Distinguishing Vascular Parkinsonism from Idiopathic Parkinson's Disease

Pathophysiological Differences

Idiopathic Parkinson's disease is a synucleinopathy characterized by abnormal cytoplasmic accumulation of alpha-synuclein in neurons, forming Lewy bodies in the substantia nigra and other brain regions, with symptoms manifesting after approximately 40-50% of dopaminergic neurons in the substantia nigra have been lost, according to the American Academy of Neurology 1, 2, 3

The American Academy of Neurology recommends recognizing asymmetric onset with unilateral symptoms initially as a characteristic of idiopathic Parkinson's disease 2
Resting tremor is a prominent cardinal feature of idiopathic Parkinson's disease, as stated by the American Academy of Neurology 2, 3
Bradykinesia plus rigidity or tremor are also characteristic of idiopathic Parkinson's disease, according to the American Academy of Neurology 2
Peak onset of idiopathic Parkinson's disease occurs between 60-70 years, as reported by the American Academy of Neurology 3

The American College of Radiology states that decreased striatal uptake, typically beginning in putamen and progressing to caudate, is characteristic of idiopathic Parkinson's disease on Dopamine Transporter Imaging (I-123 ioflupane SPECT/CT) 2
A normal DaTscan essentially excludes parkinsonian syndromes, including idiopathic Parkinson's disease, as stated by the American College of Radiology 2
The American College of Radiology reports that multiple focal cortical and subcortical metabolic defects are characteristic of vascular dementia/parkinsonism on FDG-PET/CT 4
The pattern of metabolic defects in vascular dementia/parkinsonism differs from the posterior cortical hypometabolism typical of Alzheimer's disease, as stated by the American College of Radiology 5

The American College of Radiology recommends obtaining MRI brain without contrast to look for white matter lesions, lacunar infarcts, and vascular changes when evaluating a patient with parkinsonism 4, 5
The American Academy of Neurology suggests considering DaTscan if diagnosis remains unclear, as a normal scan excludes idiopathic PD and supports vascular parkinsonism 2

The American College of Radiology advises recognizing that mixed pathology occurs in up to 38% of cases, particularly in elderly patients, and to consider vascular parkinsonism rather than assuming dementia with Lewy bodies 5
The American College of Cardiology recommends recognizing cardiovascular risk factors (hypertension, diabetes, smoking, atrial fibrillation) that predispose to vascular parkinsonism, as stated by the American College of Radiology 5