The natural course of clinically isolated syndrome in pediatric patients

Background: The first episode of central nervous system (CNS) symptoms with a presumed inflammatory demyelinating cause is defined as clinically isolated syndrome (CIS) according to the 2007 consensus of the International Pediatric Multiple Sclerosis Study Group, which developed diagnostic criteria for CNS demyelination disease in children. Using this definition of CIS, we attempted to identify the natural course of pediatric patients with CIS in a single Korean institution and to determine the factors affecting their prognosis. Methods: We retrospectively reviewed the medical records of all pediatric patients (age <18 years old) who presented with clinical symptoms of CNS events between 1997 and 2008. Results: We identified 32 patients with CIS. Their mean age with standard deviation was 10.0 ± 4.1 years. The most common type of presentation of CIS was optic neuritis (ON). Sixteen (16/32, 50%) patients experienced a second demyelinating event. The mean interval between the first event and the recurrent episode was 21 ± 20 months. The mean follow-up was 6.1 ± 1.6 years. Eleven (34%) patients developed childhood onset multiple sclerosis (MS). In contrast to previous studies, asymptomatic brain lesions on magnetic resonance imaging (MRI) and the presence of cerebrospinal fluid (CSF) oligoclonal bands (OCBs) were not predictors of conversion to MS. Conclusion: In our study, a second relapse and initial presentation with brain stem, cerebellar, cerebral dysfunction, or multifocal CIS were strongly associated with the development of MS (p = 0.002). Despite clinical definitions and increased understanding of CIS in children, challenges remain in predicting its progression to a chronic demyelinating disease.