Infantile epileptic spasms syndrome (IESS) previously known as West syndrome needs the inclusion of epileptic spasms for diagnosis. Epileptic spasms (also known as infantile spasms) may also occur outside of a syndrome (that is, in the absence of hypsarrhythmia and cognitive regression) - notably in association with a severe brain disorder such as lissencephaly. IESS is an epileptic encephalopathy, a childhood epilepsy syndrome arising during infancy. It can often arise as a complication of various other medical conditions. It is clinically defined by the occurrence of the characteristic epileptic spasms, episodes of clusters of tonic spasms of the axial and limb musculature. Such spasms are found in association with characteristic abnormal electroencephalogram pattern findings (hypsarrhythmia), and cognitive delay or deterioration. The peak age of onset is 4-6 months of age, with 90% of cases presenting during the first year of life. The spasms are usually resistant to conventional antiepileptics. They may persist beyond infancy, or, rarely, commence only later in childhood. Many individuals with the syndrome go on to develop other forms of epilepsy later in life (notably Lennox–Gastaut syndrome), and persisting neurodevelopmental deficits are common; notably, up to about a third of children are subsequently diagnosed with autism. Pharmacotherapy consists of either adrenocorticotropic hormone (ACTH) or glucocorticoids (prednisone), or vigabatrin. Ketogenic diet may be effective as second-line therapy for treatment-resistant cases. Neurosurgery may be indicated in certain cases. Epileptic spasms are commonly classified as symptomatic when a potential cause can be identified, or as cryptogenic if not (though these designations are used inconsistently). A specific cause can be identified in ~70-75%. Any condition that may cause cerebral insult may give rise to IESS. Causes range from genetic disorders, infections, congenital malformations, malnutrition, to brain trauma. The most commonly identified common cause is tuberous sclerosis complex. Cryptogenic cases entail a more favourable prognosis overall. West syndrome is named for the English physician William James West who was first to describe the condition in an article in The Lancet in 1841 based on observations of the condition in his son.
Signs and symptoms
Epileptic spasms Epileptic spasms are a seizure type characteristic for the first year of life. The spasms are typically resistant to conventional pharmacotherapy. There are many episodes per day. Episodes may take place after waking or feeding, or less often before falling asleep. Episode duration, intensity, and muscle groups affected are variable. Mild spasms may involve mere nodding, muscle twitching or eye movements, whereas powerful spasms may result in the infant's body violently bending over (the so-called "salaam" or "jackknife" movements). Individual spasms typically last only seconds, but episodes may last over 20 minutes. An episode is typically followed by exhaustion; episodes are typically followed by over a minute of motionlessness and diminished responsiveness. The spasms present as episodes of brisk (0.2-2s) neck flexions-extensions and upper limp abductions-adductions, lower limb extension, and trunk musculature contractions, accompanied by upward deviation of the eyes. Nevertheless, individual muscle groups (abdominal, shoulder, neck) may be involved. Most often, there is simultaneous contraction of both flexors and extensors, followed by flexor spasms, and the least frequent extensor spasms. Spasms are usually symmetrical, but up to 30% of cases may exhibit varying degrees of lateralisation. Unilateral brain lesions often (but not always) result in asymmetric spasms; unilateral spasms may progress to generalised spasms. Drop attacks may be the initial presentation of West syndrome of later onset. Altered or absent breathing is common during episodes. When spontaneous remissions occurs, it is typically gradual. Remission by the age of three is 50%, rising to 90% by the age of five.
Developmental The onset of epileptic spasms is often associated with developmental regression: autistic withdrawal, and loss of social smiling and of visual attention. A majority of individuals with West syndrome exhibit regression of psychomotor skills. However, developmental delay is noted in up to about two-thirds of infants with West syndrome already before the onset of spasms, whereas only about a third had exhibited normal development prior to spasm onset.
Causes Based on etiology, cases of IESS are commonly classified as either symptomatic or cryptogenic - although these terms have not been used consistently. Symptomatic cases are most often defined as those in which a clear cause can be identified, though some investigators also use the designation in cases in which there was previous clinical or imaging evidence of brain lesions and/or abnormal development was noted prior to the onset of the syndrome. Cryptogenic cases are thus contrastingly defined as those in which no specific cause can be identified, or where no such lesions or abnormalities were noted prior to syndrome onset.
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