The diagnosis, evaluation, and management of infantile spasms (IS) continue to pose significant challenges to the treating physician. Although an evidence-based practice guideline with full literature review was published in 2004, diversity in IS evaluation and treatment remains and highlights the need for further consensus to optimize outcomes in IS. For this purpose, a working group committed to the diagnosis, treatment, and establishment of a continuum of care for patients with IS and their families—the Infantile Spasms Working Group (ISWG)—was convened. The ISWG participated in a workshop for which the key objectives were to review the state of our understanding of IS, assess the scientific evidence regarding efficacy of currently available therapeutic options, and arrive at a consensus on protocols for diagnostic workup and management of IS that can serve as a guide to help specialists and general pediatricians optimally manage infants with IS. The overall goal of the workshop was to improve IS outcomes by assisting treating physicians with early recognition and diagnosis of IS, initiation of short duration therapy with a first-line treatment, timely electroencephalography (EEG) evaluation of treatment to evaluate effectiveness, and, if indicated, prompt treatment modification. Differences of opinion among ISWG members occurred in areas where data were lacking; however, this article represents a consensus of the U.S. approach to the diagnostic evaluation and treatment of IS.

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Infantile spasms: A U.S. consensus report

Few population-based studies of infantile spasms have been done, and most reports have not included comparison groups. In spite of these limitations, this review attempts to summarize what is known about the distribution, etiology, and natural history of infantile spasms in populations; discusses the limitations of current data; and includes suggestions for further population-based research. Most estimates of the incidence of infantile spasms are between 0.25 and 0.42 per 1000 live births per year. Among children less than 10 years of age, the annual prevalence of infantile spasms is 0.14 to 0.19 per 1000. The peak age at onset of spasms is 4 to 6 months, and there appears to be a slight excess of male cases. The etiology of infantile spasms is unknown for 40% to 50% of affected children. Selected syndromes (eg, Aicardi syndrome, Down syndrome, etc) and inherited disorders (eg, tuberous sclerosis) may account for as many as one third of cases. Other factors, such as intrauterine infection, "birth injury," and head trauma have not been systematically evaluated, and thus, their contribution to the etiology of infantile spasms is uncertain. Areas for future etiologic research include controlled studies of immunologic factors and in utero and postnatal infections and further exploration of the interrelationship between infantile spasms and Lennox-Gastaut syndrome.

The epidemiology and natural history of infantile spasms.

Infantile spasms is a unique disorder peculiar to infancy and early childhood. In this article, the clinical manifestations and electroencephalographic features of the disorder are described. The possible pathophysiologic mechanisms underlying infantile spasms and the relation of this disorder to other childhood encephalopathies are discussed. Finally, the treatment of patients with infantile spasms and their long-term outcome are briefly reviewed.

Infantile epileptic encephalopathy with hypsarrhythmia (Infantile spasms/West syndrome)

Infantile spasms is a severe epileptic encephalopathy of infancy. The fundamental cause is unknown, although a number of predisposing conditions are recognized. In this article, the authors critically review current knowledge concerning the pathophysiologic basis of infantile spasms and propose a new model based on developmental desynchronization. It is suggested that infantile spasms may result from a particular temporal desynchronization of two or more central nervous system developmental processes, resulting in a specific disturbance of brain function. The disturbance of function is postulated to be crucially dependent on an unbalanced maturational pattern, in which certain brain systems become dysfunctional owing to divergent developmental status. An important aspect of this model is the idea that disturbed function of a specific kind can result from multiple causative factors, and so can be associated with a variety of different anatomic and/or biochemical abnormalities. Thus, this concept is compatible with the observed diversity of pathologic findings and multiplicity of etiological associations observed in infantile spasms patients.

Pathogenesis of infantile spasms: a model based on developmental desynchronization.

To study the incidence of circulating anti-CNS antibodies in childhood neurologic diseases, a population study was undertaken. Serum samples were obtained from a total of 348 children and stored at -80 degrees C until being studied. The samples were collected when routine blood tests were being performed. In all cases informed consent was obtained. This study was approved by hospital ethics review committees. One hundred and ninety-nine of the samples were from children with no known neurologic illnesses and served as the control group. One hundred and twenty-one of the samples were from children with epilepsy and the remaining 28 from a number of different neurologic conditions. The serum samples were screened against normal, adult, autopsy-derived cerebellar and frontal cortex tissue sections and Western blots. Serum immunoreactivity was revealed using HRP-conjugated anti-human IgG. Significant findings included: (1) patients with epilepsy had an increased incidence of anti-CNS reactivity as revealed on frontal cortex immunoblots (p less than 0.05) but not on cerebellar immunoblots; (2) there was an increase in the incidence of immunoblot reactivity with age in the controls and the neurology cases; (3) there was an increased incidence of immunoblot reactivity in those cases with a presumed inflammatory central or peripheral neurologic disease; (4) in six additional cases with opsoclonus-myoclonus there was cerebellar-specific immunoreactivity with identified antigenic molecular weights of 27 and 35, and 62 kDaltons; (5) in 31 additional cases of systemic lupus erythematosus there was significant immunoblot reactivity (p less than 0.001) when compared to a subset of age-matched controls. There was no difference in immunoreactivity between males and females. There was no significant increase in immunoreactivity in those children with cognitive disturbances including developmental delay and mental retardation.

Anti-CNS antibodies in childhood neurologic diseases.

We investigated humoral and cellular immune response to brain tissues in 15 patients with West syndrome, in 9 patients with Lennox-Gastaut syndrome and in 20 healthy children. High levels of a precipitating antibody to a saline extract of brain tissue were detected in all patients; leucocyte migration inhibition test with the same antigen was found to be positive in most of them. The role of this autoimmune response in the pathogenesis of West and Lennox-Gastaut syndromes remains to the elucidated.

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M. Thereza Rezkallah-Iwasso

Papers

Demonstration of antibody and cellular immune response to brain extract in West and Lennox-Gastaut syndromes