Other causes of parkinsonism.

This chapter deals with the 'other causes of parkinsonism with the exclusion of idiopathic Parkinson's disease, multiple system atrophy, progressive supranuclear palsy and corticobasal degeneration. It is a cursory glance over the endless list of 'secondary' causes of parkinsonism or parkinsonism due to acquired and inherited metabolic and neurodegenerative diseases. With the exception of drug-induced parkinsonism and 'vascular' parkinsonism, most such cases are rare. However, single rare causes must not be overlooked as there can be specific therapeutic consequences. Parkinsonism is often present amid a constellation of other symptoms. Careful evaluation of the personal, familial and environmental context, mode of onset and progression, clinical features, and drug response, together with imaging, biochemical and molecular tests, help in determining the underlying disease.