Many people living with chronic pain and multiple sclerosis (MS) often experience pain featuring a combination of nociceptive, nociplastic, and/or neuropathic pain characteristics, according to study results published in Pain.
Limited data are available describing pain subtypes and underlying mechanisms in those with MS and chronic pain. Consequently, study researchers sought to investigate distribution of neuropathic, nociceptive, nociplastic, and mixed pain in patients with MS and chronic pain. Additionally, they aimed to determine differences between pain subtypes and compare use and pain relief from traditional pharmacologic analgesic treatments.
This national web-based survey queried 842 adults with a self-reported MS diagnosis (mean age, 51.83±11.98) about different pain characteristics. These included measures of neuropathic pain with the painDETECT, nociplastic pain with the Fibromyalgia Survey Criteria, and pain intensity with PROMIS Pain Intensity.
Additionally, the survey included measures screening for 3 common chronic overlapping pain conditions, including migraine, pelvic pain, and temporomandibular disorders (TMD). Respondents also answered questions about pain medication use and associated pain relief.
Approximately 41% of respondents suggested they experienced nociceptive pain, whereas 27% of respondents said they had mixed neuropathic/nociplastic pain. Additionally, 23% said they had nociplastic pain, and 9% had neuropathic pain.
Each pain subtype significantly differed with each other regarding PROMIS pain intensity T-scores (P <.001). The nociceptive type demonstrated the lowest (mean, 44.98±6.89) and the mixed neuropathic/nociplastic type demonstrated highest (mean, 55.06±5.77) pain intensity. All pain subtypes were significantly different from each other for pain intensity scores (P <.001 for all), except neuropathic compared with nociplastic subtypes (P =.99).
The most commonly used medications for analgesia across all pain types were non-steroidal anti-inflammatory drugs (NSAIDs [66.5%]). Steroids were the least commonly used (6.5%). The relief ratings for cannabinoid-based analgesics were significantly higher for individuals with mixed pain than those with neuropathic pain (P =.02). Relief ratings for NSAID were significantly higher for individuals with nociceptive pain than nociplastic pain (P =.001) and mixed pain (P <.001) subtypes, as well as for those with nociplastic pain than those with mixed pain (P =.04).
Limitations of the study were the inclusion of mostly 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 investigators concluded that “this work highlights the need to assess pain phenotype in persons with chronic pain and MS to move toward a precision model of pain management in MS.”
Kratz AL, Whibley D, Alschuler KN, et al. Characterizing chronic pain phenotypes in multiple sclerosis: a nationwide survey study. Published online November 3, 2020. Pain. doi:10.1097/j.pain.0000000000002136