Chronic Pain and Neurological Disorders

Urban Spine and Joint

In the United States, 1 in 5 adults suffers from chronic pain [1]. Women, unemployed and impoverished adults, and rural residents are more likely to experience this condition, especially with increasing age [2]. Chronic pain includes many subtypes, including (A) primary chronic pain, characterized by pain in one or more regions without an underlying condition that persists for longer than 3 months and is associated with disability and emotional distress, as in fibromyalgia, irritable bowel syndrome (IBS), and other conditions commonly labeled as widespread pain (WSP); (B) cancer pain; (C) headache and orofacial pain; (D) visceral pain; (E) musculoskeletal pain; and (F) post-surgical and post-traumatic pain [3]. In many cases, pain caused by an injury or illness is still perceived by nerves and pain receptors, even if the causal condition has healed. One of the most common reasons adults seek medical care, chronic pain is correlated with mobility restrictions, opioid dependence, depression, and reduced quality of life [4]. Additionally, recent studies have demonstrated a link between chronic pain and neurological disorders later in life [5].

Widespread pain (WSP) is one of the most common chronic pain syndromes. Characterized by persistent pain in all four body quadrants, WSP is associated with central nervous system (CNS) dysfunction, such as sensory processing issues, enhanced nerve excitation, and neurotransmitter imbalance [6]. While studies have already demonstrated a link between WSP and cardiovascular disease, cancer, and mortality, researchers continue to investigate the connection between widespread chronic pain and neurological disorders such as dementia [5]. Although previous studies focused on establishing the relationship between WSP and dementia have been limited by a lack of data and insufficient time, one recent study utilizing retroactive data review and a 18-year time frame presents strong evidence for an association [5]. WSP was linked to a 43% higher risk of dementia, 47% higher risk of Alzheimer’s disease, and 29% higher risk of stroke; additionally, for patients over 65, the risk of stroke increased to 54% [5]. The researchers explored three different reasons for this association, including the possibility that WSP directly affects cognitive function, the hypothesis that WSP is a preclinical stage of dementia and Alzheimer’s disease, as well as the idea that lifestyle factors associated with WSP may inadvertently lead to neurological disorders [5]. The presentation of these hypotheses will ideally lead to more research in the future.

Although the 50 million Americans suffering from chronic pain often have limited control over their condition, certain lifestyle adjustments may help reduce the pain, avoid deleterious side effects and curb the development of secondary conditions [7]. Physical therapy, healthy eating, exercise, manageable stress levels, and a normal BMI may aid in reducing the symptoms and longevity of chronic pain [8]. However, these factors may be difficult for patients with chronic pain; therefore, healthcare professionals should work closely with their patients to create manageable plans to improve their quality of life and reduce the impact of symptoms associated with pain, such as neurological conditions.

References

1: Dahlhamer, D., Lucas, J., Zelaya, C., Nahin, R., Mackey, S., DeBar, L., Kerns, R., Von Korff, M., Porter, L., and Helmick, C. (2018). Prevalence of chronic pain and high-impact chronic pain among adults — United States, 2016. Morbidity and Mortality Weekly Report 2018, vol. 67. DOI: 10.15585/mmwr.mm6736a2.

2: Smith, B., Elliott, A., Chambers, W., Smith, W., Hannaford, P., and Penny, K. The impact of chronic pain in the community. Journal of Family Practice, vol. 18. DOI: 10.1093/fampra/18.3.292.

3: Treede, R., Rief, W., Barke, A., Aziz, Q., Bennett, M., Benoliel, R., Cohen, E., Evers, S., Finnerup, N., First, M., Giamberardino, M., Kosek, E., Lavand’homme, P., Nicholas, M., Perrot, S., Scholz, J., Schug, S., Smith, B., Svensson, P., Vlaeyen, J., and Wang, S. (2015). A classification of chronic pain for ICD-11. Journal of Pain, vol. 156. DOI: 10.1097/j.pain.0000000000000160.

4: Gureje, O., Von Koeff, M., Simon, G., and Gater, R. (1998). Persistent pain and well-being: a World Health Organization study in primary care. JAMA Network, vol. 280. DOI: 10.1001/jama.280.2.147.

5: Wang, K. and Liu, H. Association between widespread pain and dementia, Alzheimer’s disease and stroke: a cohort study from the Framingham Heart Study. Regional Anaesthesia and Pain Medicine, vol. 46. DOI: 10.1136/rapm-2021-102733.

6: Sluka, K. and Clauw, D. (2016). Neurobiology of fibromyalgia and chronic widespread pain. Neuroscience, vol. 338. DOI: 10.1016/j.neuroscience.2016.06.006.

7: Mills, S., Nicolson, K., and Smith, B. (2019). Chronic pain: a review of its epidemiology and associated factors in population-based studies. British Journal of Anaesthesia, vol. 123. DOI: 10.1016/j.bja.2019.03.023.

8: Hecke, O., Torrance, N., and Smith, B. (2017). Chronic pain epidemiology and its clinical relevance. British Journal of Anaesthesia, vol. 111. DOI: 10.1093/bja/aet123.