Vascular parkinsonism: an update.

Vascular parkinsonism (VP), resulting from cerebrovascular disease, is a rare disorder with a characteristic motor and non-motor clinical profile distinct from sporadic/idiopathic Parkinson disease (PD) and other parkinsonian disorders. It accounts for 3-6% of all parkinsonian syndromes and may overlap with other parkinsonisms. Clinical features of VP are heterogenous and include bilateral rigidity with lower body predominance, bradykinesia, postural instability, shuffling gait, falls, corticospinal symptoms and cognitive impairment, tremor being rare or absent. An international working group recommended three VP subtypes: (1) the acute or subacute poststroke type: asymmetric parkinsonism due to involvement of the nigrostriatal system and response to dopaminergic drugs, (2) the more frequent insidious onset subtype due to ischemic deep white matter lesions and/or lacunar infarcts presents with progressive, symmetrical parkinsonism, prominent postural instability, gait impairment, corticospinal, pseudobulbar, urinary and cognitive symptoms, and poor levodopa response; (3) mixed VP/PD and other neurodegenerative parkinsonisms showing overlaps between these forms, with upper and lower body rigidity, resting tremor, dementia and positive levodopa response. Neuroimaging shows brain atrophy, widespread deep white matter lesions, lacunar infarcts and rare direct damage to nigrostriatal areas. Advanced MRI techniques and dopamine transporter imaging may be useful in the differentiation of VP with PD and other neurodegenerative parkinsonian syndromes. Neuropathology of VP reveals multiple subcortical ischemic lesions due to small vessel disease in basal ganglia and deep white matter, less often lesions of striatum, and substantia nigra involving cortico-basal ganglia-cortical and other neuronal circuits. Lewy pathology is usually absent. New molecular biomarkers will help to differentiate VP from other parkinsonian syndromes. The response of VP to different therapeutic strategies is modest. Further studies are warranted to explore the role of vascular lesions in the pathogenesis of VP and to demonstrate the efficacy of new therapy options.