West syndrome is an uncommon to rare and serious form of infantile spasms (). It is named after the English physician, William James West (1793-1848), who first described it in an article published in The Lancet in 1841. Other names for it are “Generalized Flexion Epilepsy”, “Infantile Epileptic Encephalopathy”, “Infantile Myoclonic Encephalopathy”, “jackknife convulsions”, “Massive Myoclonia” and “Salaam spasms”. The name “infantile spasms” is used to describe both the seizure type and the syndrome, although not all infants with infantile spasms have West syndrome.
The syndrome is age-related, generally occurring between the third and the twelfth month, generally manifesting around the fifth month. There are various causes (“polyetiology”). The syndrome is often caused by an organic brain dysfunction whose origins may be prenatal, perinatal (caused during birth) or postnatal.