Elif Bulut

Brain lesions are frequent in pediatric-onset neuromyelitis optica spectrum disorder (NMOSD) and distinguishing the clinical picture from other acquired demyelinating syndromes, such as acute disseminated encephalomyelitis (ADEM), could be very challenging, especially in patients presenting with brain manifestations without optic neuritis or myelitis.¹ NMOSD has a very different treatment approach compared with ADEM and other demyelinating diseases, which makes the task of discriminating these disease entities even more important.^2,3 Therefore in the current study, we aimed to provide a detailed characterization of brain MRI abnormalities in pediatric-onset NMOSD and to identify MRI findings that could help differentiate it from ADEM.

The involvement of the thalamus and the posterior limb of the internal capsule was significantly higher in patients with ADEM in our study and could favor the diagnosis of ADEM over NMOSD. On the other hand, no other MRI findings, including lesion expansion, T1 hypointensity, contrast enhancement/pattern, and diffusion characteristics, were found to be significantly different between these disease entities. In this regard, we want to emphasize that a child with NMOSD might present with similar clinical and MRI findings of ADEM and neuroradiologists should be aware of this fact in establishing their differential diagnosis. It is very important to suggest the possibility of NMOSD in the radiology reports so that the neurologists or pediatricians consider antibody testing if they have not already done so. NMOSD is a relapsing autoimmune demyelinating disease and the morbidity is high after every attack; therefore, antibody testing at the initial episode is tremendously important for timely diagnosis and treatment to avoid clinical sequelae like vision loss and paraplegia.

In the same context, we also want to draw attention to myelin oligodendrocyte glycoprotein (MOG) antibody–associated disease, which has emerged as a distinct entity in recent studies.^4,5 Encephalomyelitis in MOG antibody–associated disease is more likely to be associated with younger age at onset and has overlapping clinical and MRI findings with ADEM.^6,7 One of our limitations in the study is the fact that not all patients were tested for anti-MOG antibody, because testing for this antibody was not widely available at the time of the study design. Therefore, future studies with larger cohorts in which MOG antibody and anti-aquaporin-4 antibody statuses are specified are needed to validate and extend our findings.

References

1. Wingerchuk DM, Banwell B, Bennett JL, et al. International consensus diagnostic criteria for neuromyelitis optica spectrum disorders. Neurology 2015;85:177–89, 10.1212/WNL.0000000000001729
2. Wingerchuk DM, Weinshenker BG. Neuromyelitis optica. Curr Treat Options Neurol 2008;10:55–66, 10.1007/s11940-008-0007-z
3. Lotze TE, Northrop JL, Hutton GJ, et al. Spectrum of pediatric neuromyelitis optica. Pediatrics 2008;122:e1039–47, 10.1542/peds.2007-2758
4. Duignan S, Wright S, Rossor T, et al. Myelin oligodendrocyte glycoprotein and aquaporin-4 antibodies are highly specific in children with acquired demyelinating syndromes. Dev Med Child Neurol 2018;60:958–62, 10.1111/dmcn.13703
5. Hennes EM, Baumann M, Lechner C, et al. MOG spectrum disorders and role of MOG-antibodies in clinical practice. Neuropediatrics 2018;49:3–11, 10.1055/s-0037-1604404
6. Salama S, Khan M, Pardo S, et al. MOG antibody-associated encephalomyelitis/encephalitis. Mult Scler 2019;25:1427–33, 10.1177/1352458519837705
7. Salama S, Khan M, Levy M, et al. Radiological characteristics of myelin oligodendrocyte glycoprotein antibody disease. Mult Scler Relat Disord 2019;29:15–22, 10.1016/j.msard.2019.01.021

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