米any options are available to treatpainin patients withmultiple sclerosis.
By Gina Shaw
WebMD Feature
Reviewed By Brunilda Nazario
When most people think ofmultiple sclerosis, they think of a disease that causes symptoms ofweaknessand motor problems -- notpain.
"About 10 or 20 years ago, there was a saying that米Scauses 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米ultiple Sclerosis Treatment并在克利夫兰诊所的研究。
"In a national survey of more than 7,000米Spatients, 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米ultiple SclerosisSociety reports that almost half of all people with米Sare troubled bychronic pain.
米S pain differs from the kind of pain you might get with aheadache, 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 atoothache, 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 neuralgiaor "tic doloureux." 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 theteeth.
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 fromspasticitythat can lead tomuscle cramps, tight and aching joints, and back ormusculoskeletal pain. Thesechronic painsyndromes can often be relieved by anti-inflammatorydrugs,massage, and physical therapy.
Anticonvulsant Drugs Offer Relief
For the most part, however, acute MS pain can't be effectively treated withaspirin,ibuprofen, or other common OTCpain relievermedications or treatments. "Since most MS pain originates in the central nervous system, it makes it a lot more difficult to control than joint ormuscle 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 asNeurontinandTegretol. "The main thing that links them all up is that we're not quite sure how they work -- either forseizuresor 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 forseizures, 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 offatigueanyway."
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 includelow blood pressure, possible seizures, anddry mouth. They can also cause someweight 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.
同时,卡夫looki最近开始研究ng 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 side effects."
Published Feb. 17, 2004.
SOURCES: Francois Bethoux, MD, director of rehabilitation services, the Mellen Center for Multiple Sclerosis Treatment and Research, The Cleveland Clinic. Kathleen Hawker, MD, assistant professor of neurology, University of Texas Southwestern Medical Center, Dallas. George Kraft, director, Multiple Sclerosis Rehabilitation, Research, and Training Center and director, Western Multiple Sclerosis Center, University of Washington, Seattle. National Multiple Sclerosis Society.
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