Introduction Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease of the central nervous system (CNS). Pediatric onset multiple sclerosis (POMS) represents 10% of the cases. Our aim is to study the characteristics of a Tunisian POMS cohort. Methods Retrospective study including all children with POMS. Clinical and radiological features were analyzed. Progression Index (IP) was calculated using the Expanded Disability Status Scale (EDSS) divided by disease duration. Annualized relapse rate (ARR) defined by the number of relapses divided by disease duration was calculated. Results Fifty patients were included. At diagnosis, 48 patients had a relapsing form and 2 had a secondary progressive form. Disease modifying treatments (DMTs) were used in 40 patients. Mean ARR was 1,3 [0,2-4] before DMT and 0,64 [0-3] afterwards. ARR was correlated to the age of disease onset (p=0,011), duration between first and second attacks (p=0,013), DMT use (p<0,01) and time to DMT initiation (p=0,04). IP was 0,54 [0-2,5] before DMT and 0,43 [0-2,75] afterwards. IP was correlated to brainstem attacks (p=0,033) and contrast enhancement on cerebrospinal MRI (p= 0,035). Conclusion In this study, age of onset and duration between first and second attacks were markers of a high disease activity. Brainstem attacks and contrast enhancement were markers of a rapid progression. These markers are important to identify to adapt treatment strategies and prevent handicap accumulation.

Farah Gharsallah
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia

Hanene Benrhouma
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia

Thouraya Benyounes
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia

Zouhour Miladi
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia

Zioudi Abir
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia

Hedia Klaa
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia

Ichraf Kraoua
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia

Ilhem Benyoussef-Turki
National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia
Tunisia