Pain and MS: Neuropathic Pain
There is pain in MS. It can be acute or chronic, generally categorized as neuropathic, musculoskeletal, or tertiary. Let's begin looking at details.
Sometimes the nervous system does not function properly, and it actually becomes the cause of pain. Neuropathic (nervous disease) pain is the most common kind in MS. That makes sense because MS is a central nervous system disease. Today I am going to talk about details and specific neuropathic pain.
Francois Bethoux, MD, director of rehabilitation services at the Mellen Center for Multiple Sclerosis Treatment and Research at The Cleveland Clinic talks about how MS pain differs from everyday headaches or muscle strains. "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."
This type of pain is not caused by an injury; rather, when nerves are damaged they become hypersensitive, and the nerves themselves generate the pain. A second cause of neuropathic pain is damaged myelin that allows pain signals to be mistakenly communicated.
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. "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."
So there are times when we feel intense pain for no reason other than a malfunctioning nervous system. It sounds suspiciously like the pain is all in our heads. However, this is not imagined pain, the pain is real and sometimes quite intense and debilitating. What kind of pain is this?
Neuropathic pain can be either acute or chronic, and it presents itself in many different specific ways. Warning: Many of these pains are identified by medical terms that sound technical and are awkward to pronounce, but their descriptions are plain English and easy to the to understand. Here are some common neuropathic pains experienced by MSers --
Allodynia is a particularly painful sensation as a response to a normally innocuous stimulus such as a light touch, bed sheets, or clothes. It is usually short-lived, and last only as long as the stimulus remains.
Dysesthesias is a burning, aching, itching, or girdling around the body. It has also been described as feeling as if there is acid under the skin. It may be triggered by a light touch or by nothing at all. Some people say it is girdling, banding or squeezing, as if 'a tight band' or constricting pain is around the trunk of the body. The "pins and needles" sensation often fits into this category.
A specific type of dysesthesias is known as the MS Hug. It can be felt anywhere on the torso, encircling the body. It can be sharp or dull, burning or tickling, tingling, crushing or constricting, or even simply characterized by numbness. The "hug" can be constant or intermittent, lasting a few minutes, hours, or even days.
Parasthesia is similar, or maybe even the same, as dysesthesias, described as pins and needles, tingling, buzzing or vibrating. It ranges from simply annoying to intense and painful.
LHermitte's (also spelled l'Hermitte's)Sign is a sudden brief, stabbing, electric-shock-like sensation that runs from the back of the head down the spine and goes into arms or legs. It is triggered by bending the neck forward, often after a cough or sneeze.
Trigeminal neuralgia (TN) is also known as tic doloureux which is French for "painful twitch." It sounds almost cute in French, and its translation sounds cute, too, but TN is anything but cute. It is recognized as the most intensely painful MS symptom; in fact, it is considered it the most painful affliction known to medical practice. It is caused by actual damage to the trigeminal nerve and is described as a stabbing pain, sharp pain, burning, or as I describe it, electrocution.
It is triggered by chewing, brushing teeth, touching the cheek, or even breathing. Tic doloureux is also known as "the suicide disease."
Optic Neuritis is a common MS symptom, often the initial one. It can be accompanied by pain when the eyes are moved. The pain usually lasts only a few days and often subsides when the vision is still affected. This pain occurs when the nerve is actually inflamed.
Tonic spasms are painful spasms that cause legs or arms to move unexpectedly or jerk, and usually last for only seconds. These spasms may also result in stiff or rigid muscles or limbs.
All of these are well documented incidences of neuropathic pain. There are many other types that individual experiences that have not been listed. For example, some people feel as if they are impaled by sharp objects. It's obvious there are no sharp objects, but the feeling is quite clear. I have read about -- and felt -- burning nails or needles on the feet.
MS is a confusing disease. There seems to be no distinct categories when describing anything about this condition. The names of the pain types are different, but many of them have the same or similar sensations or descriptions. Dr. Bethoux tells us "It's very distressing for patients because they have a hard time explaining what their pain experience is."
I'm sure there are other sensations -- burning, pressure, constriction, intensive temperature sensations, or others -- that fit into this category. If you have one, please let me know.
Next time I'll talk about musculoskeletal pain.
Notes and Links
Julie Stachowiak - Overview of Pain