2018 ICD-10-CM Diagnosis Code G21

Secondary parkinsonism

Type 1 Excludes
Type 1 Excludes Help
A type 1 excludes note is a pure excludes. It means "not coded here". A type 1 excludes note indicates that the code excluded should never be used at the same time as G21. A type 1 excludes note is for used for when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • dementia with Parkinsonism (
    ICD-10-CM Diagnosis Code G31.83

    Dementia with Lewy bodies

      2016 2017 2018 Billable/Specific Code
    Applicable To
    • Dementia with Parkinsonism
    • Lewy body dementia
    • Lewy body disease
    G31.83
    )
  • Huntington's disease (
    ICD-10-CM Diagnosis Code G10

    Huntington's disease

      2016 2017 2018 Billable/Specific Code
    Applicable To
    • Huntington's chorea
    • Huntington's dementia
    Code Also
    • dementia in other diseases classified elsewhere without behavioral disturbance (F02.80)
    G10
    )
  • Shy-Drager syndrome (
    ICD-10-CM Diagnosis Code G90.3

    Multi-system degeneration of the autonomic nervous system

      2016 2017 2018 Billable/Specific Code
    Applicable To
    • Neurogenic orthostatic hypotension [Shy-Drager]
    Type 1 Excludes
    • orthostatic hypotension NOS (I95.1)
    G90.3
    )
  • syphilitic Parkinsonism (
    ICD-10-CM Diagnosis Code A52.19

    Other symptomatic neurosyphilis

      2016 2017 2018 Billable/Specific Code
    Applicable To
    • Syphilitic parkinsonism
    A52.19
    )
The following code(s) above G21 contain annotation back-references
Annotation Back-References
In this context, annotation back-references refer to codes that contain:
  • Applicable To annotations, or
  • Code Also annotations, or
  • Code First annotations, or
  • Excludes1 annotations, or
  • Excludes2 annotations, or
  • Includes annotations, or
  • Note annotations, or
  • Use Additional annotations
that may be applicable to G21:
  • G00-G99
    2018 ICD-10-CM Range G00-G99

    Diseases of the nervous system

    Type 2 Excludes
    • certain conditions originating in the perinatal period (P04-P96)
    • certain infectious and parasitic diseases (A00-B99)
    • complications of pregnancy, childbirth and the puerperium (O00-O9A)
    • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
    • endocrine, nutritional and metabolic diseases (E00-E88)
    • injury, poisoning and certain other consequences of external causes (S00-T88)
    • neoplasms (C00-D49)
    • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
    Diseases of the nervous system
Clinical Information Code History
ICD-10-CM Codes Adjacent To G21
G12.29 Other motor neuron disease
G12.8 Other spinal muscular atrophies and related syndromes
G12.9 Spinal muscular atrophy, unspecified
G13 Systemic atrophies primarily affecting central nervous system in diseases classified elsewhere
G13.0 Paraneoplastic neuromyopathy and neuropathy
G13.1 Other systemic atrophy primarily affecting central nervous system in neoplastic disease
G13.2 Systemic atrophy primarily affecting the central nervous system in myxedema
G13.8 Systemic atrophy primarily affecting central nervous system in other diseases classified elsewhere
G14 Postpolio syndrome
G20 Parkinson's disease
G21 Secondary parkinsonism
G21.0 Malignant neuroleptic syndrome
G21.1 Other drug-induced secondary parkinsonism
G21.11 Neuroleptic induced parkinsonism
G21.19 Other drug induced secondary parkinsonism
G21.2 Secondary parkinsonism due to other external agents
G21.3 Postencephalitic parkinsonism
G21.4 Vascular parkinsonism
G21.8 Other secondary parkinsonism
G21.9 Secondary parkinsonism, unspecified
G23 Other degenerative diseases of basal ganglia

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.