Epidemiological and clinical characteristics of multiple sclerosis in paediatric population in Slovenia: A descriptive nation-wide study

Background: Although multiple sclerosis usually affects young adults, paediatric-onset multiple sclerosis (pMS) is increasingly recognized in the past ten years. The aim of the present study was to evaluate the incidence of pMS in Slovenia and to characterize the clinical, laboratory and neuroradiological characteristics of pMS at the disease onset. Methods: We performed a national retrospective descriptive study including all patients diagnosed with pMS between January 1992 and June 2017. We reviewed data of all patients younger than 18 years at the first demyelinating event. Results: The estimated incidence of pMS was 0.66/100,000 children per year. We included 61 patients (77% were female) with a median age at diagnosis of 16.3 years. In 4 patients, onset of pMS was before the age of 12 years old (childhood-onset pMS). Relapsing-remitting multiple sclerosis was most prevalent, with only 2 patients presenting a primary progressive pMS. Polysymptomatic pMS was found at onset in 59% of patients and monosymptomatic in 41%. In the cerebrospinal fluid study, 88% of patients had positive oligoclonal bands. Brain magnetic resonance imaging studies showed a predominant supratentorial involvement (100% of patients). Conclusion: The clinical pattern of pMS in our cohort of patients was characterized by polysymptomatic presentation and predominantly sensory symptoms at onset, developing a relapsing-remitting pMS pattern. It is important to gather more information about the incidence of pMS and its initial presentation and clinical course to improve early recognition and appropriate initiation of immunomodulatory treatment.