Differential diagnosis of parkinsonism

The diagnosis of Parkinson's disease is predominantly clinical, based on a combination of the cardinal features of tremor, bradykinesia and rigidity. The differential essentially lies between other conditions resulting in tre mor, of which essential tremor is the commonest, and other akinetic-rigid s yndromes. These include progressive supranuclear palsy, multiple system atr ophy, toxins and other degenerative disorders, including diffuse Lewy body disease and corticobasal degeneration. The key clinical features of these d isorders and a practical diagnostic approach are briefly reviewed in this a rticle.