Multiple sclerosis (MS) is a chronic and progressive disease of the central nervous system. While the severity, symptoms, and course of the disease vary, an MS diagnosis is not the blow that it used to be. Most people with MS are diagnosed between ages 20 and 50, and the disease is significantly more prevalent in women than men. The prime cause remains a mystery, but risk factors may include ethnicity, family history, exposure to certain viruses, and low levels of vitamin D.
In MS, the immune system mistakenly attacks myelin, a fatty substance that insulates nerves and helps them communicate. Over time, this can lead to scarring (known as sclerosis or lesions) and hardening of nerve tissue in the spinal cord, brain, and eyes. These lesions can cause pain and weakness in the extremities, vision impairment, and cognitive problems, among other issues. Because the exact locations of the damage vary from person to person, so do the signs and symptoms that people experience.
4 Types of MS
Four forms of this disease have been identified: clinically isolated syndrome (CIS); relapsing-remitting MS (RRMS); primary-progressive MS (PPMS); and secondary-progressive MS (SPMS).
A person with CIS experiences a first episode of neurological symptoms lasting a minimum of 24 hours. The event is caused by either inflammation or damage to myelin in the central nervous system. Some people who experience CIS go on to develop MS of one form or another, and some don’t.
About 85 percent of people with MS are initially diagnosed with RRMS. Here are some factors that distinguish RRMS from other forms of the disease:
- People with RRMS tend to have more brain lesions, as seen on magnetic resonance imaging (MRI) scans, and these lesions contain more inflammatory cells. In contrast, people with PPMS tend to have more lesions on the spinal cord than in the brain, and fewer inflammatory cells are present.
- RRMS is generally diagnosed earlier in life than other forms of MS.
- Most people with RRMS eventually develop SPMS, a form of the illness that involves a steady and sustained worsening of symptoms over time. The transition to SPMS generally occurs after a person has had RRMS for a decade or longer.
In the early stages of this condition, people may experience blurred or double vision, muscle weakness, stiffness, spasms, tingling and numbness in the limbs, problems with coordination and balance, and fatigue. Many people with RRMS notice that certain activities or situations, such as taking a hot bath or being under a lot of stress, seem to trigger a flare-up—that is, a period of intensifying symptoms (also commonly referred to as a relapse or an exacerbation).
If damage to the central nervous system progresses in a person with RRMS, other health issues can develop. These can range from depression and various mood changes to difficulties with memory and concentration, urinary urgency and frequency (having to use the toilet very often), bowel problems such as constipation, and sexual difficulties.
The ways in which people experience RRMS vary widely. Some individuals have flare-ups, which can last anywhere from days to months before easing up, while others notice a gradual but steady increase in physical and cognitive decline over time. Still others live for years with only small reminders that they have the disease.
There’s no way to predict what course the illness will take in any given individual, but with the appropriate therapy, the majority of people with MS do not become disabled, explains Brian R. Apatoff, M.D., Ph.D., associate professor of neurology and neuroscience at Weill Cornell Medical College and director of the Multiple Sclerosis Institute in New York City. “We have some amazing therapies.”
Reasons to Be Hopeful
While there is no cure for MS, the outlook is dramatically better than it used to be for people with the disease, says Dr. Apatoff. “Research in MS is one of the most active areas in the field of neurology, with several new therapies in the pipeline,” he remarks. “MS is one of neurology’s bright and shining areas of investigation.”