Multiple Sclerosis 101
The not-so-simple truth on this unpredictable disease
You’ve heard the term in the news, you know people who bike ride to raise funds and awareness for it, and more likely than not, you know someone affected by this disease. But what exactly is multiple sclerosis (MS)?
“It just isn’t exactly simple,” says Jerry S. Wolinsky, MD, professor of neurology at The University of Texas Health Science Center at Houston (UTHealth) Medical School. The cause of MS is not yet known, and although there are disease-modifying drugs, there is no definitive cure. Symptoms widely vary, with unpredictable episodes ranging from mild to severe. “We think that something, for reasons we don’t understand yet, has gone wrong with the immune system’s ability to differentiate between itself and something in the environment.”
In other words, our own immune defense system mistakes us for the enemy.
What we do know is that MS is a chronic and mostly progressive disease that affects the central nervous system (CNS), which comprises the brain, spinal cord and optic nerves. Scientists believe that the body’s immune system is triggered to attack the CNS specifically, which erodes and damages the myelin sheath, the insulation around the nerve fibers that protects the path a nerve signal travels. This demyelination disrupts the nerve cells that send signals to one another, which, like a bad phone connection, interrupts the flow of information within the brain and from the brain to the body.
Wolinsky, who directs the Multiple Sclerosis Research Group and Magnetic Resonance Imaging Analysis Center at UTHealth Medical School, describes MS as having “a small army of immune cells that are marching into the brain and hitting various areas in the brain, causing demyelination. These immune cells are designed to attack something they want to get rid of and, instead, are now making the mistake of getting rid of something they shouldn’t be attacking.”
These attacks can result in MS symptoms such as muscle weakness, vision problems, numbness, dizziness, poor coordination and/or an overwhelming sense of fatigue. A relapse, or episode, can occur when immune cells unpredictably activate and continue their attack. Severe scenarios include degenerating symptoms to the point of vision loss or paralysis.
As different as night and day
Not all symptoms and diagnoses are the same. In fact, it is thought that no two people have identical experiences with MS. Dissimilarities in symptoms occur when the immune cells attack different parts of the CNS. “Some symptoms are classic and easy for us to understand, but imagine what you do that doesn’t involve the central nervous system—almost nothing,” Wolinsky says. Every wire in the brain and spinal cord has insulation (myelin), so the immune system can attack any one of those—speech, vision, strength. Nothing is protected. According to the National Institute of Neurological Disorders and Stroke, classic initial symptoms include blurred or double vision, red-green color distortion or even blindness in one eye, and most patients experience muscle weakness and fatigue.
So, how is MS diagnosed? “For the most part, it’s the patient telling us there’s something wrong,” Wolinsky says. A patient may complain about progressive pain and blurred vision to their ophthalmologist, who may then determine the cause as optic neuritis, an inflammation of the optic nerve that can result in loss of vision. Although the visual disturbance might be an isolated event in the person’s lifetime, magnetic resonance imaging (MRI) showing lesions in the brain distant from the affected optic nerve can be a strong indication of MS. A closer examination of the patient’s medical history and other various tests, including evoked potentials (EP) and a spinal fluid analysis (spinal tap), can help a physician better determine the diagnosis.
Who develops MS?
Now it gets a little trickier. The risk of developing MS is higher for a population that lives farther from the equator. According to the National Multiple Sclerosis Society, researchers are looking into whether increased exposure to vitamin D from sunlight may have a protective effect on the population living near the equator. Vitamin D levels are generally quite low in people who have MS, and “it is currently, avidly believed by some that vitamin D levels are important in terms of how often people have an attack, and perhaps how severe the disease is,” Wolinsky says.
When it comes to worrying about inheriting or passing on the disease, MS is not linked to genetics as a simple one gene error. Rather, it is linked to a number of normally functioning genes that have modest to nearly imperceptible risk in isolation, but working together, clearly influence the overall risk of developing MS. “If a person in the family has MS, the risk goes up to possibly as high as 1 in 50 to 100,” Wolinsky says. The general individual has about a 1 in 1,000 chance of developing MS, depending on factors including location lived in the first 15 to 16 years of life.
MS can develop at a range of ages, with Wolinsky noting history’s youngest recorded diagnosis at 6 months old, but the disorder is most commonly diagnosed between the ages of 20 and 40 years old, and affects women more than men. “For every one male affected, three or more women are,” he says. While MS currently affects more than 400,000 people in the United States and 2.1 million in the world, the numbers of diagnoses continue to increase. “When you look at the curves of the prevalence and incidents of the disease, they have been rising since 1920 or so,” Wolinsky says. The difference in the gender ratio has also increased since the 1940s. “The factors aren’t just simple, such as we are able to diagnose it better. That accounts for a slight increase, but something else is going on,” he says.
Maintaining a quality of life
Though MS is considered chronic and incurable, the prognosis is not generally fatal. Many MS patients, with the help of medication, are able to function normally at work and home, and have a normal or near-normal life expectancy.
Certain factors are believed by some patients to be associated with how well they cope with their disease, such as high levels of stress. A trigger increasingly supported is that of smoking. People who smoke will have a more severe disease course. “It is a little less clear as to whether or not smoking is a risk factor for developing MS, but it is certainly not good once you have it,” Wolinsky says.
In the very best scenario, some patients have never had any clinical attacks associated with MS, Wolinsky says, and they “just happened, for one reason or another, to stick their head in an MRI machine” and receive an incidental diagnosis while being tested for another condition.
In the worst cases, MS can result in partial or complete paralysis. “MS is a very heterogeneous disease in terms of the way it presents itself, the way it affects people, how well people recover and don’t recover, and/or whether they have very quiet periods between attacks or the disease is rather chaotic from the beginning,” he says. While the course of MS varies from patient to patient, available medications can help control symptoms by limiting the acute inflammatory attack that goes on in the brain, with a goal of helping the patient maintain a normal quality of life.
The good news is the MS research field is evolving faster than ever. Today, there are a total of 10 U.S. Food and Drug Administration (FDA) approved medications for the treatment of MS, four of which are in the same class—interferon. In the past six months, two of the 10 FDA-approved drugs were accepted: Tecfidera™ (dimethyl fumarate), approved March 2013, and Aubagio® (teriflunomide), approved September 2012. Several more will soon be considered by the FDA. “All we had thirty years ago were steroids to give for an attack,” recalls Wolinsky. “It’s amazing. And this is a neurologic disease that is supposedly not treatable.”
Ideally, Wolinsky would like to take a patient who has a significant disability and give them a drug that would make it all go away, or have a simple vaccine. He says that this is difficult to imagine in the near term. “We know we can really change the short term—several years or more—of the course of the disease. The debate now is can we really change it over the long run?” Wolinsky says.
What we do know is that the best is yet to come when it comes to fighting MS.