Many options are available to treat pain in patients with multiple sclerosis
Feb. 17, 2004
Reviewed By Brunilda Nazario, MD
When most people think of multiple sclerosis, they think of a disease that causes symptoms of weakness and motor problems -- not pain.
"About 10 or 20 years ago, there was a saying that MS causes all kinds of trouble but doesn't cause pain, which really isn't true," says Francois Bethoux, MD, director of rehabilitation services at the Mellen Center for Multiple Sclerosis Treatment and Research at The Cleveland Clinic.
"In a national survey of more than 7,000 MS patients, 70% of them had experienced some kind of pain, and at least 50% were experiencing some kind of pain at the time of the survey," Bethoux says.
The National Multiple Sclerosis Society reports that almost half of all people with MS are troubled by chronic pain.
MS pain differs from the kind of pain you might get with a headache, a joint injury, or muscle strain. "It's often more diffuse, affecting several areas of the body at a time. It often changes over time, getting worse or better for no apparent reason. It tends to fluctuate a lot," says Bethoux. "People often find it hard to describe: It's sometimes described as like a toothache, other times like a burning pain, and sometimes as a very intense sensation of pressure. It's very distressing for patients because they have a hard time explaining what their pain experience is."
So what's causing this baffling, complex, often debilitating pain? Bethoux describes it as "an illusion created by the nervous system." Normally, he explains, the nervous system sends pain signals as a warning phenomenon when something harmful happens to the body. "It's a natural defense mechanism telling us to avoid what's causing the pain," he says. "But in MS, the nerves are too active and they send pain signals with no good reason -- they're firing a pain message when they shouldn't be."
Some of the most common types of pain experienced by multiple sclerosis patients include:
Acute MS pain. These come on suddenly and may go away suddenly. They are often intense but can be brief in duration. The description of these acute pain syndromes are sometimes referred to as burning, tingling, shooting, or stabbing.
Trigeminal neuralgia or "tic doloreux." A stabbing pain in the face that can be brought on by almost any facial movement, such as chewing, yawning, sneezing, or washing your face. People with MS typically confuse it with dental pain. Most people can get sudden attacks of pain that can be triggered by touch, chewing, or even brushing the teeth.
Lhermitte's sign. A brief, stabbing, electric-shock-like sensation that runs from the back of the head down the spine, brought on by bending the neck forward.
Burning, aching, or "girdling" around the body. This is called dysesthesia by physicians.
There are also some types of pain related to MS that are described as being chronic in nature -- lasting for more than a month -- including pain from spasticity that can lead to muscle cramps, tight and aching joints, and back or musculoskeletal pain. These chronic pain syndromes can often be relieved by anti-inflammatory drugs, massage, and physical therapy.
Anticonvulsant Drugs Offer Relief
For the most part, however, acute MS pain can't be effectively treated with aspirin, ibuprofen, or other common OTC pain reliever medications or treatments. "Since most MS pain originates in the central nervous system, it makes it a lot more difficult to control than joint or muscle pain," says Kathleen Hawker, MD, an assistant professor of neurology in the multiple sclerosis program at the University of Texas Southwestern Medical Center in Dallas (UTSW).
So what's the alternative? In many cases, the treatment of choice is one of a range of anticonvulsant medications, such as Neurontin and Tegretol. "The main thing that links them all up is that we're not quite sure how they work -- either for seizures or for pain," says Hawker. Since the FDA hasn't officially approved these anticonvulsants for the treatment of pain, they're all being used "off-label," but Neurontin, for example, is prescribed five times more often for pain than for seizures, says Hawker.
"In the vast majority of patients, these medications do work," says George Kraft, who directs the Multiple Sclerosis Rehabilitation, Research, and Training Center and the Western Multiple Sclerosis Center at the University of Washington in Seattle. "There's a problem, though, in that most of them can make people sleepy, groggy, or fatigued, and MS patients have a lot of fatigue anyway."
The good news: Most pain in MS can be treated. There are more than half a dozen of these anticonvulsants, and they all have a slightly different mechanism of action and different side effects. The side effects of these drugs can also include low blood pressure, possible seizures, and dry mouth. They can also cause some weight gain.
"Some drugs are so similar to each other that if one drug in the class fails, another is unlikely to work," says Hawker. "That's not the case with these. Which one you use for which patient depends on the side effect profile."
Finding the right anticonvulsant is all about trial and error, says Bethoux. "We'll start them at the lowest possible dose of one medication and increase it until the person feels comfortable or until side effects aren't tolerable. If one medication doesn't work, we'll try another," he says. "It's a process that can take a long time, but it's the only way we have to do this."
New Frontiers in Treatment
Some patients, however, still haven't found the right drug and the right dosage to control their pain. "About 1% to 2% of patients have extremely refractory pain that's very hard to manage," says Kraft. So MS experts are still looking for options to add to their treatment arsenal.
One intriguing possibility: Botox. The anti-wrinkle injections popular with Park Avenue socialites have shown promise in helping to control some types of MS pain. Botox, which acts locally to temporarily paralyze a nerve or muscle, has been used for years at some multiple sclerosis clinics, including Hawker's, to manage spasticity and bladder problems. "Serendipitously, we found that it also seemed to have an effect on pain," she says. "It's far from being a known treatment for pain in MS at this point, but it's an exciting possibility."
UTSW, along with two other centers, will soon be launching a small study involving about 40 patients with MS to assess whether Botox can indeed relieve the stabbing pain of trigeminal neuralgia. "There are no systemic side effects, only mild local facial weakness. The biggest drawback is that you can only inject it in a limited area, so even if we do find that it's effective against MS pain, Botox will certainly not replace any of the medications we currently have. But it may be used in very specific conditions like trigeminal neuralgia," Hawker says.
Kraft, meanwhile, has recently begun a study looking at a very different
approach to MS pain: hypnosis. "It's well known that there is a 'gating'
mechanism in the higher cognitive parts of the brain to let signals come
through to the consciousness. There can be all kinds of mischief in the
pain fibers in the spinal cord, but it has to get through to the cortex
before it's painful," he says. "With hypnosis, we hope to block or at least
reduce the interpretation of that stimulus as a painful stimulus. It looks
promising so far, and obviously it doesn't have the problem of medication
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