Parkinsonism
Parkinsonism is the clinical syndrome of bradykinesia plus rest tremor, rigidity, or postural instability, produced by idiopathic Parkinson disease or by secondary/atypical causes (drug-induced, vascular, Parkinson-plus syndromes, normal pressure hydrocephalus). Management treats the identified cause: stop the offending drug, shunt confirmed normal pressure hydrocephalus, or start levodopa for idiopathic disease.
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What this article covers
- Overview
Definition: the clinical syndrome of bradykinesia plus at least one of rest tremor, rigidity, or postural/gait instability; a shared final motor phenotype produced by several distinct diseases, not a single diagnosis.
- Epidemiology
Idiopathic Parkinson disease accounts for the largest share of parkinsonism and rises sharply in incidence after age 60.
- Risk factors
Age: the dominant risk factor for idiopathic disease and a contributor to vascular parkinsonism and normal pressure hydrocephalus.
- Pathophysiology
Idiopathic Parkinson disease: loss of substantia nigra pars compacta dopaminergic neurons with alpha-synuclein Lewy body pathology, reducing dopaminergic input to the striatum (see parkinson-disease for detail).
- Clinical features
Core syndrome (shared across causes): bradykinesia plus at least one of rest tremor, cogwheel rigidity, or postural/gait instability; shared additional features include freezing gait, stooped…
- Differential diagnosis
Idiopathic Parkinson disease: asymmetric onset persisting throughout the course, robust sustained levodopa response, and prominent nonmotor premotor symptoms; the diagnosis reached once secondary causes are excluded.
- Diagnosis
Basis of diagnosis: clinical recognition of the core syndrome (bradykinesia plus tremor, rigidity, or postural instability), followed by a structured search for red flags pointing away from…
- Management
First step, identify and treat the underlying cause: the defining management step for parkinsonism, unlike idiopathic disease where dopaminergic therapy starts immediately; drug-induced parkinsonism…
- Complications
Falls and fracture: prominent and early in progressive supranuclear palsy, multiple system atrophy, and normal pressure hydrocephalus, given the gait-predominant nature of these syndromes.
- Prognosis
Drug-induced parkinsonism: generally reversible over months after stopping the offending agent; persistence beyond 6 months usually reflects unmasked idiopathic disease.
- Prevention
Medication stewardship: avoid unnecessary or prolonged dopamine receptor-blocking antipsychotics and antiemetics, using the lowest effective dose when required, to prevent drug-induced parkinsonism.
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Parkinson disease is a slowly progressive neurodegenerative disorder from loss of substantia nigra dopaminergic neurons with alpha-synuclein Lewy body pathology, presenting with asymmetric rest tremor, bradykinesia, rigidity, and gait impairment. Diagnosis is clinical; first-line treatment is levodopa-carbidopa or a dopamine agonist.
- Dementia with Lewy bodies
Dementia with Lewy bodies is a synuclein-related neurodegenerative dementia defined by dementia plus parkinsonism, fluctuating attention, visual hallucinations, and REM sleep behavior disorder arising within about two years of each other. Diagnosis is clinical; acetylcholinesterase inhibitors treat cognitive symptoms and first-generation antipsychotics must be avoided because of severe neuroleptic sensitivity.
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