Differential diagnosis of parkinsonian syndromes

The differential diagnosis of Parkinson's syndrome is of considerable therapeutic relevance: while idiopathic Parkinson's disease responds well to dopaminergic drugs, other Parkinson syndromes generally are not or only slightly sensitive to Dopa, and side effects must be expected in early stages and even at low doses of medication, Idiopathic Parkinson's disease must be distinguished from: I) the symptomatic forms (especially drug-induced), 2) pseudoparkinsonism (in cases of cerebral microangiopathy, malresorption hydrocephalus, etc.), and 3) the large group of Parkinson plus syndromes (complex neurodegenerative diseases) with the two most common entities multisystem atrophy (MSA) and progressive supranuclear palsy (PSP; Steele-Richardson-Olszewski syndrome) and the more (are forms of corticobasal degeneration (CBD) and diffuse Lewy bodies disease (DLB). An important but previously underestimated factor in the differential diagnosis is the Parkinson-dementia-complex. Besides overlap of Parkinson's and Alzheimer's diseases, diffuse Lowy body disease (DLB), which is not sufficiently known by many physicians, must also be taken into account. This disease can be readily identified by its fluctuating course, impairments of vigilance, early hallucinations, as well as its paradoxical responses to antipsychotic drugs. The early diagnosis of Parkinson's disease and its secure differential diagnostic delineation is a challenging and fascinating task for physicians: it opens up the way to treat the patients with successful therapeutic strategies and to a firm evaluation of the prognosis.