The Syndrome That Could Be A Precursor To Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease where the immune system mistakenly attacks the protective sheaths around the nerve fibers (via Mayo Clinic). This damages the nerve fibers, which disrupts the communication of signals between the brain and the rest of the body. Although each person with MS can experience different symptoms that can come and go, many people with MS experience muscle weakness, difficulty with coordination, and cognitive issues.

Although the cause of MS isn't known, researchers are looking into how the disease progresses in the body. A possible precursor to MS is called radiologically isolated syndrome (RIS). People with RIS don't have symptoms of MS, but show similar lesions on the brain or spinal cord, according to a 2020 article in the American Journal of Neuroradiology. Typically, these lesions are found during an MRI scan when someone has experienced headache, head trauma, or dizziness. It's unknown how many people might have RIS, since it's only found during an MRI. RIS is more likely in healthy relatives of people with MS.

According to My MS Team, some researchers believe RIS reflects the same condition as MS, and that RIS is a precursor to the MS. However, not all people with RIS develop MS.

Researchers are also looking into why some people with RIS develop MS and some don't. According to a 2020 study in the Annals of Neurology, being male, younger, and having lesions on the spinal cord poses an increased risk of developing MS in five years. About half of the people with RIS could experience a clinical event. This clinical event is an episode of symptoms due to inflammation and deterioration of the casing around nerve cells (called demyelination), according to the National Multiple Sclerosis Society. These symptoms can include loss of vision, numbness, dizziness, or problems walking. In order to be classified as a clinical event, these symptoms must last for 24 hours. This first event is called clinically isolated syndrome (CIS), which is considered to be the first course of MS.

There is a possibility that the location of the lesions might predict MS. A 2011 study in Neurology found that 84% of RIS patients who had lesions on the cervical spine developed clinically isolated syndrome (CIS) or MS in less than two years.

Many times, RIS remains silent because the lesions might be in less critical areas, according to a 2022 review in Frontiers in Neurology. There also could be a low level of inflammation that might not cause symptoms, or the brain is trying to repair itself. Yet once an episode occurs, people might recognize previous symptoms in hindsight. The likelihood of this silent demyelination is usually higher in people who have family members with MS.

Because people with RIS don't experience any symptoms, a RIS diagnosis is difficult. If brain or spinal cord lesions are found in an MRI, then a doctor will look at your medical history and do a neurological examination (via Cedars Sinai). A spinal tap, spinal fluid analysis, and a test of your nerve function could also help diagnose or rule out RIS. Because there is no cure for RIS, your medical provider will continually observe you to see if there is any progression of the condition.

Because vitamin D supplements, preventing metabolic disorders, and quitting smoking have been linked to a reduced risk of MS, it's possible that these measures might also prevent RIS from progressing to MS, according to the 2022 review in Frontiers in Neurology. Clinical trials are underway looking for ways to treat the progression of RIS using medications such as teriflunomide, dimethyl fumarate, and ocrelizumab. A 2023 study presented at the American Academy of Neurology's annual meeting found that people with RIS who took teriflunomide reduced their risk of a clinical event by 63% compared to those given a placebo.