Central Pain in Parkinson’s Disease: A Case Report

Parkinson’s disease (PD) is a neurodegenerative disorder that affects predominately dopamine-producing (“dopaminergic”) neurons in a specific area of the brain called substantia nigra. Symptoms generally develop slowly over years. PD is widely recognized by its motor characteristics; however there are well-described non-motor manifestations such as dementia, major depression, sleep disorder, autonomic dysfunction, and pain. In fact, the estimated prevalence of pain in PD varies widely and can be up to 85% of patients. This may largely reflect musculoskeletal and arthralgias secondary to dystonia. However, it is observed that pain persists in regions unaffected by dystonia, which may involve a commonly overlooked and poorly understood etiology of central pain.

The objective of this study was to discuss a case report of central pain in Parkinson’s disease in an outpatient setting. A 67-year-old-male patient with Parkinson’s disease presented with gradual onset of right upper and lower extremity pain and weakness for 6 months. His pain was increased with emotional stress and was progressively exacerbated as he developed a tremor, rigidity, and bradykinesia within his right hemi body. Trials of multiple analgesics, including short acting opioids and acetaminophen were not successful. His pain only mildly responded to NSAID therapy. His consulting neurologist initiated levodopa-carbidopa at 25/100mg every 3 hours for several months. The intensity of the burning pain in his right upper and lower extremity was decreased by the next clinic visit, and he was maintained on the same dosing schedule for one year. He was later trialed on scheduled pregabalin and tramadol with favorable results. He was thus encouraged to continue his medications, and during a subsequent visit, his pain had significantly resolved. Additionally, his rigidity improved, and he no longer had evidence of a tremor during his following clinic visits. 

In summary, this case illustrates the need for a multidisciplinary approach to better care for Parkinson’s disease patients with central pain, and further studies to identify the pathophysiologic mechanism are needed.

Article by Roger S. Moon, et al, from Cedars-Sinai Medical Center, Los Angeles, CA, USA. 

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Image by raheel MEMON, from Flickr-cc.