West syndrome, also called infantile spasms, is a rare form of epilepsy in infants and children that starts in the first year of life, usually between 4 and 8 months old. It is characterized by spasms, arrest or even regression of the psychomotor development of the baby and abnormal brain activity. The prognosis is very variable and depends on the underlying causes of the spasms, which can be multiple. It can cause serious motor and intellectual sequelae and progress to other forms of epilepsy.

Spasms are the first dramatic manifestations of the syndrome, although the baby’s altered behavior may have preceded them shortly. They usually occur between 3 and 8 months, but in rare cases the disease can be earlier or later. Very brief muscle contractions (one to two seconds) isolated, most often upon awakening or after eating, gradually give way to bursts of spasms that can last for 20 minutes. The eyes are sometimes rolled back at the time of the seizure.

Spasms are only visible signs of a permanent dysfunction in brain activity that damages it, resulting in delayed psychomotor development. Thus, the appearance of spasms is accompanied by the stagnation or even the regression of psychomotor capacities already acquired: interactions such as smiles, gripping and manipulation of objects … Electroencephalography reveals chaotic brain waves which are referred to as hypsarrhythmia.

Spasms are due to faulty activity of neurons releasing sudden and abnormal electrical discharges. Many underlying disorders can be the cause of West syndrome and can be identified in at least three-quarters of affected children: birth trauma, brain malformation, infection, metabolic disease, genetic defect ( Down syndrome, for example), neuro-cutaneous disorders (Bourneville’s disease). The latter is the most common disorder responsible for West syndrome. The remaining cases are said to be “idiopathic” because they occur for no apparent reason, or “cryptogenic”, that is to say probably linked to an anomaly that we do not know how to determine.

West’s syndrome is not contagious. It affects boys a little more frequently than girls. This is because one of the causes of the disease is linked to a genetic defect linked to the X chromosome affecting men more often than women.

The disease cannot be detected before the first symptoms appear. The standard treatment is to take an anti-epileptic drug by mouth daily (Vigabatrin is most commonly prescribed). It can be combined with corticosteroids. Surgery can intervene, but quite exceptionally, when the syndrome is linked to localized brain lesions, their removal can improve the child’s condition.

The prognosis is very variable and depends on the underlying causes of the syndrome. It is all the better when the infant is old at the time of the onset of the first spasms, the treatment is early and the syndrome is idiopathic or cryptogenic. 80% of affected children have sequelae that are sometimes irreversible and more or less serious: psychomotor disorders (delay in speaking, walking, etc.) and behavior (withdrawal into oneself, hyperactivity, attention deficit, etc.). (1) Children with West syndrome are frequently prone to subsequent epileptic disease, such as Lennox-Gastaut syndrome (SLG).