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does SCI/neuro pain change pain thresholds

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    does SCI/neuro pain change pain thresholds

    Does nerve pain (and treatment) change the way your brain percieves other (ie 'real') pain.

    For example I take endep and voltaren which in combination make nerve pain and sensations manageable for me on a day to day basis. But when I have 'real' injuries to other parts of my body not related to the SCI I wonder sometimes whether they hurt more or less than they should (and how seriously I should take them).

    #2
    I believe there is quite a bit of writing that chronic pain does change the body. If I remember correctly, people may become more sensitive to pain.

    I've read about opioids increasing pain in some people. I do not recall reading the same about volteren, and not endep.

    Here's one article:

    http://cme.medscape.com/viewarticle/481798

    Brain Plasticity and Central Sensitization

    Central sensitization describes changes that occur in the brain in response to repeated nerve stimulation. Following repeated stimulation, levels of neurotransmitters and brain electrical signals change as neurons develop a "memory' for responding to those signals. Frequent stimulation results in a stronger brain memory, so that the brain will respond more rapidly and effectively when experiencing the same stimulation in the future. The resulting changes in brain wiring and response are referred to as nerve plasticity (describing the ability of the brain to change easily) or central sensitization. Thus, the brain is activated or sensitized by previous or repeated stimuli to become more excitable.
    The changes of central sensitization occur after repeated experiences with pain. Research in animals shows that repeated exposure to a painful stimulus will change the animal's pain threshold and result in a stronger pain response. Researchers believe that these changes may explain the persistent pain that can occur even after successful back surgery. Although a herniated disc may be removed from a pinched nerve, pain may continue as a memory of the nerve compression. Newborns undergoing circumcision without anesthesia will respond more profoundly to future painful stimuli, such as routine injections, vaccinations, and other painful procedures. These children have not only a greater hemodynamic response (tachycardia and tachypnea), but increased crying as well.
    This neural memory of pain has been studied extensively. In a review of his earlier studies, Woolf[1] noted that the enhanced reflex excitability after peripheral tissue damage does not depend on continuing peripheral input; rather, hours after a peripheral injury, spinal dorsal horn neuron receptive fields continued to expand. Investigators have also documented the importance of the spinal NMDA receptor to the induction and maintenance of central sensitization.[2]

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      #3
      Hi L2R,
      I would echo what TAM63 has brought up. I have heard that there are physical and radiographic changes in the brain that can be demonstrated by MRI with repeated painful stimuli. In my study of one (myself), I feel that my pain threshold has been lowered. I have put up with a level of constant pain so long that I don't have the endurance to manage more. It is like the straw that breaks the camel's back (what a fitting analogy for SCI ! ) This may be more of a psychological phenomenon but I guess all psychological processes can be reduced to physical processes....
      Again, just an observation of myself. I know I used to have a high threshold for pain and honestly, if you could graft my neuro pain as I sit here writing this to some able bodied person, as for as I know they may be wondering what the hell is wrong with them and dialing 911.

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        #4
        I just had an apicoectomy (peel back gum, drill through jaw bone, cut off roots of tooth). For various reasons I dreaded having this done.
        I have a decreased tolerance for pain since being injured (and dealing with constant neuro pain).
        Rich

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          #5
          Rich - any sane person would dread having that procedure done!

          I think you guys are right. Today my legs are buzzing like hell, my foot is burning and my bladder has gone bizurk so all of a sudden I feel old and worn out - my good foot is aching all the way through the arch and into the toes. So I worry that there is something going on but perhaps its just the neuro pain wearing me out. Ho hummm..... unfortunately I have also run out of anything stronger than the Endep and Voltaren. Did someone say that upping the dose of Endep can help on bad days? (I normally just take 10mg which does the trick but not doing much tonight).

