Pain in Parkinson's Disease: From the Pathogenetic Basics to Treatment Principles

Pain syndromes are quite common in Parkinson's disease, in addition to the motor defect, can significantly worsen the quality of life. Various types of pain related to PD have been described. Different clinical characteristics of the pain, variable relationship with motor symptoms, and variable response to dopaminergic drugs, as well as, in some cases, the dependence its appearance in a specific time of the day, suggest that pain in PD has a complex mechanism with the widespread impairment of the sensory information transmission at different levels of the CNS. In addition to the dopaminergic systems of the brain and spinal cord, nondopaminergic systems (nor epinephrine, serotonin, gamma-amino butyric acid, glutamate, endorphin, melatonin) are also involved in the development pain syndromes in PD. A neurodegenerative process associated with PD establishes a new dynamic balance between the nociceptive and antinociceptive systems, which ultimately determines the level of pain susceptibility and the pain experience characteristics. Basal ganglia along with amygdala, intralaminar nuclei of the thalamus, insula, prefrontal cortex, anterior and posterior cingulate cortex determine the motor, emotional, autonomic and cognitive responses to pain.