most effective treatments, typically given as an intramuscular injection over several weeks.

• Oral corticosteroids: Such as prednisone, used when ACTH is not available or contraindicated.

• Vigabatrin: Particularly effective in patients with tuberous sclerosis complex. Administered orally.

Other Antiepileptic Medications

• Valproic acid

• Topiramate

• Levetiracetam

Dietary Therapy

• Ketogenic diet: A high-fat, low-carbohydrate diet that may help reduce seizure frequency when medications are ineffective.

Supportive Therapies

• Physical and occupational therapy: To improve motor skills and coordination.

• Speech therapy: For language development delays.

• Developmental and behavioral support: Early intervention services are essential for long-term outcomes.

Prognosis

The prognosis for children with West syndrome varies widely and depends on the underlying cause and response to treatment. General prognostic considerations include:

• Better prognosis: Seen in idiopathic cases or when spasms are controlled quickly and EEG normalizes.

• Poorer outcomes: Associated with symptomatic cases, delayed treatment, or persistent hypsarrhythmia.

• Risk of progression: Many children may go on to develop other seizure disorders like Lennox-Gastaut syndrome and suffer long-term cognitive impairment.

• Developmental outcomes: Most children have some degree of intellectual disability or developmental delay, though early and aggressive therapy can improve functional outcomes.

Regular follow-up with a pediatric neurologist, comprehensive therapy, and family support are crucial for managing the condition and maximizing the child’s quality of life.