%0 Journal Article %T Pediatric Multiple Sclerosis: Current Concepts and Consensus Definitions %A Joaquin A. Pena %A Timothy E. Lotze %J Autoimmune Diseases %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/673947 %X Multiple sclerosis (MS), a chronic inflammatory autoimmune disease of the central nervous system (CNS) commonly diagnosed in adults, is being recognized increasingly in children. An estimated 1.7%¨C5.6% of all patients with MS have clinical symptoms before reaching the age of 18 years. In comparison with adults, the diagnosis of MS in children can be more difficult, being dismissed or misdiagnosed as other clinical disorders. Although adults and children share basic aspects of the disorder, children have distinctive clinical features, neuroimaging, laboratory, and courses of the disease. The 2010 McDonald criteria have simplified the requirements for establishing the diagnosis of MS and have been proposed to be applicable for the diagnosis of pediatric MS, mainly in children 12 years and older. This paper describes the distinctive features of common pediatric demyelinating disorders, including MS, and summarizes the most recent advances based on the available literature. 1. Introduction Multiple sclerosis (MS) is a chronic inflammatory disease of autoimmune nature, characterized by demyelination and axonal loss. MS commonly affects young adults and is considered a rare occurrence in children younger than 18 years of age. However, several studies have indicated that at least 5% of the total population with MS is composed of pediatric patients [1, 2]. Within the pediatric age group, the incidence is highest in those between 13 and 16 years of age. A small, but important, subgroup is younger than 10 years of age [3]. In 2007, an international committee proposed provisional consensus definitions that included a range of clinical and laboratory findings to facilitate unification of criteria for accurate diagnosis and to encourage and promote clinical research in pediatric demyelinating disease [4]. The original definitions have been recently reviewed and updated [5]. These unified criteria have allowed for progress to be made in the advancement of understanding the etiology, clinical manifestations, course, and neuroimaging findings of pediatric MS and other demyelinating disorders of the central nervous system (CNS). However, recognizing distinctive features of different demyelinating disorders to achieve better diagnostic certainty and optimal treatment remain challenging. 2. Demographics MS mainly affects individuals between the ages of 20 and 40 years, with a peak incidence at the age of 30 years. Population studies and case-control series show that between 1.7 and 5.6% of the MS population is younger than 18 years of age [1, 2, 6, 7] and that onset %U http://www.hindawi.com/journals/ad/2013/673947/