Multiple sclerosis is a chronic disease in which the immune system attacks myelin, the fatty substance that insulates nerve cells.

Like the jacket on an electrical wire, myelin ensures that the electrical signals traveling along our nerves do so effectively. As the myelin breaks down, a process known as demyelination, those signals get weaker and the messages they transmit break down.

The result of demyelination is a variety of conditions and disruptions in body processes, from vision problems to tingling in the hands and feet.

“It’s really highly variable,” says Tidelands Health neurologist Dr. Mac DeHart-McCoyle, who sees patients at Tidelands Health Neurosciences. “It just depends on where the plaque would be in the brain.”

Multiple sclerosis, or MS, comes in three degrees:

Relapsing-remitting: The most common type of MS comes and goes with symptoms developing over days or weeks and then abating partially or entirely for months or even years.

Secondary-progressive: Relapsing-remitting MS evolves into this type of MS in about 50 percent of cases as the symptoms become progressively worse with or without remission. It can take a decade or more to develop and results in a variety of physical disabilities, including trouble walking.

Primary-progressive: Some people experiencing MS develop this form, which features a gradual onset and steady progress in symptoms without any relapse or remission.

Sometimes, people show early signs that might point to MS before a diagnosis. These signs fall into two categories:

Clinically-Isolated Syndrome

This is when someone has a single episode of symptoms, like blurry vision, numbness or trouble with balance, that are caused by inflammation in the nervous system. It’s called “isolated” because it happens once, and doctors aren’t yet sure if it will develop into MS. Follow-up tests and monitoring help determine what comes next.

Radiologically-Isolated Syndrome

In this case, the person doesn’t have any symptoms, but during an MRI scan, doctors spot changes in the brain or spinal cord that look like MS. These changes suggest the person might be at risk for developing MS later, even though they haven’t felt anything unusual yet.

For people developing MS, the eyes are often the first organs to feel the effects. As the disease attacks the optic nerve, patients can experience blurred vision for several days or even sudden blindness that improves over a day or two. They can also experience sharp pain when they move their eyes.

“Typically, when you get a bout of optic neuritis, it’s in one eye and it comes on quickly. It can be confused with a stroke,” Dr. DeHart-McCoyle says. “It’s really important that patients let us know if they have a loss of vision.”

MS patients have a wide range of treatment options, from steroids to infusions, to help manage their symptoms and reduce the impact of the condition in part by calming the immune system. Because no two cases of MS are the same, each treatment is tailored to the individual patient.

The exact cause of MS remains a mystery. It may have a genetic component. It may have an environmental component. It may develop from the interaction of genetics and the environment.

“It’s still not completely understood why some people develop it,” Dr. DeHart-McCoyle says.

Ultimately, diagnosing MS is about eliminating other possible sources of the symptoms, such as:

• Neuromyelitis optica
• Myelin oligodendrocyte glycoprotein antibody disease
• Diabetes
• Other autoimmune conditions
• Neoplasms
• Infections

“A lot of neurological diseases are not going to be solved in a 30-minute visit,” he adds. “Neurology is a very objective specialty, and data, along with localization, is key to a sound diagnosis.”