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Table 183-2

Features Suggesting an Atypical or Secondary Cause of Parkinsonism

Symptoms/SignsAlternative Diagnosis to Consider
History
Early speech and gait impairment (Lack of tremor, lack of motor asymmetry)Atypical parkinsonism
Exposure to neurolepticsDrug-induced parkinsonism
Onset prior to age 40Genetic form of PD
Liver diseaseWilson's disease, non-Wilsonian hepatolenticular degeneration
Early hallucinations and dementia with later development of PD featuresDementia with Lewy bodies
Diplopia, impaired down gazePSP
Poor or no response to an adequate trial of levodopaAtypical or secondary parkinsonism
Physical Examination
Dementia as first or early featureDementia with Lewy bodies
Prominent orthostatic hypotensionMSA-p
Prominent cerebellar signsMSA-c
Slow saccades with impaired down gazePSP
High-frequency (6-10 Hz) symmetric postural tremor with a prominent kinetic componentEssential tremor

Abbreviations: MSA-c, multiple-system atrophy-cerebellar type; MSA-p, multiple-system atrophy-Parkinson's type; PD, Parkinson's disease; PSP, progressive supranuclear palsy.