Background: International studies have shown that multiple sclerosis (MS) presents before 18 years of age in 3-5% of persons with MS, labelled pediatric MS. However, smaller Danish studies have indicated that pediatric MS is underdiagnosed in Denmark. A hypothesis is that children with acute disseminated encephalomyelitis (ADEM), which includes encephalopathy, polyfocal neurological and demyelinating brain lesions, who subsequent relapse, are not classified as MS.
Methods: We undertook cohort studies using data from the Danish Multiple Sclerosis Registry and reviewed medical records of children with diagnostic codes of acquired demyelinating syndromes in the National Patient Register.
Results: The Danish incidence of pediatric MS was 0.79/100,000 (95% confidence interval: 0.71–0.88) during 1977–2015; 2% of persons with MS had onset before 18 years of age. MS was rare in children younger than 11 years of age. Among 52 children with ADEM, none progressed to MS or multiphasic ADEM during a median follow-up of 4.5 years (range=0.9–8.3 years).
Conclusion: The incidence of pediatric MS in Denmark was higher than what has been reported in most other countries; accordingly, MS is presumably not underdiagnosed in Denmark. The risk of relapse after pediatric ADEM is seemingly small.
Place of employment
Date and place of defense
10th December 2018, Panum Instutute, University of Copenhagen
Principal supervisors: Peter Vilhelm Uldall, MD, DMSC (September 1, 2015‒December 31, 2016), and Gorm Greisen, MD, DMSC (January 1, 2017‒August 31, 2018).
Principal co-supervisor: Alfred Peter Born, MD, PhD.
Co-supervisors: Morten Bjørn Blinkenberg, MD, PhD and Melinda Magyari, MD, PhD
Paper 1: Boesen MS, Magyari M, Koch-Henriksen N, Thygesen LC, Born AP, Uldall PV, Blinkenberg M. Pediatric-onset multiple sclerosis and other acquired demyelinating syndromes of the central nervous system in Denmark during 1977–2015: A nationwide population-based incidence study. Mult Scler J. 2018 Jul;24(8):1077–86.
Paper 2: Boesen MS, Magyari M, Koch-Henriksen N, Thygesen LC, Uldall PV, Blinkenberg M, Born AP. Implications of the International Paediatric Multiple Sclerosis Study Group consensus criteria for paediatric acute disseminated encephalomyelitis: a Danish nationwide population-based study. Dev Med Child Neurol. 2018 Nov 1;60(11):1123–31.