Thursday, August 08, 2013

Melzack & Katz, Pain. Part 19c: Implications of the Neuromatrix concept - fibromyalgia.

The paper, Pain.

Part 19: Implications of the Neuromatrix concept - phantom pain Part 19bImplications of the Neuromatrix concept - low back pain.


The third of Melzack and Katz' "Implications" section is about fibromyalgia, another huge topic... 
This is the last blogpost before we reach the conclusion. 

3. Fibromyalgia

"Fibromyalgia affects 2% of the population, afflicts more females than males (7:1), and reflects the complexity of most chronic pain syndromes.80
Reference 80 goes to Bennett R. Fibromyalgia. In: Melzack RWall PD, eds. Handbook of Pain Management. Edinburgh: Churchill Livingstone; 200395108.

Look back at the blogpost on Women, pain and stress for more about this enormous gender gap. 
"The major features of fibromyalgia are multiple tender areas (‘trigger points’) of the skin and muscles, ‘aching all over,’ increased skin sensitivity to almost every kind of stimulation, major sleep disturbances, and several indices of abnormal functioning of the whole stress-regulation system."
While it's true that people with FM have tender points, the presence of tender points as a diagnostic criterion for FM has been deconstructed by the very same doctor who has been grappling with the diagnostic problem for decades, Fred Wolfe. See this interview


Check out his recently published blog, The Fibromyalgia Perplex on the history of tender point evaluation, Tender Points.  
You won't be disappointed. Be sure to read the comment section where John Quintner puts in an appearance. 
Then read all his blog entries for February of this year. The one titled Travell, Simons, and Cargo Cult Science is particularly delicious.

Back to Melzack and Katz: 
"An understanding of fibromyalgia has eluded us because we have failed to recognize the role of stress mechanisms in addition to the obvious sensory manifestations which have dominated research and hypotheses about the nature of fibromyalgia. Melzack's interpretation of the available evidence is that the body-self neuromatrix's response to stressful events fails to turn off when the stressor diminishes, so that the neuromatrix maintains a continuous state of alertness to threat. It is possible that this readiness for action produces fatigue in muscles, comparable to the fatigue felt by paraplegics in their phantom legs when they spontaneously make cycling movements.24 "
Well, maybe.. 
 "It is also possible that the prolonged tension maintained in particular sets of muscles produces the characteristic pattern of tender spots."
Well, maybe... 

Maybe both at the same time. Prolonged tension in muscles could a) give rise to trophic changes in tissues, as a result of b) mechanical deformation on neural tissue which c) could ostensibly lead to annoyance signalling barrage from nociceptive-capable thin-C afferents inside nerves themselves, i.e. nervi nervorum, whose main job is to provide trophic support to neural container tissue, but who might kvetch if the mechanical or biochemical "melieu interior" goes off normal for any extended period of time, such as would result if a nerve were tensioned long enough to affect its inner vascular supply or drainage (see Lundborg)...  Enough tension for long enough could even starve/kill off neurons, maybe. 

Or make more of them grow? 

See Skin Abnormality May Prove Biological Basis For Fibromyalgia.
I don't like the clunky title but I think it's interesting that there is supposedly some sort of association with a higher density of sensory neurons in blood vessel walls [in hands] but no other kind present. I'd love to see what the sensory array is in non-glabrous tissue. However, since hands take up so much real estate inside the S1M1 cortex, maybe these people are onto something quite relevant to the neuromatrix concept. 


See the paper itself, Albrecht PJ, Hou Q, Argoff CE, Storey JR, Wymer JP, Rice FL. Excessive Peptidergic Sensory Innervation of Cutaneous Arteriole-Venule Shunts (AVS) in the Palmar Glabrous Skin of Fibromyalgia Patients: Implications for Widespread Deep Tissue Pain and Fatigue. Pain Med. 2013 Jun;14(6):895-915. 

