Nociplastic Pain
Musculoskeletal conditions can cause not only localised pain as a direct result from the condition, but also chronic widespread pain. This phenomenon has many terms with subtle differences in meaning, including central sensitisation, and nociplastic pain.[1]
Central sensitisation is found in 10 to 40 percent of those with osteoarthritis, rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, and systemic lupus erythematosus. It is also common in chronic trauma-induced low back and neck pain, complex regional pain syndrome, joint hypermobility syndrome, lateral elbow tendinopathy, and carpal tunnel syndrome. It is also thought to be a pain mechanism in fibromyalgia and other related chronic pain conditions, such as irritable bowel syndrome, bladder pain syndrome, and temporomandibular dysfunction.[1]
Epidemiology
The prevalence of chronic pain in New Zealand, when defined as lasting for 6 months or longer, was measured at 16.9% in 2011. Prevalence increased with age and economic deprivation. Pacific and Asian peoples had lower rates of chronic pain than European/other.[2] Around one fifth of people with chronic pain have predominantly neuropathic pain.[citation needed] Neuropathic pain is more disabling than other forms of pain and is associated with a lower quality of life.[citation needed]
Definitions
The IASP definitions of pain can be found on their website.
- IASP Definition of Pain
The IASP definition of pain was recently updated in 2020.[3]
“An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”
—IASP Definition of Pain 2020
- Sensitisation
Increased responsiveness of nociceptive neurons to their normal input, and/or recruitment of a response to normally subthreshold inputs...a neurophysiological term, may only be inferred indirectly from phenomena such as hyperalgesia or allodynia
- Central Sensitisation
Woolf discussed the differences between pain versus pathology versus "pain syndromes."[4] The central component of post-injury pain hypersensitivity was first termed sensitisation in 1987.[5]
“Any sensory experience greater in amplitude, duration and spatial extent than that would be expected from a defined peripheral input under normal circumstances qualifies as potentially reflecting a central amplification due to increased excitation or reduced inhibition. These changes could include a reduction in threshold, exaggerated response to a noxious stimulus, pain after the end of a stimulus, and a spread of sensitivity to normal tissue”
—Woolf 2011
The IASP define central sensitisation as follows:
“Increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input.”
—IASP
- Peripheral sensitisation
Increase Responsiveness and reduced threshold of nociceptive neurons in the periphery to the stimulation of their receptive fields
- Nociceptive Pain
actual or threatened damage , non-neural tissue, activation of nociceptors.
- Neuropathic pain
Primary lesion or disease of the somatosensory nervous system.
Pain Mechanisms
Some patients with fibromyalgia actually have unrecognised small-fibre polyneuropathy (SFPN). Oaklander et al found SFPN in 41% of skin biopsies of patients diagnosed with fibromyalgia, compared to 3% of controls. This is a disease that causes dysfunction and degeneration of peripheral small-fibre neurons.[6]
Anatomical and Functional Changes
Clinical Features
Diagnosis
Management
Prognosis
- Osteoarthritis: In patients with osteoarthritis of the knee or hip who undergo joint replacement, chronic widespread pain (CWP) correlates with poorer pain outcomes, and increased analgesic use.[1]
- Autoimmune and inflammatory rheumatological conditions: CWP is correlated with increased pain and worse outcomes when measured by self-report questionnaires.[1]
- Chronic low back pain: CWP is present in 25% of patients, and correlated with greater disability.[1]
- Chronic neck pain: CWP at one month post neck injury is correlated with poor outcomes at 6 months.[1]
- Carpal tunnel syndrome: worse outcomes with CWP[1]
- Shoulder pain: worse outcomes with CWP[1]
- Lateral elbow tendinopathy: Worse outcomes with CWP[1]
Key Articles
- {{#l:Cohen2016 - nociplastic pain third mechanistic descriptor.pdf}}
- {{#l:Woolf2011 - Central sensitisation.pdf}}
- {{#l:Woolf2014 - Nociceptive amplification naming.pdf}}
- {{#l:Yunus2008 - Central sensitivity syndrome.pdf}}
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Goldenberg, D et al. Overview of chronic widespread (centralized) pain in the rheumatic diseases. In: UpToDate, Post, TW (Ed), UpToDate, Waltham, MA, Jan 23 2020.
- ↑ Dominick et al.. Patterns of chronic pain in the New Zealand population. The New Zealand medical journal 2011. 124:63-76. PMID: 21946879.
- ↑ International Association for the Study of Pain (2020) IASP’s New Definition of Pain. Available at: https://www.iasp-pain.org/PublicationsNews/NewsDetail.aspx?ItemNumber=10475 (accessed 27 July 2020).
- ↑ Woolf. Central sensitization: implications for the diagnosis and treatment of pain. Pain 2011. 152:S2-15. PMID: 20961685. DOI. Full Text.
- ↑ Woolf et al.. Prolonged primary afferent induced alterations in dorsal horn neurones, an intracellular analysis in vivo and in vitro. Journal de physiologie 1988. 83:255-66. PMID: 3272296.
- ↑ Oaklander et al.. Objective evidence that small-fiber polyneuropathy underlies some illnesses currently labeled as fibromyalgia. Pain 2013. 154:2310-6. PMID: 23748113. DOI. Full Text.
