Infantile epileptic spasms syndrome

Infantile Epileptic Spasms Syndrome (IESS), also known as West Syndrome, is a severe form of epilepsy that typically begins in infancy. It is characterized by a specific type of seizure known as an epileptic spasm, developmental regression, and a distinctive electroencephalogram (EEG) pattern called hypsarrhythmia.

Clinical Presentation

Infantile Epileptic Spasms Syndrome usually presents between 3 to 12 months of age. The hallmark of the syndrome is the presence of epileptic spasms, which are sudden, brief contractions of the muscles that can affect the head, trunk, and limbs. These spasms often occur in clusters, especially upon waking.

Symptoms

• Epileptic spasms: Sudden flexion, extension, or mixed flexion-extension of the neck, trunk, and extremities.
• Developmental regression: Loss of previously acquired skills, such as sitting or babbling.
• Hypsarrhythmia: A chaotic and disorganized EEG pattern.

Etiology

The causes of Infantile Epileptic Spasms Syndrome are diverse and can be classified into symptomatic, cryptogenic, and idiopathic categories.

• Symptomatic: Due to identifiable brain lesions or metabolic disorders.
• Cryptogenic: No clear cause is identified, but a symptomatic cause is suspected.
• Idiopathic: No identifiable cause, and the child is otherwise normal.

Common causes include tuberous sclerosis, Down syndrome, and perinatal asphyxia.

Diagnosis

Diagnosis of IESS is based on clinical presentation, EEG findings, and neuroimaging.

• Electroencephalogram (EEG): The presence of hypsarrhythmia is a key diagnostic feature.
• Neuroimaging: MRI or CT scans may reveal structural brain abnormalities.
• Genetic Testing: May be conducted to identify underlying genetic causes.

Treatment

The primary goal of treatment is to control seizures and address developmental issues. Treatment options include:

• Adrenocorticotropic Hormone (ACTH): Often used as a first-line treatment.
• Vigabatrin: Particularly effective in cases associated with tuberous sclerosis.
• Antiepileptic drugs (AEDs): Such as valproic acid or topiramate.
• Ketogenic diet: May be considered in refractory cases.
• Surgery: In cases with focal brain lesions, surgical intervention may be an option.

Prognosis

The prognosis for children with Infantile Epileptic Spasms Syndrome varies widely and depends on the underlying cause. Early diagnosis and treatment are crucial for improving outcomes. Many children with IESS may develop other types of epilepsy or experience developmental delays.

Research and Future Directions

Ongoing research aims to better understand the genetic and molecular mechanisms underlying IESS, which may lead to more targeted therapies. Advances in neuroimaging and genetic testing continue to improve diagnostic accuracy and treatment strategies.

See Also

• Epilepsy
• Tuberous sclerosis
• Hypsarrhythmia
• Developmental delay

References

• Lux, A. L., & Osborne, J. P. (2004). A proposal for case definitions and outcome measures in studies of infantile spasms and West syndrome: Consensus statement of the West Delphi group. Epilepsia, 45(11), 1416-1428.
• Riikonen, R. (2014). Recent advances in the pharmacotherapy of infantile spasms. CNS Drugs, 28(4), 279-290.