8A00
Parkinsonism
Description
Parkinsonism is a clinical syndrome characterised by four cardinal features: rest tremor, muscular rigidity, akinesia or bradykinesia, and postural disturbances which include shuffling gait and flexed posture and loss of postural reflexes. Bradykinesia and one other clinical feature is required to make a diagnosis of Parkinsonism. Parkinsonism may result from a variety of conditions including progressive neurodegenerative disorders such as Parkinson Disease or Atypical Parkinsonism where the progressive degeneration of nigral and other neurons leads to dopamine deficiency. Parkinsonism may also be a result of structural lesions such as strokes or tumours or blockage of dopamine receptors in the striatum by drugs such as neuroleptics. [1]
Diagnostic requirements
WHO clinical descriptions and diagnostic requirements [1,2].
Tremor, rigidity, akinesia, postural disturbances, exclusion of other diseases that can cause parkinsonism
Subcategories
8A00.0 Parkinson disease
Parkinson Disease is a gradual onset progressive degenerative disease whose cardinal manifestations include bradykinesia plus one of the following-tremor, rigidity or postural instability. Nonmotor manifestations include autonomic dysfunction and neuropsychiatric features. [1]
8A00.1 Atypical parkinsonism
Atypical parkinsonism is a term used to describe several neurodegenerative conditions where the degeneration extends beyond the substantia nigra and is more extensive than seen in conditions like Parkinson disease. The clinical picture is often more complex than PD and patients may have apraxia, supranuclear ophthalmoplegia or autonomic failure. [1]
8A00.2 Secondary parkinsonism
Secondary parkinsonism is a term used to describe Parkinsonism due to a known agent such as drugs, infections, toxins or structural lesions. [1]
8A00.3 Functional parkinsonism
Functional movement disorder with mixed features of functional tremor but also slowness and stiffness which can be demonstrated to be variable and internally inconsistent. No cause has been identified after investigation. [1]
Coded elsewhere
References
- World Health Organization. International Classification of Diseases, 11th Revision, for Mortality and Morbidity Statistics (ICD-11 MMS), 2026-01 release. World Health Organization; 2026.
- World Health Organization. Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural or Neurodevelopmental Disorders (CDDR). World Health Organization; 2024.
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