Fibromyalgia pain is complex and involves multiple dysfunctions in how the body processes signals. One of these processing dysfunctions deals with something called pain inhibition.
In most people, sustained or repeated pain is perceived as diminishing. For example, when they put on a tight pair of pants, it may be a little painful at first, but then the pain fades away. If the dentist pokes at healthy gums multiple times, the first poke will hurt the worst and subsequent ones will hurt less.
That's because pathways in the brain and spinal cord kick in to block the sensation of pain. They inhibit pain signals. It's like your body is saying, "That hurts. You clearly understand that by now, so I'll just turn down the intensity a little for you."
However, a growing body of evidence shows that this system doesn't function properly in people with fibromyalgia. The result is that your waistband keeps hurting you all day, and each poke from the dental tool is as painful as the first. This is part of what's often described as your body "turning up the volume" of pain.
The Lack of Pain Inhibition
We don't fully understand fibromyalgia pain and the role played by this lack of inhibition. However, it's possible that it not only contributes to our overall pain load, but could actually play a role in sustaining the illness.
Two studies published in early 2012 support this view and contribute to our understanding of dysfunctional inhibition in this condition:
- In a study in The Clinical Journal of Pain comparing levels of pain inhibition in fibromyalgia patients, irritable bowel syndrome patients, and healthy people, researchers noted an absence of pain inhibition in those with fibromyalgia accompanied by abnormal responses in the autonomic nervous system.
- A study published in Molecular Pain used functional MRI (fMRI) to look at connectivity between parts of the brain in fibromyalgia. The fMRI revealed that the participants with fibromyalgia had reduced connectivity in the brain's inhibitory network, which involves the amygdala, hippocampus and brainstem.
Researchers from the second study add that their work could lead to the clinical use of fMRI to provide doctors with an objective measure of pain dysregulation. A measurement like that could help doctors diagnose and treat fibromyalgia more effectively.
A key feature of fibromyalgia is hyperalgesia, which is when the nervous system intensifies pain signals. Research suggests that problems with pain inhibition contribute to hyperalgesia.
Living With Dysregulated Pain Inhibition
In order to live with the extra pain load added by dysregulated pain inhibition, you may want to make some changes.
Many people with fibromyalgia pay special attention to the way they dress to avoid tight or scratchy clothing. It may also help to anticipate situations that could cause pain, such as dentist appointments and mammograms, and take pain medication before you go.
Learn more about fibromyalgia pain:
Bergmer M, et al. European journal of pain. 2012 May;16(5):636-47. doi: 10.1002/j.1532-2149.2011.00058.x. Cerebral mechanisms of experimental hyperalgesia in fibromyalgia.
Ceko M, Bushnell MC, Gracely RH. Pain research and treatment. 2012;2012:585419. Neurobiology underlying fibromyalgia symptoms.
Chalaye P, et al. The Clinical journal of pain. 2012 Jul;28(6):519-26. Comparing pain modulation and autonomic responses in fibromyalgia and irritable bowel syndrome patients.
Ge HY, et al. European journal of pain. 2012 Feb;16(2):196-203. doi: 10.1016/j.ejpain.2011.06.008. Descending pain modulation and its interaction with peripheral sensitization following sustained isometric muscle contraction in fibromyalgia.
Jensen KB, et al. Molecular pain. 2012 Apr 26;8(1):32. Patients With Fibromyalgia display Less Functional Connectivity in the Brain's Pain Inhibitory Network.
Staud R. Clinical and experimental rheumatology. 2011 Nov-Dec;29(6 Suppl 69):S109-17. Brain imaging in fibromyalgia syndrome.