Expert Interview

Radiologically Isolated Syndrome: A condition that often precedes an MS diagnosis in children

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Naila Makhani, MD completed medical school training at the University of British Columbia (Vancouver, Canada). This was followed by a residency in child neurology and fellowship in MS and other demyelinating diseases at the University of Toronto and The Hospital for Sick Children (Toronto, Canada). Concurrent with fellowship training, Dr. Makhani obtained a Masters’ degree in public health from Harvard University. Dr. Makhani is the Director of the Pediatric MS Program at Yale and the lead investigator of a multi-center international study examining outcomes following the radiologically isolated syndrome in children.

Q1. Could you please provide an overview of Radiologically Isolated Syndrome ?

A1. Radiologically Isolated Syndrome (RIS) was first described in adults in 2009. Since then it has also been increasingly recognized and diagnosed in children. RIS is diagnosed after an MRI of the brain that the patient has sought for reasons other than suspected multiple sclerosis-- for instance, for evaluation of head trauma or headache. However, unexpectedly or incidentally, the patient’s MRI shows the typical findings that we see in multiple sclerosis, even in the absence of any typical clinical symptoms. RIS is generally considered a rare syndrome.

Q2. You created Yale Medicine’s Pediatric Multiple Sclerosis program which advocates for the eradication of MS. What criteria defines a rare disease? Does RIS meet these criteria? And if so, how?

A2. The criteria for a rare disease vary, depending on the reference. In the US, a rare disease is defined as a condition that affects fewer than 200,000 people, in total, across the country. By contrast, in Europe, a disease is considered rare if it affects fewer than one in every 2,000 people within the country’s population.

In the case of RIS, especially in children, we suspect that this is a rare condition, but we don't know for sure, as there have been very few population-based studies. There is one large study that was conducted in Europe that found one case of RIS among approximately 5,000 otherwise healthy children, who were between 7 and 14 years of age. I think that's our best estimate of the overall prevalence of RIS in children. Using that finding, it likely would qualify as a rare condition, although, as I said, we really don't know for sure, as the prevalence may vary among different populations or age groups.

Q3. How do you investigate and manage RIS in children? What are some of the challenges?

A3. For children with radiologically isolated syndrome, we usually undertake a comprehensive workup. This includes a detailed clinical neurological exam to ensure that there are no abnormalities that would, for instance, suggest a misdiagnosis of multiple sclerosis or an alternative diagnosis. In addition to the brain MRI, we usually obtain an MRI of the spinal cord to determine whether there is any spinal cord involvement. We also obtain blood tests. We often analyze spinal fluid as well, primarily to exclude other alternative processes that may explain the MRI findings. A key challenge in this field is that there are currently no formal guidelines for the investigation and management of children with RIS. Collaborations within the pediatric MS community are needed to develop such consensus approaches to standardize care.

Q4. What are the most significant risk factors that indicate children with RIS could one day develop multiple sclerosis?

A4.This is an area of active research within our group. So far, we've found that approximately 42% of children with RIS develop multiple sclerosis in the future; on average, two years following their first abnormal MRI. Therefore, this is a high-risk group for developing multiple sclerosis in the future. Thus far, we've determined that in children with RIS, it is the presence of abnormal spinal cord imaging and an abnormality in spinal fluid – namely, the presence of oligoclonal bands – that are likely the predictors of whether these children could develop MS in the future. a child’s possible development

Q5. Based on your recent studies, are there data in children highlighting the potential for higher prevalence in one population over another?

A5. Thus far, population-based studies assessing RIS, especially in children, have been rare and thus far have not identified particular subgroups with increased prevalence. We do know that the prevalence of multiple sclerosis varies across different age groups and across gender. Whether such associations are also present for RIS is an area of active research.

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