ABSTRACT
Despite intensive research activity over many years, the cause of Parkinson's disease (PD) remains unknown. This chapter is a review of our knowledge of the pathology, pathophysiology and aetiology of PD as it relates to our understanding of the clinical presentation and management of the condition. Depletion of the neurotransmitter dopamine is the main neurochemical abnormality in PD. The defect in PD causes disruption to the dopaminergic nigrostriatal projections and interferes with function of the motor circuit of the basal ganglia. The pathological changes of PD include cell loss in a specific distribution, the presence of Lewy bodies in surviving cells, and an undamaged striatum. Lewy bodies are neuronal inclusions found in PD, and occur in all areas of neuronal degeneration, including the cortex. Lewy bodies and neuronal loss in the characteristic pattern of that found in PD can be demonstrated at post-mortem examination in subjects with no clinical evidence of PD during life.
