Authors reviewed the current landscape of therapeutic interventions for differentiating pain classifications in patients with Parkinson disease, noting the need for further research in pathophysiology-driven treatment.
Pain serves as 1 of the most frequent nonmotor complaints in patients with Parkinson disease (PD), affecting 68% to 95% of patients across all clinical stages. Published in the Journal of Parkinson Disease, researchers highlight that similar to PD, pain is complex and even has different classifications of subtypes within the disease.
While prominent, real-life pain data in PD remains scarce. Researchers sought to provide an overview on pain in PD, including classification, assessment, presentation, and the existing therapy landscape.
As researchers highlighted, today’s classifications of pain in PD include musculoskeletal, radicular/neuropathic, dystonia-related, akathic discomfort/pain, and central pain. Notably, the difference in pain directly related to PD and central pain, which is attributed to “objective pain—processing and pain-perception disturbance within ascending and descending pathways,” was referenced. Most frequently, pain presents as musculoskeletal/nociceptive pain in PD patients, but in nearly half of the PD population, comorbid conditions, such as spine and joint arthrosis, serve as contributors.
In examining how pain is presented and assessed in PD, only 1 questionnaire exists that is specifically calibrated and validated for PD. The questionnaire, called The King’s Parkinson disease pain scale, qualitatively and quantitatively assesses pain, and categorizes pain into 7 different domains, with 14 different subcategories. While promising, researchers say that the lack of awareness on differentiating pain causes many patients to not report symptoms. “Such awareness for pain (which might not be communicated verbally) needs guidelines for the complete team of health care professionals involved,” explained researchers.
When it comes to treating pain in PD, interventions remain a major unmet need as only approximately 50% of those with the disease receive at least some type of pain therapy. In managing pain, researchers recommend that therapy should be optimized to address dopaminergic issues, which has been shown to be effective in 30% of patients with PD.
“Optimized dopaminergic treatment can improve pain related to insufficient dopaminergic supply such as akinesia and/or rigidity, pain due to dopaminergic over-supply such as dyskinesia and/or dystonia, or central pain that is dopamine-sensitive,” wrote the researchers.
However, pain killers were said to be the most widely used in management of pain in PD, with 70% prescribed ibuprofen and 36% diclofenac. While pain relief was reported in nearly two-thirds of patients, the short-term relief provided by these drugs could lead to extended dependency for efficacy, which could prove harmful for those provided with opioids.
“We suggest treatment options for specific PD-associated pain types based on the given or assumed pathophysiology and the available data regarding the efficiency of pharmacological and non-pharmacological treatment options,” the researchers wrote.
In concluding, researchers say that further research is warranted to examine pain in PD to develop specific therapies.
Buhmann C, Kassubek J, Jost WH. Management of pain in Parkinson disease. J Parkinsons Dis. Published online June 15, 2020. doi:10.3233/JPD-202069