Nearly everyone with multiple sclerosis (MS) has signs of lesions in the brain, as shown by magnetic resonance imaging (MRI) scans, according to Anthony Reder, MD, a multiple sclerosis specialist and professor of neurology at the University of Chicago.
But the brain isn’t the only area where lesions can develop — MS can also attack the spinal cord. Because finding these lesions involves more elaborate imaging tests, spinal cord lesions in MS are studied less often, and many people with MS aren’t aware of the role these lesions may play in the disease process.
Researchers, too, have knowledge gaps about this feature of the disease, but one thing that seems clear is that filling these gaps may lead to a better understanding of progressive forms of multiple sclerosis.
How MS Lesions Form
Spinal cord lesions in MS “probably” form through the same mechanisms as those in the brain, says Dr. Reder.
“For some unknown reason, white blood cells escape from the bloodstream, go through the blood–brain barrier, and get into the brain tissue,” he explains. These cells cause inflammation of the brain and spinal cord — mostly in the white matter — but also the gray matter.
According to Reder, toxic chemicals produced by these cells strip the myelin insulation off the connections between nerves. The resulting lesions tend to affect multiple nerves and tend to be 1 to 2 centimeters in length or diameter.
Scientists don’t know exactly why certain people with MS have more lesions in their brain or spinal cord. What they do know, says Reder, is that spinal cord lesions “are more common in the more progressive forms of MS” than in other forms of MS. And in cases with spinal cord damage, there are sometimes actually fewer brain lesions, he adds.
How Spinal Cord Lesions Are Related to MS Symptoms
Lesions in the spinal cord often result in an increased risk of disability. A study published in the Journal of Clinical Medicine in February 2021 looked at a large group of relapsing and progressive MS patients and found that asymptomatic spinal lesions can be seen in about 15 percent of clinically stable MS patients over a median period of 14 months. According to the study authors, the presence of these lesions indicates an increased risk of future brain and spinal cord lesions that may contribute to worsening disability over time.
However, a study published in the Journal of Neuroimaging found that among several different areas of the brain and spinal cord that were imaged using MRI, only in the very top area of the spinal cord — near the second and third cervical vertebrae — was atrophy (caused by lesions) significantly associated with a greater level of self-reported disability. Even so, no specific areas of atrophy or lesions were associated with better or worse performance on a timed 25-foot walking test.
“To read this article in its entirety click this link: When MS Attacks the Spinal Cord.”