The Magnetic Resonance Imaging Appearance of Monophasic Acute Disseminated Encephalomyelitis

Abstract

Acute disseminated encephalomyelitis (ADEM) is an immunologically mediated inflammatory disease of the central nervous system that typically occurs after a viral infection or recent vaccination, and is most commonly seen in the pediatric population. In 2007 the International Pediatric Multiple Sclerosis Study Group proposed a consensus definition for ADEM for application in research and clinical settings. This article gives an overview of ADEM in children, focusing on differences that have emerged since the consensus definition was established. Although the focus is on neuroimaging in these patients, a synopsis of the clinical features, immunopathogenesis, treatment, and prognosis of ADEM is provided.

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“…Possible mechanisms may include either molecular mimicry or direct inflammatory damage to myelinated neurons. 2 The prevalence of ADEM is higher in children and young adults and thought to be related to the increased frequency of viral infections and vaccination in this patient population. 6 The demonstration of multifocal hyperintensities most often affecting the subcortical white matter on fluid attenuated inversion recovery (T2/FLAIR) MRI of the brain make the identification of ADEM difficult given various other inflammatory, infectious, and rheumatologic disorders that have similar clinical and radiological presentations.…”

“…Given such ambiguity, the International Pediatric Multiple Sclerosis Study Group proposed a consensus definition for the pediatric population with the mandatory inclusion of encephalopathy in the criteria for diagnosis. 2 Despite this useful aid in identifying young patients, there still remains no clear diagnostic criterion for ADEM in adults, and therefore older individuals are more difficult to prognosticate given the paucity of reported cases and outcomes following standard ADEM therapies such as high dose corticosteroids, intravenous immunoglobulin (IVIG), and plasmapheresis (PLEX). Our patient presented with a suggestive clinical history of symptoms, physical exam and radiological signs, along with a CSF profile and histopathology suggestive of ADEM.…”

Acute disseminated encephalomyelitis: a case report of effective early immunotherapy

“…[11] encephalomyelitis characterized a monophasic disease that commonly associated with antigen challenge (febrile illness or vaccination), which is believed to function as a trigger for the inflammatory response underlying the disease. It is most seen in the pediatric population but can occur at any age.…”

Differential Diagnosis of Acute Myelopathies: An Update

“…To encompass childhood MS, the ADEM consensus criteria [24] require polysymptomatic cerebral illness including "encephalopathy". A limited or site-restricted spinal form as proposed by Scott [2] is not provided for by now, but could be the adaequate interpretation in cases, for now named "postinfectious" or "idiopathic": They share trigger (infection, vaccination) and favorable prognosis.…”