What Are Multiple Sclerosis Lesions?

Multiple sclerosis lesions are scars that form in the central nervous system as a result of chronic inflammation. They are the tell-tale diagnostic sign associated with multiple sclerosis and the direct cause of the neurological symptoms associated with this disorder. Medical imaging studies such as MRIs can be used to spot lesions in a patient, and they can also be identified on biopsy or autopsy.

The term “multiple sclerosis” is a reference to the numerous scleroses, a medical term for the lesions associated with this condition, that develop in the nervous system of the patient. Also known as plaques, multiple sclerosis lesions develop as inflammation eats away at the protective myelin sheath that covers nerves. The inflammatory processes involved can be complex and are the result of autoimmune disease, where the body mistakenly identifies antigens on its own cells as evidence of foreign material in the body.

When the myelin is stripped away, it impairs nerve conduction. It is more difficult for the body to send signals through the damaged nerve and neurological symptoms like poor motor control, tremors, and slurred speech can develop. Multiple sclerosis can be a progressive disease, with the lesions growing worse over time and the symptoms also growing more severe as a result. Patients may ultimately require mobility aids and other assistive devices as their central nervous system impairments increase.

Research with the assistance of medical imaging has shown that many patients have what are known as silent lesions. These lesions do not cause clinical symptoms. The reasons some multiple sclerosis lesions cause symptoms while others do not remain mysterious, although researchers are certainly studying the issue. The central nervous system is complex, has some self-healing capabilities, and is not fully understood in its entirety, despite the amount of research that has been dedicated to understanding the brain and spinal cord.

If a doctor believes a patient is developing multiple sclerosis, medical imaging studies may be requested for diagnostic purposes. Imaging of multiple sclerosis lesions is also used as a way of monitoring the progression of the disease. Doctors will check for changes to lesions and the appearance of new lesions to learn more about how a patient's case is manifesting. Copies of old imaging studies will be kept in the patient file for future reference and patients can ask to see newer and older scans for comparison if they are interested.