Modern perspective on the problem of pain in Parkinson’s disease (review)

Parkinson’s disease (PD), considered the second most common neurodegenerative disorder after Alzheimer’s disease, has traditionally been perceived as a condition primarily characterized by motor symptoms. However, pain, as a prevalent non­motor symptom, remains underestimated and often overlooked in clinical practice. Its prevalence ranges from 40 % to 85 %, and in 5 % of patients, it may be the first manifestation of the disease. Several classifications of pain in PD have been proposed, including musculoskeletal, neuropathic, dystonic, akathisic, and nociplastic pain, each based on different approaches: etiological, mechanistic, motor status­based, or pain mechanism­based. However, none of these classifications has been universally accepted. Distinguishing between PD­related and non­PD­related pain is crucial. The issue is further complicated by the presence of multiple pain types in the same patient, the overlap between nociceptive and neuropathic pain manifestations, the comorbidities common in elderly patients, and the impact of depression. On the one hand, these factors highlight the complexity of pain pathogenesis, as pain in PD is closely linked to dopaminergic dysfunction, neuroinflammation, and impaired antinociceptive mechanisms. On the other hand, optimization of dopaminergic therapy often fails to provide the expected analgesic effect, necessitating the exploration of alternative approaches Additionally, heterogeneity in pain assessment scales, evaluation methods, and patient characteristics hinders the comparison of research findings and complicates clinical decision­making regarding pain diagnosis. Although gaps remain in understanding pain mechanisms that require further multidisciplinary research and standardized treatment protocols are lacking, progress in pain classification in PD, along with a personalized approach to diagnosis and therapy, may improve the management of various types of chronic pain and enhance patients’ quality of life.