Parkinsonism is a clinical syndrome characterized by tremor, bradykinesia, rigidity, and postural instability. These are the four motor symptoms found in Parkinson's disease (PD), after which it is named, dementia with Lewy bodies (DLB), Parkinson's disease dementia (PDD), and many other conditions. A wide range of causes may lead to this set of symptoms, including neurodegenerative conditions, drugs, toxins, metabolic diseases, and neurological conditions other than PD.
About 7% of people with parkinsonism developed symptoms as a result of side effects of medications, mainly neuroleptic antipsychotics especially the phenothiazines (such as perphenazine and chlorpromazine), thioxanthenes (such as flupenthixol and zuclopenthixol) and butyrophenones (such as haloperidol), and rarely, antidepressants. The incidence of drug-induced parkinsonism increases with age. Drug-induced parkinsonism tends to remain at its presenting level and does not worsen like Parkinson's disease.
Evidence exists of 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. Manganese may accumulate in the basal ganglia, leading to the abnormal movements. 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.
Parkinsonism occurs in many conditions.
- Neurodegenerative conditions and Parkinson plus syndrome
- Corticobasal degeneration
- Dementia with Lewy bodies
- Frontotemporal dementia (Pick's disease)
- Gerstmann–Sträussler–Scheinker syndrome
- Huntington's disease
- Lytico-bodig disease (ALS complex of Guam)
- Multiple system atrophy (Shy–Drager syndrome)
- Neuronal ceroid lipofuscinosis
- Olivopontocerebellar atrophy
- Pantothenate kinase-associated neurodegeneration, also known as neurodegeneration with brain iron accumulation
- Parkin mutation (hereditary juvenile dystonia)
- Parkinson's disease
- Parkinson's disease dementia
- Progressive supranuclear palsy
- Wilson's disease
- X-linked dystonia parkinsonism (Lubag syndrome)
- Drug-induced ("pseudoparkinsonism")
- MDMA addiction and frequent use
- Creutzfeldt–Jakob disease
- Encephalitis lethargica
- HIV infection and AIDS
- Carbon monoxide
- Carbon disulfide
- Toluene (inhalant abuse: "huffing")
- Chronic traumatic encephalopathy (boxer's dementia or pugilistic encephalopathy)
- Binswanger's disease (subcortical leukoencephalopathy)
- Vascular dementia (multi-infarct)
- Damage to the brain stem (especially dopaminergic nuclei of the substantia nigra), basal ganglia (especially globus pallidus) and the thalamus.
- Orthostatic tremor
- Paraneoplastic syndrome: neurological symptoms caused by antibodies associated with cancers
- Rapid onset dystonia parkinsonism
- Autosomal recessive juvenile parkinsonism
A 2018 review article said that the relationship (if any) between Parkinson's disease and essential tremor is not clear.