Pediatric Acquired Demyelinating Disorders

Multiple Sclerosis and Other Acquired Demyelinating Diseases of the Central Nervous System

Acquired demyelinating diseases of the central nervous system (CNS) comprise inflammatory conditions, including multiple sclerosis (MS) and related diseases, as well as noninflammatory conditions caused by toxic, metabolic, infectious, traumatic, and neurodegenerative insults. Here, we review the spectrum of diseases producing acquired CNS demyelination before focusing on the prototypical example of MS, exploring the pathologic mechanisms leading to myelin injury in relapsing and progressive MS and summarizing the mechanisms and modulators of remyelination. We highlight the complex interplay between the immune system, oligodendrocytes and oligodendrocyte progenitor cells (OPCs), and other CNS glia cells such as microglia and astrocytes in the pathogenesis and clinical course of MS. Finally, we review emerging therapeutic strategies that exploit our growing understanding of disease mechanisms to limit progression and promote remyelination.

Multiple sclerosis under the age of ten: the challenge of a rare diagnosis in a special population - a case series

Introduction

Multiple sclerosis (MS) is a chronic inflammatory demyelinating and degenerative disease of the central nervous system which, when it begins before the age of 18, is defined as paediatric MS. Most common clinical presentations include long tract involvement, brainstem/cerebellum syndromes, optic neuritis and acute disseminated encephalomyelitis. Paediatric-onset MS typically has a more inflammatory-active course and a higher lesion burden in imaging studies, but an extensive post-relapse recovery, with a slower long-term disability progression. The first demyelinating clinical attack occurs before 10 years old in less than 1% of patients, and, in this special population, the condition has particularities in clinical presentation, differential diagnosis, diagnostic assessment, current treatment options and outcome.

Clinical cases

We present the cases of four Caucasian children (2 girls) diagnosed with relapsing-remitting MS before the age of ten, with a mean age at the time of the first relapse of 7.4 ± 2.4 years. Clinical presentation included optic neuritis, myelitis, brainstem syndrome, and acute disseminated encephalomyelitis. Baseline MRI identified several lesions, frequently large and ill-defined. Two patients were included in clinical trials and two patients remain in clinical and imaging surveillance.

Conclusion

Diagnosis of MS before the age of 10 years is rare, but it has significant long-term physical and cognitive consequences, as well as a substantial impact on the current and future quality of life of the child and family. Early and correct diagnosis is essential. Prospective, randomized, large cohort studies are needed to assess the efficacy and safety of disease-modifying treatments in children under the age of ten.

Monophasic Acquired Demyelinating Syndromes of the Central Nervous System in Children

Acquired demyelinating syndromes of the central nervous system are immune-mediated demyelinating disorders that can affect the brain, optic nerves, and spinal cord. These disorders have become increasingly recognized in children due to advances in imaging techniques, improvements in diagnostic testing, extensive research into understanding the pathophysiology underlying these disorders, and collaborative multi-institutional efforts to raise awareness of these disorders in children. Moreover, developments in the field of neuroimmunology have allowed us to identify autoantibodies that have presumed causal roles in acquired demyelinating syndromes. Identification of these autoantibodies helps determine clinical course (ie, monophasic vs relapsing course), prognosis, and treatment approach. Acquired demyelinating disorders can affect both children and adults. However, the clinical features, disease course, and treatments are often unique in the pediatric population. Thus, it is important to understand the spectrum of these disorders in children to help provide a timely diagnosis and prompt treatment to achieve optimal outcomes. In this article, the epidemiology, clinical features, diagnosis, treatment, and outcomes of the most common monophasic acquired demyelinating syndromes in children will be reviewed.