ICD-10-CM Code G21

Secondary parkinsonism

Version 2021 Non-Billable Code

Not Valid for Submission

G21 is a "header" nonspecific and non-billable code code, consider using a code with a higher level of specificity for a diagnosis of secondary parkinsonism. The code is NOT valid for the year 2021 for the submission of HIPAA-covered transactions.

ICD-10:G21
Short Description:Secondary parkinsonism
Long Description:Secondary parkinsonism

Consider the following ICD-10 codes with a higher level of specificity:

  • 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 - ... unspecified

Tabular List of Diseases and Injuries

The Tabular List of Diseases and Injuries is a list of ICD-10 codes, organized "head to toe" into chapters and sections with guidance for inclusions, exclusions, descriptions and more. The following references are applicable to the code G21:

Type 1 Excludes

Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
  • dementia with Parkinsonism G31.83
  • Huntington's disease G10
  • Shy-Drager syndrome G90.3
  • syphilitic Parkinsonism A52.19

Clinical Information

  • PARKINSON DISEASE SECONDARY-. conditions which feature clinical manifestations resembling primary parkinson disease that are caused by a known or suspected condition. examples include parkinsonism caused by vascular injury drugs trauma toxin exposure neoplasms infections and degenerative or hereditary conditions. clinical features may include bradykinesia rigidity parkinsonian gait and masked facies. in general tremor is less prominent in secondary parkinsonism than in the primary form. from joynt clinical neurology 1998 ch38 pp39 42

Code Classification

  • Diseases of the nervous system (G00–G99)
    • Extrapyramidal and movement disorders (G20-G26)
      • Secondary parkinsonism (G21)

Code History

  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016
    (First year ICD-10-CM implemented into the HIPAA code set)
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021

Information for Patients


Parkinson's Disease

Also called: Paralysis agitans, Shaking palsy

Parkinson's disease (PD) is a type of movement disorder. It happens when nerve cells in the brain don't produce enough of a brain chemical called dopamine. Sometimes it is genetic, but most cases do not seem to run in families. Exposure to chemicals in the environment might play a role.

Symptoms begin gradually, often on one side of the body. Later they affect both sides. They include

  • Trembling of hands, arms, legs, jaw and face
  • Stiffness of the arms, legs and trunk
  • Slowness of movement
  • Poor balance and coordination

As symptoms get worse, people with the disease may have trouble walking, talking, or doing simple tasks. They may also have problems such as depression, sleep problems, or trouble chewing, swallowing, or speaking.

There is no lab test for PD, so it can be difficult to diagnose. Doctors use a medical history and a neurological examination to diagnose it.

PD usually begins around age 60, but it can start earlier. It is more common in men than in women. There is no cure for PD. A variety of medicines sometimes help symptoms dramatically. Surgery and deep brain stimulation (DBS) can help severe cases. With DBS, electrodes are surgically implanted in the brain. They send electrical pulses to stimulate the parts of the brain that control movement.

NIH: National Institute of Neurological Disorders and Stroke

  • Deep brain stimulation (Medical Encyclopedia)
  • Parkinson disease (Medical Encyclopedia)
  • Secondary parkinsonism (Medical Encyclopedia)
  • Swallowing problems (Medical Encyclopedia)

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