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            #6
            I sometimes think my glass of pain is full and one more drop of pain puts me over the edge. Other times, on days when I am having a good day, sometimes i think I am more pain tolerent than I used to be, perhaps because I have less sensation or numbness in parts of my body or maybe becuase the pain meds cover up the additional pain.
            2012 SCINetUSA Clinical Trial Support Squad Member
            Please join me and donate a dollar a day at http://justadollarplease.org and copy and paste this message to the bottom of your signature.

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              #7
              I don't think it has lowered mine, i did a laminectomy and Stime revision with a small local and "dealt" with the rest and have broken several bones with no increase over pre SCI
              Kindly,

              The Ketamine Kitty

              All the tears, all the pain, all the rage through the night (apolgies to the rewrite) RR

              Next time I die make sure I'm gone,
              don't leave 'em nothing to work on JT

              And I ain't nothin but a dream JM

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                #8
                Originally posted by swh2007 View Post
                I sometimes think my glass of pain is full and one more drop of pain puts me over the edge. Other times, on days when I am having a good day, sometimes i think I am more pain tolerent than I used to be, perhaps because I have less sensation or numbness in parts of my body or maybe becuase the pain meds cover up the additional pain.
                I totally agree. I know I am tired out with the 8 year 'fight' of daily pain, and any new pain experience is like the straw that breaks the camels back. So I think it has lowered my threshold. But at the same time, I know that if an AB felt what I felt from the waist down with the burning and electric shocks, they would be crying to their mother and dialing 911!

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                  #9
                  Pain sucks.
                  2012 SCINetUSA Clinical Trial Support Squad Member
                  Please join me and donate a dollar a day at http://justadollarplease.org and copy and paste this message to the bottom of your signature.

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                    #10
                    I was asked to go to the dentist and I went and had a good checkup. They wanted to do more work and I couldn't stand the thought of more pain than I already have. I definitely avoid pain and try to keep myself as comfortable as possibe. I do cardio in 10 minute bursts. I also like to take breaks from moving way more often than I did pre injury.

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                      #11
                      The textbooks call this "delay with overshoot".

                      It is a matter of timing and threshold

                      The classic clinical sign of spinothalamic injury (which is what most SCI central pain people have) is "delay with overshoot".

                      It is not a time delay, but a threshold delay. It means that at first you are less likely to perceive pain, but when it hits, it overshoots so that the pain is more severe. This is most easily demonstrated with an open safety pin (which is felt immediately since there is an allodynic response to sharpness in CP), where it feels VERY sharp right at the first. By comparison, if you step on a nail in a board, it is going to go deeper into your foot than normal before you realize you have been punctured. I have very severe allodynia to sharpness, but I stepped on a nail and it went right through my foot before I realized I had been injured.

                      CP people also have a reduced response to temperature difference. The typical person can tell one or two degrees, sometimes up to four degrees depending on what temperature conditioning* the skin is under, and a CP person requires as much as nine degrees to detect a temperature difference. Yet, once the difference has been perceived, if it is cold, it has the power to evoke the burning. This has been considered to be a variant of the "delay with overshoot" response.

                      This phenomenon is "delay with overshoot" and is the equivalent of damage to the spinothtalamic tract, presumably the anterior spinothalamic tract specifically.


                      **temperature conditioning" refers to what the ambient temperature is, how long the skin has been exposed to it, and how near the noxious level the temperature is. A warmed skin will be more sensitive to a change in cold than one which is already cooled.

                      Caloric testing is almost never done, except experimentally, but all of you with CP have changes. You just don't know it.
                      Last edited by dejerine; 6 Apr 2010, 3:36 AM.

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                        #12
                        OK well I went and got my foot checked out... just in case... nothing major but apparently is quite a painful thing (something called siesmoiditis - excuse my spelling, basically irritation of the little bones in the ball of your foot and the tendons) so not my imagination but nothing thats going to kill me either. Still really don't have a clue where my pain thresholds are though, but I can get out on the bike and sit on threshold heartrate through a 40 minute timetrial which certainly doesn't tickle. But its a different (and yes, almost good) sort of pain and does a good job of covering up the neuro type pain.

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