EDIT AUG 10: Oaklander et al. recently published Objective evidence that small-fiber polyneuropathy underlies some illnesses currently labeled as fibromyalgia. Here is part of the abstract: 
"We found that 41% of skin biopsies from subjects with fibromyalgia vs 3% of biopsies from control subjects were diagnostic for SFPN, and MNSI and UENS scores were higher in patients with fibromyalgia than in control subjects (all P0.001). Abnormal AFTs were equally prevalent, suggesting that fibromyalgia-associated SFPN is primarily somatic. Blood tests from subjects with fibromyalgia and SFPN-diagnostic skin biopsies provided insights into causes. All glucose tolerance tests were normal, but 8 subjects had dysimmune markers, 2 had hepatitis C serologies, and 1 family had apparent genetic causality. These findings suggest that some patients with chronic pain labeled as fibromyalgia have unrecognized SFPN, a distinct disease that can be tested for objectively and sometimes treated definitively."
In English, it means that almost half the people with diagnosed FM sampled had unusual C-fibre array in the skin. Probably elsewhere too, but the samples taken were skin biopsies.  SFPN means small fibre polyneuropathy. Here is a news story about this paper. Study Finds Evidence of Nerve Damage in Around Half of Fibromyalgia Patients. It sounds like there could be quite a variety of disorders, some of which correlate to neural structure, or blood chemistry profiles, all lumped together under the FM umbrella. Or it could mean nothing. Time will tell.

Back to Melzack & Katz:
"The abnormal neural program of prolonged, centrally maintained alertness may produce a generalized state of perceptual vigilance or ‘open sensory gates’ to receive information for rapid response to threat. The persistent low-level stress (i.e., the failure of the stress response to cease) would produce anomalous alpha waves during deep sleep, greater feelings of fatigue, higher generalized sensitivity to all sensory inputs, and a low-level, sustained output of the stress-regulation system, reflected in a depletion of circulating cortisol.
Maybe it's stressful for a CNS to try to make sense out of signalling that it expected would be proportioned normally, but turns out, isn't.. Could it be that fibromyalgia might be (at least in part) yet another neurocristopathy

"The results of a recent study81 of Hatha yoga for women with fibromyalgia support these suggestions and provide some hope for those afflicted with this demoralizing disease. At the end of an eight-week Hatha yoga program, continuous pain and pain catastrophizing decreased while chronic pain acceptance, levels of mindfulness, and cortisol levels increased (i.e., normalized).
Reference 81 goes to Curtis KOsadchuk AKatz J. An eight-week yoga intervention is associated with improvements in pain, psychological functioning and mindfulness, and changes in cortisol levels in women with fibromyalgia. J Pain Res 4:189201. (Full text!)

There is definitely something to be said for learning how to be introspective about interoception. Yoga is brilliant for setting up conditions for that to occur. Focus, attention to breath, attention to relationship to gravity, learning how to depend on it, sink into it.. attention to scanning the entire inner space as it relates to outer space, learning to do all these things at once. Gives one access to one's own hard drive. A sense of mastery of these things, regardless of how they "feel", learning how fast that changes, how ephemeral "sensation" is. Learning to be detached from an old way of sensing, sensation coming at you - by focusing on new ways of sensing, by bravely going where you have never gone before, right into sensing. Deliberately. Carefully. Like an explorer in new territory. It messes with learning and what has been stored in the hippocampus. It shakes things up, cognitively/evaluatively speaking. Plus you do learn how to pay close and sustained attention to one set of "things", and screen out everything else that might be going on on the entire planet. Coming to terms with physical existence, regardless of what kind of physicality you may have ended up with. [I recommend learning yoga all by yourself, from a book, not in a group. No outside influence until you have already got your bearings.]

"Goldenberg et al.82 described striking similarities between fibromyalgia and chronic fatigue syndrome, and note that the frequent reports by patients in both groups that the onset of fibromyalgia or chronic fatigue syndrome was preceded by a flu-like or viral illness suggests an immune system abnormality."
Reference 82 goes to Goldenberg DLSimms RWGeiger AKomaroff AL. High frequency of fibromyalgia in patients with chronic fatigue seen in a primary care practice. Arthrit Rheumat 199033:381387.
"However, a large proportion of patients (about 45%) do not report a flu-like illness but instead report a preceding accident, surgical operation, or no apparent cause. This suggests that an abnormal, partially genetically determined mechanism fails to turn off the stress response to viral, psychological, or other types of threat to the body-self."
My bold. 
Sounds like some sort of miscommunication or misunderstanding might crop up between critter brain and human brain, somewhere deep inside the brain, then develops, and this becomes its own stressor. 

