Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia (slowed movements), rigidity, and postural instability.

Both hypokinetic features (bradykinesia and akinesia) and hyperkinetic features (cogwheel rigidity and tremors at rest) are displayed in parkinsonism.

Signs and symptoms

Parkinsonism is a clinical syndrome characterized by the four motor signs that are found in Parkinson's disease: tremor, bradykinesia (slowed movements), rigidity, and postural instability.

  • Difficulty sleeping
  • Dry skin
  • Apathy
  • Lack of facial expressions
  • Balance problems
  • Frequent falls
  • Very small handwriting
  • Rigid, stiff muscles
  • Cogwheeling (jerky feeling in arm or leg)
  • Upgaze impairment
  • Plastic, dead feeling resistance known as "lead-pipe rigidity".

Conditions

Parkinsonism occurs in many conditions.

Neurological

Neurodegenerative conditions and Parkinson-plus syndromes that can cause parkinsonism include:

  • Corticobasal degeneration
  • Frontotemporal dementia (Pick's disease)
  • Gerstmann–Sträussler–Scheinker syndrome
  • Progressive supranuclear palsy
  • Encephalitis lethargica
  • Japanese encephalitis

Toxins

Evidence exists to show a link between exposure to pesticides and herbicides and PD; a two-fold increase in risk was seen with paraquat or maneb/mancozeb exposure.

Chronic manganese (Mn) exposure has been shown to produce a parkinsonism-like illness characterized by movement abnormalities. This condition is not responsive to typical therapies used in the treatment of PD, suggesting an alternative pathway than the typical dopaminergic loss within the substantia nigra. A mutation of the SLC30A10 gene, a manganese efflux transporter necessary for decreasing intracellular Mn, has been linked with the development of this parkinsonism-like disease. The Lewy bodies typical to PD are not seen in Mn-induced parkinsonism.

Other toxins that have been associated with parkinsonism are:

  • Annonaceae
  • Carbon monoxide
  • Mercury
  • Rotenone
  • Toluene (inhalant abuse: "huffing")

Vascular

Vascular Parkinsonism is typically caused by mini strokes. It typically affects gait, often marked with rigidity. Multiple conditions related to Vascular Parkinsonism include:

  • Binswanger's disease (subcortical leukoencephalopathy)
  • Dural arteriovenous malformation / dAVM (reversible through dAVM treatment)

Other

  • Chronic traumatic encephalopathy (boxer's dementia or pugilistic encephalopathy) basal ganglia (especially globus pallidus) and the thalamus.
  • Hypothyroidism
  • Paraneoplastic syndrome: neurological symptoms caused by antibodies associated with cancers
  • Rapid onset dystonia parkinsonism
  • Autosomal recessive juvenile parkinsonism

Differential diagnosis

Secondary parkinsonism, including vascular parkinsonism and drug-induced parkinsonism.

Drug-induced parkinsonism

About 7% of people with parkinsonism developed symptoms as a result of side effects of medication, mainly neuroleptic antipsychotics, especially the phenothiazines (such as perphenazine and chlorpromazine), thioxanthenes (such as flupentixol and zuclopenthixol) and butyrophenones (such as haloperidol); and rarely, antidepressants. Yet another drug that can induce parkinsonism is the antihistaminic medication cinnarizine, usually prescribed for motion sickness; this is because besides antagonizing histamine receptors this drug antagonizes the dopamine D2 receptors.

Implicated medications include:

  • Antipsychotics
  • MDMA (addiction and frequent use)
  • Tetrabenazine

Society and culture

In the United States, the 2021 National Defense Authorization Act (NDAA) added parkinsonism to the list of presumptive conditions associated with Agent Orange exposure, enabling affected service members to receive Veterans Affairs disability benefits.

References

  • GeneReviews/NIH/NCBI/UW entry on Perry syndrome
  • GeneReviews/NCBI/NIH/UW entry on X-Linked Dystonia-Parkinsonism