Q: My 28-year-old neighbor was just diagnosed with multiple sclerosis. Isn’t it unusual to get this disease at such a young age?
A: Multiple sclerosis (MS) is a disease of the central nervous system (CNS, made up of the brain, spinal cord and the nerves to the eyes, the optic nerves). The CNS controls many body functions by sending electrical impulses through long nerve fibers (axons), which are insulated with myelin. MS is thought to be an autoimmune disease where the body’s immune system attacks this myelin coating causing inflammation (demyelization). Think of this like the light switches in your house which send electrical signals through insulated wires to turn the lights on; if the insulation comes off the wires the signals will not be transmitted correctly and the lights will not work properly.
There are many other diseases that can affect the myelin sheath. MS is differentiated from these in that it occurs “over space and time.” This means:
- It affects at least two areas of the CNS, demonstrated by symptoms implicating at least two different areas of the CNS, an MRI (the best imaging test to diagnose MS) showing lesions in at least two separate locations or having the cerebral spinal fluid demonstrate certain antibodies.
- It does so during at least two different time periods, demonstrated by having clinical episodes separated by at least 30 days or MRI findings showing different lesions at least 30 days apart.
MS is not an inherited condition, but the predisposition to possibly get it is inherited. For example there is a 35 percent chance that someone’s identical twin will develop MS if they do. MS is virtually unheard of in some ethnic groups (such as Eskimos or Bantus), but is not uncommon in others (it is more common in Caucasians). Overall MS affects about 2 per 1,000 Americans over their lifetime.
MS is twice as common in women, and has an average age of onset of 35 (typically between 20 and 50), so your neighbor’s age at diagnosis is not unusual. MS may be “triggered” in susceptible people by something that stimulates their immune system in a particular way; for example, certain viral infections have been identified as possible triggers. It has also been noted that living in certain geographical locations is a risk factor, with the prevalence of this disease being greater the further from the equator someone lives. This may be due to environmental factors, the types of viruses (or other infections) that the patient is likely to be exposed to, or other reasons (for example it is theorized that sunlight exposure may be somewhat protective).
Any part of the CNS can be affected by MS. The specific symptoms a patient develops depends on what part of their CNS is affected. Since the CNS controls so many body functions [the sense of touch, the other senses, motor muscles (skeletal muscles that move the body as well as muscles responsible for urination, defecation, etc.), cognition, balance, etc.] there are many possible symptoms that can occur:
Page 2 of 2 - - The sense of touch is affected in 46 percent of patients, vision in 33 percent, balance in 30 percent and motor nerves (manifesting as weakness or even paralysis) in 26 percent; many people have more than one set of nerves affected, so this adds up to more than 100 percent.
- Heat sensitivity commonly occurs in MS patients.
- Some patients develop an “electric-shock” sensation brought on by certain head movements.
- Less specific symptoms such as fatigue, dizziness, changes in cognition or depression can also occur.
- Optic neuritis (inflammation of the nerve behind the eye that carries the electrical signals to the brain allowing us to see) affects almost 50 percent of people with MS, and symptoms from it (decreased visual acuity or even blindness in the affected eye or eyes) are the patient’s first MS symptoms in 1 in 200 cases.
MS is categorized into different subsets of disease. Relapsing remitting (RR) MS is the most common, accounting for 70-90 percent of cases. The course of RR MS is acute symptomatic attacks (usually lasting weeks to months and often requiring treatment) which resolve with little or no residual effects.
Many patients with RR MS go on to develop secondary progressive MS, where the symptoms do not completely resolve between attacks; the average time from the initial symptoms of RR MS to developing secondary progressive MS is 15-20 years.
About 10-20 percent of patients present with primary progressive MS, where their initial symptoms do not resolve and they eventually develop other progressive symptoms.
Systems have been developed to help quantify the severity and frequency of a patient’s symptoms. These are useful to help track the course of a patient’s disease as well as to help guide treatment.
MS is treated with medications to control the immune system to minimize inflammation (for example high dose steroid treatment). There are many disease-modulating treatments available; the specific medication that is best for an individual patient needs to be determined on a case-by-case basis.
Overall, people with MS have an almost normal life expectancy, although many do become disabled from their disease. About 90 percent of people diagnosed with MS can still walk 10 years after their diagnosis and 75 percent can still walk 15 years after diagnosis. Forty percent of MS patients have no significant disruption of their normal activities.
If you have symptoms suggestive of a MS you should seek immediate medical care. However, since MS requires the disease to be spread “over space and time,” a diagnosis of MS cannot be made from an initial episode; it is therefore important to be closely followed by a neurologist. Many treatments have been developed for MS and active research is underway looking to improve on these treatment options and hopefully to find a cure.
Jeff Hersh, PhD, MD, FAAP, FACP, FAAEP, M.D., can be reached at DrHersh@juno.com.