Results of the ESPED Study “Neuromyelitis Optica Spectrum Disorders in Children and Adolescents

Background: Neuromyelitis optica spectrum disorders (NMOSD) are severe autoimmune disorders of the central nervous system characterized by recurrent episodes of uni- or bilateral optic neuritis (ON), transverse myelitis (TM) and brain stem syndromes (BS). The majority of adult patients have serum antibodies against aquaporin-4 (AQP4-ab). In pediatric patients, AQP4-ab are less frequently detectable than antibodies against myelin oligodendrocyte glycoprotein (MOG-ab). Until recently, patients with MOG-ab were thought to have a better prognosis and a milder disease course than patients with AQP4-ab. However, recent studies could show that pediatric and adult NMOSD patients with MOG-ab may also have recurrent disease courses.

Objectives: Evaluation of epidemiological data regarding incidence of pediatric NMOSD in Germany. Furthermore, differences between the three above mentioned groups in terms of radiological characteristics, cerebrospinal fluid (CSF) profile, therapy response and long-term outcome need to be assessed. Therefore, studies with adequate patient numbers are needed to evaluate the epidemiology, long-term outcome and prognosis of pediatric patients with NMOSD, either with AQP4-, MOG- or without antibodies.

Methods: For this investigation we only included patients who were referred to us between 01.03.2017 and 28.02.2019 via our ESPED study. We received data regarding clinical symptoms, therapy regimen and therapy response via a standardized questionnaire. These clinical data were evaluated together with the CSF and antibody status as well as the cerebral and spinal imaging methods.

Results: Overall 39 patients were referred. For 3 patients the completed questionnaires are missing. 14 of these 36 children and adolescents did not fulfill the inclusion criteria and were excluded. Among the remaining 22 patients, 7 were diagnosed with NMOSD (4 females, 3 males; median age 11 years). 15 patients did not fulfill the criteria completely. The reason to follow these patients (4/15 MOG-ab pos) nevertheless is their risk of experiencing another episode and thus fulfilling diagnostic criteria for NMOSD. Of the 7 definite NMOSD patients 3 showed AQP4-ab, 3 MOG-ab and 1 neither of these antibodies. Both patients with MOG-ab presented with simultaneous ON and LETM. All patients received an intravenous methylprednisolone pulse therapy at presentation, only one patient (AQP4-ab pos) subsequently obtained long-term therapy with rituximab.

Conclusion: Considering 11 million children under 14 years of life in Germany, the incidence for NMOSD is approximately 0,03 per 100.000 children. This would be clearly below already published data for adult patients. However, it is unlikely that all newly diagnosed children were referred to our study, thus, the true incidence is indeed higher.

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