Toward the definition of acute disseminated encephalitis of childhood

Acute disseminated encephalomyelitis (ADEM) is a demyelinating disorder most common in childhood and adolescence and thought to have an immune pathogenesis. Some children with ADEM develop additional temporally remote episodes of demyelination with localizations that differ from those of the initial episode and multiple sclerosis is diagnosed. Others have only a single episode. Still others have recurrent episodes in temporal proximity to or with the same localizations as the initial presentation. This review is aimed at delineating what will be required to arrive at a definition of ADEM so as to distinguish it from childhood multiple sclerosis on first presentation.

All studies to date aimed at differential characterization of ADEM and childhood multiple sclerosis have been retrospective case reviews. Each has examined a different array of historical, physical examination, laboratory, and radiologic characteristics of a differently defined patient population.

Defining ADEM and distinguishing it from multiple sclerosis early in the course of the latter disease depends critically on standardization of prospective, multicenter study design, execution, and data analysis. This has become of paramount importance, as preventive therapies have evolved for recurrent attacks of multiple sclerosis.