Basic of Parkinson’s disease ICD-10 CM coding

Parkinson’s disease (paralysis agitans) is an idiopathic neurological condition marked by degeneration and dysfunction within the basal ganglia, clusters of nerve cells (neurons) at the base of the cerebrum located on both sides of the thalamus, above the brainstem. The basal ganglia may also be referred to as separate structures that include the caudate nucleus, putamen, and globus pallidus.

ICD-10 code G20 for Parkinson’s disease is a medical classification as listed by WHO under the range – Diseases of the nervous system .

G20 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.

This disease involves the degeneration of the nigral neurons, a group of specialized cells in the midbrain that contain neuromelanin and manufacture the neurotransmitter dopamine. When 75 to 80 percent of the dopamine innervation is destroyed, signs and symptoms of parkinsonism begin to manifest. These symptoms include tremor, rigidity, shuffling gait, drooling, “pill rolling” hand movement, and impaired control of facial muscles.

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Parkinson’s disease ICD-10 CM coding

Currently, there is only one ICD-10-CM code for PD (G20) located in Chapter 6, Diseases of the Nervous System (G00-G99). Code G20 is nonspecific and does not capture motor fluctuations and dyskinesia that emerge as PD advances.

From October 1, 2023 code G20 will become category G20.- (Parkinson’s disease). It will expand into three new subcategories and five new codes. According to the CMS, coders can expect to see the following under category G20.- in the upcoming 2024 ICD-10-CM Tabular List:

G20.-, Parkinson’s disease
               Hemiparkinsonism
               Idiopathic Parkinsonism or Parkinson’s disease
               Paralysis agitans
               Primary Parkinsonism or Parkinson’s disease

G20.A-, Parkinson’s disease without dyskinesia
                              G20.A1, Parkinson’s disease without dyskinesia, without mention of fluctuations
                                             Parkinson’s disease NOS
                                             Parkinson’s disease without dyskinesia, without mention of OFF episodes
                              G20.A2, Parkinson’s disease without dyskinesia, with fluctuations
                                             Parkinson’s disease without dyskinesia, with OFF episodes

G20.B-, Parkinson’s disease with dyskinesia
                              Excludes1: drug-induced dystonia (G24.0-)
                              G20.B1, Parkinson’s disease with dyskinesia, without mention of Fluctuations
                                             Parkinson’s disease with dyskinesia, without mention of OFF episodes
                              G20.B2, Parkinson’s disease with dyskinesia, with fluctuations
                                             Parkinson’s disease with dyskinesia, with OFF episodes

G20.C, Parkinsonism, unspecified
                              Parkinsonism, NOS
                              Excludes1: Parkinson’s disease NOS (G20.A1)
                                                            Parkinson’s disease with dyskinesia (G20.B-)
                                                            Parkinson’s disease without dyskinesia (G20.A-)
                                                            Secondary parkinsonism (G21-)

Note: The inclusion term, Parkinsonism or Parkinson’s disease NOS, is no longer listed under Category G20.-. 

Beginning October 1, codes in category G20.- will have a note to “use additional code, if applicable,” to identify:

Dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)
Dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)
Dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)
Dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)
Dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)
Mild neurocognitive disorder due to known physiological condition (F06.7-)

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2024 ICD 10 coding guidelines update for Parkinson’s code

Prior to making their last code determination, coders ought to make certain to survey the coding rules and shows. For instance the “code first,” “use additional code,” and “in diseases classified elsewhere” notes of the “etiology/manifestation convention” in the 2024 ICD-10-CM Official Guidelines for Coding and Reporting indicate a coding convention.

This instruct coders to report the basic condition first, trailed by the sign, for conditions that have both a fundamental etiology and various body framework indications because of the hidden etiology. Informative notes of “use additional code” and “code first” show the appropriate sequencing of codes.

The rules additionally demonstrate that “… An illustration of the etiology/indication show is dementia with Parkinson’s sickness. A code from category G20 appears first in the Alphabetic Index, followed by codes F02.80 or F02.81- enclosed in brackets.

Codes F02.80 and F02.81- represent the manifestations of dementia in diseases classified elsewhere, with or without behavioral disturbance, whereas a code from category G20.- represents the underlying etiology, Parkinson’s disease, and must be sequenced first.