Many people living with chronic pain and multiple sclerosis (MS) often experience pain that has a combination of nociceptive, nociplastic, and / or neuropathic pain characteristics. This is evident from the study results published in Pain.
There is limited data describing pain subtypes and underlying mechanisms in patients with MS and chronic pain. Consequently, the study researchers attempted to examine the distribution of neuropathic, nociceptive, nociplastic, and mixed pain in patients with MS and chronic pain. In addition, they aimed to identify differences between pain subtypes and to compare the use and pain relief of traditional pharmacological analgesics.
This national web-based survey interviewed 842 adults with a self-reported diagnosis of MS (mean age 51.83 ± 11.98) on various pain characteristics. This included measurements of the neuropathic pain with the painDETECT, of the nociplastic pain with the fibromyalgia assessment criteria and the pain intensity with the PROMIS pain intensity.
The survey also included measures to screen for three common chronic overlapping pain conditions, including migraines, pelvic pain, and TMD. The respondents also answered questions about the use of pain relievers and the associated pain relief.
About 41% of respondents reported having nociceptive pain, while 27% of respondents reported having mixed neuropathic / nociplastic pain. In addition, 23% reported having nociplastic pain and 9% had neuropathic pain.
Each pain subtype differed significantly in PROMIS pain intensity T-scores (P <0.001). The nociceptive type showed the lowest (mean 44.98 ± 6.89) and the mixed neuropathic / nociplastic type showed the highest (mean 55.06 ± 5.77) pain intensity. All pain subtypes differed significantly in terms of pain intensity values (P <0.001 for all), with the exception of the neuropathic subtypes compared to nociplastic subtypes (P = 0.99).
The most common drugs used for analgesia in all types of pain were nonsteroidal anti-inflammatory drugs (NSAIDs) [66.5%]). Steroids were the least common (6.5%). The relief scores for cannabinoid-based analgesics were significantly higher in subjects with mixed pain than in subjects with neuropathic pain (P = 0.02). The relief scores for NSAIDs were significantly higher in subjects with nociceptive pain than in subjects with nozplastic pain (P = 0.001) and mixed pain (P <0.001) and in subjects with non-plastic pain than in subjects with mixed pain (P = 0.04)).
Limitations of the study were the inclusion of predominantly female and white respondents, the use of the National MS Society listerv to recruit patients, and the lack of available measures to identify nociceptive pain.
The study’s researchers concluded that “this work highlights the need to assess the pain phenotype in individuals with chronic pain and MS in order to move to a precision model of pain management in MS.”
Kratz AL, Whibley D., Alschuler KN, et al. Characterization of chronic pain phenotypes in multiple sclerosis: a nationwide survey study. Published online November 3, 2020. Pain. doi: 10.1097 / j.pain.0000000000002136