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Infantile spasms (salaam seizures) are seizures characterized by sudden flexion of the arms, forward flexion of the trunk, extension of the legs, and hypsarrhythmia on EEG.

Infantile spasms last a few seconds and can recur many times a day. They usually manifest in children < 1 yr; peak incidence is 2 to 3 yr. Seizures may resolve spontaneously by about age 5 yr but can be replaced by other types of seizures.

Pathophysiology is unknown; however, infantile spasms may reflect abnormal interactions between the cortex and brain stem and within the hypothalamic-pituitary-adrenal axis. An immature CNS may also be a factor.

Malformations of the brain and disorders that damage the brain before a few months of age can cause infantile spasms; tuberous sclerosis is a common cause (see Neurocutaneous Syndromes: Tuberous Sclerosis). The cause may be idiopathic.

Symptoms and Signs

Spasms begin with a sudden, rapid, tonic contraction of the trunk and limbs, sometimes for several seconds. Spasms range from subtle head nodding to contraction of the whole body. They involve flexion, extension, or, more often, both (mixed). The spasms usually occur in clusters, often several dozens, in close succession; they occur typically after children wake up and occasionally during sleep.

Developmental defects (eg, in intellect) are usually present. In the first stages of the disorder, developmental regression can occur (eg, children may lose the ability to sit up or roll over).

Rate of premature death rate ranges from 5 to 31%; death often occurs before age 10 yr and is related to the etiology of the infantile spasms.

Diagnosis

• Neuroimaging
• Waking and sleep EEG
• Laboratory testing as clinically indicated

Symptoms suggest the diagnosis. Physical and neurologic examinations are done, but often no pathognomonic findings are identified except in tuberous sclerosis.

Waking and sleep EEG is done to check for specific abnormalities. Typically, the interictal pattern is hypsarrhythmic (chaotic, high-voltage polymorphic delta and theta waves with superimposed multifocal spikedischarges). Multiple variations (eg, focal or asymmetric hypsarrhythmia) are possible. The ictal pattern varies. Usually, electrical activity is markedly attenuated diffusely.

Tests to determine the cause may include

• Laboratory tests (eg, CBC with differential, plasma glucose, electrolytes, BUN, creatinine, Na, Ca, Mg, and P, liver function tests) if a metabolic disorder is suspected
• Cerebrospinal fluid analysis
• Neuroimaging (MRI)

Treatment

Infantile spasms are difficult to treat, and the optimal regimen is controversial. ACTH 20 to 60 units IM once/day may be used but has become very hard to obtain. Corticosteroids for 8 to 10 wk can also be effective. Many anticonvulsants are ineffective; valproate Some Trade Names
DEPAKENE
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is preferred, followed by clonazepam Some Trade Names
KLONOPIN
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. Nitrazepam, topiramate Some Trade Names
TOPAMAX
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, zonisamide Some Trade Names
ZONEGRAN
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, or vigabatrin may help.

A ketogenic diet may help but is difficult to maintain.

In some patients, focal cortical resection can eliminate seizures.

Last full review/revision May 2009 by Margaret C. McBride, MD

Content last modified May 2009