West Syndrome

A disorder characterized by the triad of infantile spasms, an interictal EEG pattern termed hypsarrhythmia, and mental retardation.

Generalized Flexion Epilepsy; Infantile Epileptic Encephalopathy; Infantile Myoclonic Encephalopathy; Jackknife Convulsion; Massive Myoclonia; Salaam Spasms; Infantile Spasms

Approximately 1.5-5.0 in 10,000 live births are afflicted with this disease that affects both genders equally. There is no genetic basis for the disease, although a positive family history for epilepsy is present in a minority of these patients. However, in a significant number of cases, Tuberous Sclerosis can be found and should therefore be ruled out. Basically any type of brain damage has the potential to result in infantile spasms.

Infantile spasms begin in the first year of life, most often around 4 to 7 months of age. Close neurologic examination of the child reveals abnormal mental function with cognitive deficits that are consistent with developmental delay or regression. However, there are no pathognomonic signs for West Syndrome. The symptoms are more likely a reflection of the underlying brain damage. The initial focal signs of brain injury may secondarily involve other sites of the brain resulting in the electroencephalographic picture of hypsarrhythmia. Hypsarrhythmia is characterized by abnormal, random, high voltage slow waves and spikes in cortical areas, which are variable in regard to their duration and location. The electroencephalogram has a chaotic look and is most often non-episodic. Following a spasm, fast waves and high voltage spikes may be detected. Even though the exact mechanism of action is unknown, therapy with ACTH has long been known to be one of the most effective treatment options and a wide dosage range has been used. It seems that early treatment (usually within a month after onset of infantile spams) improves the therapeutic success rate. Some neurologists combine ACTH with high doses of vitamin B6, others prefer to use nitrazepam, clonazepam, valproate, vigabatrin or lamotrigine.

Depending on their etiology, infantile spasms are usually classified as symptomatic, cryptogenic, or idiopathic. Symptomatic infantile spams are present if a factor responsible for the syndrome can be identified. Theoretically, any form of brain injury (congenital or acquired) can be associated with infantile spasms. Infantile spasms are termed cryptogenic, if no cause could be identified, although the seizures are considered to be symptomatic in origin. If psychomotor development was normal prior to the onset of the spasms, but no abnormalities can be found to explain the findings, the term idiopathic infantile spasms has been used, although for some neurologist the two terms “cryptogenic” and “idiopathic” are interchangeable. The proportions of cryptogenic and idiopathic infantile spasms therefore varies widely and with diagnostic tools becoming more and more sophisticated, their overall frequency is declining.

The treatment with ACTH may result in serious side effects including electrolyte imbalance, hypertension, left-ventricular hypertrophy, obesity, osteoporosis, opportunistic infections and behavioral problems. Preoperative work-up should therefore include a complete cell blood count (CBC) and ...

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