[Essential points to differentiate various diseases causing parkinsonism].

This review article deals with the cardinal features to differentiate various conditions which present with parkinsonism, other than Parkinson's disease, Lewy body disease, progressive supranuclear palsy and corticobasal degeneration. Special attention is paid to the distinctive clinical features, laboratory data and neuroimaging findings of frequent diseases as well as important ones including multiple system atrophies(MSA), drug-induced parkinsonism, vascular pseudo-parkinsonism and manganese intoxication due to parenteral nutrition. MRI is useful to diagnose MSA, vascular pseudo-parkinsonism and manganese intoxication. Benzamide derivatives including sulpiride, tiapride, metoclopramide and cisapride are the main causes of drug-induced parkinsonism in recent years in Japan.