Chronic Pain: Evolution of Clinical Definitions and Implications for Practice

What Do We Know about Nociplastic Pain?

Nociplastic pain is a recently distinguished type of pain, distinct from neuropathic and nociceptive pain, and is well described in the literature. It is often mistaken for central sensitization. Pathophysiology has not been clearly established with regard to alteration of the concentration of spinal fluid elements, the structure of the white and gray matter of the brain, and psychological aspects. Many different diagnostic tools, i.e., the painDETECT and Douleur Neuropathique 4 questionnaires, have been developed to diagnose neuropathic pain, but they can also be applied for nociplastic pain; however, more standardized instruments are still needed in order to assess its occurrence and clinical presentation. Numerous studies have shown that nociplastic pain is present in many different diseases such as fibromyalgia, complex regional pain syndrome type 1, and irritable bowel syndrome. Current pharmacological and nonpharmacological treatments for nociceptive and neuropathic pain are not entirely suitable for treating nociplastic pain. There is an ongoing effort to establish the most efficient way to manage it. The significance of this field has led to several clinical trials being carried out in a short time. The aim of this narrative review was to discuss the currently available evidence on pathophysiology, associated diseases, treatment possibilities, and clinical trials. It is important that physicians widely discuss and acknowledge this relatively new concept in order to provide optimized pain control for patients.

Parameters of anger as related to sensory-affective components of pain

Objectives

Comorbid with chronic pain are negative emotions, anger being particularly salient. To evaluate specific relationships between pain and anger, the present study deconstructed anger into five parameters and dichotomized pain into sensory vs. affective components. Hypotheses were (i) anger parameters would be significantly and positively correlated with affective pain more so than with sensory pain, and (ii) individual parameters would be differentially related to pain components.

Methods

The Anger Parameters Scale (APS) was used to rate five parameters of anger: frequency, duration, intensity, latency, and threshold. Also rated was the physical sensation of pain and the degree of distress from pain. The volunteer sample comprised n=51 chronic pain patients, varying in ethnicity/race and educational level.

Results

Descriptive statistics revealed: APS total M=71.52, SD=16.68, Sensory pain M=6.27, SD=2.15, Affective pain M=5.76, SD=2.28. Sensory and affective pain were highly correlated, r=0.70. APS total was significantly associated with affective pain (r=+0.28) but hardly with sensory pain (r=0.12). Two anger parameters significantly correlated with affective pain: anger frequency (r=+0.30, p<0.05) and anger threshold (r=+0.33, p<0.05). Secondarily, certain educational levels (but not gender and ethnicity/race) were associated with significantly higher APS total scores.

Conclusions

Scores for all variables were in the mid-range. As hypothesized, anger was more strongly correlated with distress/suffering of pain than with physical sensation of pain, though both pain components were closely coupled. Specific findings regarding frequency and threshold imply that being angry often and being oversensitive to provocation are associated with greater distress in this context. In deconstructing anger and dichotomizing pain, the present study extends previous research by elaborating on what aspects of anger are most related to which components of pain. Moreover, certain educational levels with higher levels of anger may need special attention. Further research could examine if treatment of anger might lead to corresponding changes in chronic pain.

Diet/Nutrition: Ready to Transition from a Cancer Recurrence/Prevention Strategy to a Chronic Pain Management Modality for Cancer Survivors?

Evidence for the relationship between chronic pain and nutrition is mounting, and chronic pain following cancer is gaining recognition as a significant area for improving health care in the cancer survivorship population. This review explains why nutrition should be considered to be an important component in chronic pain management in cancer survivors by exploring relevant evidence from the literature and how to translate this knowledge into clinical practice. This review was built on relevant evidence from both human and pre-clinical studies identified in PubMed, Web of Science and Embase databases. Given the relationship between chronic pain, inflammation, and metabolism found in the literature, it is advised to look for a strategic dietary intervention in cancer survivors. Dietary interventions may result in weight loss, a healthy body weight, good diet quality, systemic inflammation, and immune system regulations, and a healthy gut microbiota environment, all of which may alter the pain-related pathways and mechanisms. In addition to being a cancer recurrence or prevention strategy, nutrition may become a chronic pain management modality for cancer survivors. Although additional research is needed before implementing nutrition as an evidence-based management modality for chronic pain in cancer survivors, it is already critical to counsel and inform this patient population about the importance of a healthy diet based on the data available so far.