Evidence for the role of spinal cord systems in Parkinson's disease-associated pain.

A patient with Parkinson's disease had severe levodopa-associated leg pain in a beginning-of-dose and peak-dose pattern. Local anesthetic block of the lumbar sympathetic chain or differential epidural block did not alter the pain. Spinal anesthesia abolished the pain. We postulate that levodopa-associated pain in Parkinson's disease either originates in or is mediated by spinal cord dopaminergic systems.