West Syndrome: A Review and Guide for Paediatricians

The International League Against Epilepsy (ILAE) Commission on Classification and Terminology has revised concepts, terminology, and approaches for classifying seizures and forms of epilepsy. Generalized and focal are redefined for seizures as occurring in and rapidly engaging bilaterally distributed networks (generalized) and within networks limited to one hemisphere and either discretely localized or more widely distributed (focal). Classification of generalized seizures is simplified. No natural classification for focal seizures exists; focal seizures should be described according to their manifestations (e.g., dyscognitive, focal motor). The concepts of generalized and focal do not apply to electroclinical syndromes. Genetic, structural-metabolic, and unknown represent modified concepts to replace idiopathic, symptomatic, and cryptogenic. Not all epilepsies are recognized as electroclinical syndromes. Organization of forms of epilepsy is first by specificity: electroclinical syndromes, nonsyndromic epilepsies with structural-metabolic causes, and epilepsies of unknown cause. Further organization within these divisions can be accomplished in a flexible manner depending on purpose. Natural classes (e.g., specific underlying cause, age at onset, associated seizure type), or pragmatic groupings (e.g., epileptic encephalopathies, self-limited electroclinical syndromes) may serve as the basis for organizing knowledge about recognized forms of epilepsy and facilitate identification of new forms.

To reach a broad consensus on case definitions, outcomes, and outcome measures that will ease future study design and facilitate comparison of data from different studies of infantile spasms and West syndrome. Persons who had recently presented or published first-author original research in this field were invited to participate in an e-mail Delphi process and to invite other investigators or clinicians who they thought might participate. The process consisted of six rounds, anonymous except to the facilitator. In total, responses were received from 46 participants. The final statement was approved by 31 participants from 15 countries. It concluded that the primary clinical outcome, cessation of spasms, should denote absence of witnessed spasms from within 14 days of commencement of treatment, and for > or =28 consecutive days from the last witnessed spasm. Primary electroclinical outcome denotes cessation of spasms with resolution of hypsarrhythmia. West syndrome should be a defined subset of the syndrome of infantile spasms. An infantile spasms single-spasm variant should be recognized. Ways are suggested of handling subtle spasms in the context of clinical studies. It proposes a standard for reporting modifying and atypical features of hypsarrhythmia, a minimal set of baseline characteristics and outcomes that should be reported in trials of infantile spasms, and suggests a standard definition of relapse. Consensus was not reached on a definition of hypsarrhythmia. We reached a clear consensus on many aspects of study design for the investigation of infantile spasms, although incomplete consensus was found on how to define EEG criteria.

To update the 2004 American Academy of Neurology/Child Neurology Society practice parameter on treatment of infantile spasms in children. MEDLINE and EMBASE were searched from 2002 to 2011 and searches of reference lists of retrieved articles were performed. Sixty-eight articles were selected for detailed review; 26 were included in the analysis. RECOMMENDATIONS were based on a 4-tiered classification scheme combining pre-2002 evidence and more recent evidence. There is insufficient evidence to determine whether other forms of corticosteroids are as effective as adrenocorticotropic hormone (ACTH) for short-term treatment of infantile spasms. However, low-dose ACTH is probably as effective as high-dose ACTH. ACTH is more effective than vigabatrin (VGB) for short-term treatment of children with infantile spasms (excluding those with tuberous sclerosis complex). There is insufficient evidence to show that other agents and combination therapy are effective for short-term treatment of infantile spasms. Short lag time to treatment leads to better long-term developmental outcome. Successful short-term treatment of cryptogenic infantile spasms with ACTH or prednisolone leads to better long-term developmental outcome than treatment with VGB. Low-dose ACTH should be considered for treatment of infantile spasms. ACTH or VGB may be useful for short-term treatment of infantile spasms, with ACTH considered preferentially over VGB. Hormonal therapy (ACTH or prednisolone) may be considered for use in preference to VGB in infants with cryptogenic infantile spasms, to possibly improve developmental outcome. A shorter lag time to treatment of infantile spasms with either hormonal therapy or VGB possibly improves long-term developmental outcomes.