I should think the implications of the neuromatrix concept for fibromyalgia would be quite large, given how this "syndrome" (which, I've been told, is really just doctor code for "don't have a clue") has been a diagnosis of exclusion, and unfair "patient-must-be-crazy"-ism. Meanwhile, there is yoga, but really, any kind of movement helps, according to any literature I've heard about, and not much else does. 

Next up, we conclude this voyage through Melzack and Katz' paper, and debark! 

Almost there. 

Previous blogposts

Part 1 First two sentences

Part 2 Pain is personal Also Pain is Personal addendum., Neurotags! Pain is Personal, Always.

Part 3a Pain is more than sensation: Backdrop Part 3b Pain is not receptor stimulation Part 3c: Pain depends on everything ever experienced by an individual

Part 4: Pain is a multidimensional experience across time

Part 5: Pain and purpose

Part 6a: Descartes and his era; Part 6b: History of pain - what’s in “Ref 4”?; Part 6c: History of pain, Ref 4, cont.. : There is no pain matrix, only a neuromatrix; Part 6d: History of Pain: Final takedown Part 6e: Pattern theories in the history of pain Part 6f: Evaluation of pain theories Part 6g: History of Pain, the cautionary tale. Part 6h: Gate Control Theory.

Part 7: Gate control theory has stood the test of time: Patrick David Wall;  Part 7b: Gate control: "The theory was a leap of faith but it was right!"

Part 8: Beyond the gate: Self as mayor Part 8b: 3-ring circus of self Part 8c: Getting objective about subjectivity

Part 9: Phantom pain - in the brain! Part 9b: Dawn of the Neuromatrix model Part 9c: Neuromatrix: MORE than just spinal projection areas in thalamus and cortex Part 9d: More about phantom body pain in paraplegics

Part 10: "We don't need a body to feel a body." Part 10b: Conclusion1: The brain generates its own experience of being in a body Part 10c:Conclusion 2: Your brain, not your body, tells you what you're feeling Part 10d: Conclusion 3: The brain's sense of "Self" can INclude missing parts, or EXclude actual parts, of the biological body Part 10e: The neural network that both comprises and moves "Self" is (only)modified by sensory experience

Part 11: We need a new conceptual brain model! Part 11b: Intro to a new conceptual nervous system Part 11c: Older brain models just don't cut it Part 11d: The NEW brain model!

Part 12: Action! 12b: Examining the motor system, first pass. 12c: Motor output and nervous systems - where they EACH came from Part 12d... deeper and deeper into basal ganglia Part 12e: Still awfully deep in basal ganglia Part 12f: Surfacing out of basal ganglia Part 12g: The Action-Neuromatrix

Part 13: Pain and Neuroplasticity Part 13b: Managing neuroplasticity

Part 14: Side trip out to the periphery! Part 14b: Prevention of pain neurotags is WAY easier than cure Part 14c: PW Nathan was an interesting pain researcher  Part 14d: Brain glia are from neuroectoderm and PNS glia are from neural crest Part 14e: The stars in our headsPart 14f: Gleeful about glia Part 14g: ERKs and MAPKs and pain Part 14h: glia-fication of nociceptive input 14i: molecular mediators large and small Part 14j: Neurons, calling glia (over, do you read?) Part 14k: Glia calling glia, over. Do you read? Part 14l: satellite cell and neuron cell body interactions, and we're outta here!

Part 15: Prevention of neurobiological hoarding behaviour by dorsal horn and DRG glia is easier than clutter-busting after the fact

Part 16: Apples are to fruit as cows are to animals as nociceptive input is to pain

Part 17: The stress of it all Part 17b: Stress and adrenals Part 17c: Women, pain, and stress Part 17d: Stress, aging, and pain Part 17e: Stress and aging, keeping hippocampal dendrites fluffed up Part 17f: Chrousos and Gold and stress Part 17g: Stress conceptualization through the agesPart 17h: Phenomenology and physiology of stress Part 17i: Pathophysiology of stress Part 17j: cortisol, good or bad? Sensitivity to pain traumatization.

Part 18: Multiple determinants of pain 

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