Acute disseminated encephalomyelitis

Abstract

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating CNS disorder with predilection to early childhood. ADEM is generally considered a monophasic disease. However, recurrent ADEM has been described and defined as multiphasic disseminated encephalomyelitis. ADEM often occurs postinfectiously, although a causal relationship has never been established. ADEM and multiple sclerosis are currently viewed as distinct entities, generally distinguishable even at disease onset. However, pathologic studies have demonstrated transitional cases of yet unclear significance. ADEM is clinically defined by acute polyfocal neurologic deficits including encephalopathy. MRI typically demonstrates reversible, ill-defined white matter lesions of the brain and often also the spinal cord, along with frequent involvement of thalami and basal ganglia. CSF analysis may reveal a mild pleocytosis and elevated protein, but is generally negative for intrathecal oligoclonal immunoglobulin G synthesis. In the absence of a specific diagnostic test, ADEM is considered a diagnosis of exclusion, and ADEM mimics, especially those requiring a different treatment approach, have to be carefully ruled out. The role of biomarkers, including autoantibodies like antimyelin oligodendrocyte glycoprotein, in the pathogenesis and diagnosis of ADEM is currently under debate. Based on the presumed autoimmune etiology of ADEM, the current treatment approach consists of early immunotherapy. Outcome of ADEM in pediatric patients is generally favorable, but cognitive deficits have been reported even in the absence of other neurologic sequelae. This review summarizes the current knowledge on epidemiology, pathology, clinical presentation, neuroimaging features, CSF findings, differential diagnosis, therapy, and outcome, with a focus on recent advances and controversies. Neurology ® 2016;87 (Suppl 2):S38-S45 GLOSSARY ADEM 5 acute disseminated encephalomyelitis; ADEM-ON 5 acute disseminated encephalomyelitis followed by optic neuritis; AHL 5 acute hemorrhagic leukoencephalopathy; IgG 5 immunoglobulin G; IPMSSG 5 International Pediatric Multiple Sclerosis Study Group; MDEM 5 multiphasic disseminated encephalomyelitis; MOG 5 myelin oligodendrocyte glycoprotein; MS 5 multiple sclerosis; NMOSD 5 neuromyelitis optica spectrum disorders; OCB 5 oligoclonal band.Acute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating CNS disorder, characterized clinically by new-onset polyfocal neurologic symptoms including encephalopathy, coupled with neuroimaging evidence of multifocal demyelination. ADEM is classically considered a monophasic illness, with highest incidence in early childhood. The first descriptions of an ADEM-like disorder with recognition of a temporal relationship to infections (especially smallpox and measles) date back to the 18th century.1 Over a century later, an association of ADEM with vaccines, notably rabies, was reported. Mortality rates were high (up to 30% for ADEM following measles infection), and neur...

Magnetic Resonance Imaging in the Acquired Demyelinating Disorders: A Pediatric Cohort Study

“…These typically affect the central and subcortical brain white matter, as well as the U-fibers, cerebellum, brainstem and spinal cord [17]. This very pattern has been observed in our patients.…”

Differential diagnosis of neuromyelitis optica spectrum disorders

“…According to the recent criteria and expert opinion for pediatric ADEM, patients with ADEM can be re-diagnosed as having either MS or NMOSD according to the number/types of relapses or test result for AQP4-Ab, respectively. 83,91 These overlaps in phenotypes should be considered especially in diagnosing pediatric ADEM patients, since a relatively higher portion (up to 9%) of pediatric NMOSD-AQP4 cases can manifest as symptoms of encephalopathy mimicking ADEM. 92 …”

Early and Long Term Outcomes of Patients with Diagnosed Acquired Demyelinating Syndromes

“…Akut dissemine ensefolamiyelit çoğunlukla monofaziktir, üç aydan uzun süre içinde yinelerse MDEM olarak tanımlanmaktadır. Tedavide üç-beş gün pulse steroid sonrasında klinik iyileşmeye rağmen, tam düzelme olmazsa idame oral steroid, hiç klinik düzelme olmazsa intravenöz immunglobulin (IVIG) ya da plazmaferez önerilmektedir (8) . Çalışmamızda, ADEM tanısı ile takipli yedi hastadan yalnızca birinde ikinci atak olması nedeni ile MDEM tanısı aldı.…”