Definition:

West syndrome, or infantile spasms (IS), is an infantile epileptic encephalopathy characterized by at least two of the following features: (a) clusters of flexion or extension epileptic spasms, (b) interictal electroencephalographic pattern (hypsarrhythmia), and (c) intellectual or neurodevelopmental disabilities. Most cases present at peak age of onset between 3 and 7 months, with 90% of patients presenting in the first year. The etiology of West syndrome is varied, ranging from structural, metabolic, unknown etiologies or genetic causes. Approximately 50% of cases have a prenatal cause, which includes central nervous system malformations, intrauterine insults, neurocutaneous syndromes such as tuberous sclerosis complex (TSC), metabolic disorders, and genetic syndromes such as Down's syndrome. The treatment options are hormonal therapy (adrenocorticotropic hormone ACTH, glucocorticosteroids) or the GABA aminotransferase inhibitor vigabatrin.