Parkinson’s Disease and ICD-10-CM Coding

Gloryanne Bryant, RHIA, CDIP, CCS, CCDS Inpatient Coding Leave a Comment

Parkinson’s Disease and ICD-10-CM Coding

Parkinson’s disease is a progressive, systemic and debilitating neurodegenerative condition of the brain with a wide range of associated manifestations. Coding and Clinical Documentation Integrity (CDI) professionals should be reading over the health record documentation carefully. Capturing the specific manifestations in the clinical documentation then in turn in the ICD-10-CM codes can reveal the true patient picture and help with treatment decisions and medical research.

Back in 1817, Dr James Parkinson wrote about a “shaking disease”, later named Parkinson’s Disease or PD. Parkinson’s Disease is a neurodegenerative disease of the brain, which impacts an individual’s motor function. Parkinson’s Disease is a very common neurological disorder, affecting approximately one million people in the United States. It is estimated that approximately 60,000 Americans are diagnosed with PD each year, and this number does not reflect the thousands of cases that go undetected, and the alarming thing is the prevalence of PD cases is increasing. According to the American Parkinson’s Disease Association (APDA), someone is diagnosed every 9 minutes with PD. Men are more likely to get Parkinson than women. Worldwide, up to 14 million people have a diagnosis of PD.

Most individuals with PD are diagnosed when they are around 50 years old or older, but early-onset PD also occurs, as we’ve seen with actor Michael J. Fox and deceased professional boxer Muhammad Ali, this early-onset accounts for 10% of PD cases. I’m sure you know of someone with this disease and have seen the deterioration that occurs. For Coding and CDI professionals this condition is often a secondary diagnosis to an inpatient hospitalization.

Parkinson’s patients can have several associated non-motor symptoms, manifestations or issues. These include Neuropsychiatric, Autonomic and Sensory (per the APDA).


  • Depression
  • Anxiety
  • Sleep disorders                                                                   
  • Cognitive impairment and dementia                                      


  • Orthostatic hypotension
  • Constipation
  • Urinary dysfunction  
  • Sexual dysfunction                              


  • Visual disturbances
  • Loss of smell
  • Pain

In addition to the above manifestations, patients with PD can also have mood, behavioral and psychotic disturbances occur. Parkinson disease patients can suffer hallucinations, which are more common than you would think. These hallucinations can be of people, bugs, animals, non-threatening events, but still very disturbing. In addition, the muscles in the throat can get weak and make it difficult to swallow, so aspiration can occur. Along with this muscle weakness, the patient's gait will be unstable (difficulty maintaining balance) and “falls” can occur resulting in contusions and even fractures.

Treatment for PD includes medication, procedures (i.e., deep brain stimulation), therapy (Physical and Occupational Therapy), self-care (including exercise, using a walker), and nutrition. As manifestations increase in severity, the PD patient may be unable to eat or drink due to the swallowing weakness resulting in recurrent aspiration necessitating a PEG (Percutaneous Endoscopic Gastrostomy) placement or “Palliative Care,” so keep an eye out for this to be stated in the documentation and thus be coded.

I recently read in Medscape some information about a possible new treatment for Parkinson’s. Using GLP-1 medication, which are the glucagon-like peptide 1 drugs, the agonists (agonists liraglutide) of those receptors. The study reported that there was improvement in the clinical features of Parkinson's disease, including nonmotor symptoms and activities of daily living.

In ICD-10-CM Parkinson’s disease code is found in Chapter 6, Diseases of the Nervous System (code range G00-G99). ICD-10-CM code G20 presents Parkinson’s Disease. The ICD-10-CM tabular changes for FY2023 shows the following revisions to inclusions that were added to G20 which relate to some of the Chapter 5 additional codes for 2023.

G20 Parkinson's disease

Use Additional

Revise from   code to identify: Revise to code, if applicable, to identify:

Revise to   dementia with anxiety (F02.84, F02.A4, F02.B4, F02.C4)

Delete dementia without behavioral disturbance (F02.80)

Add dementia with behavioral disturbance (F02.81-, F02.A1-, F02.B1-, F02.C1-)

Add dementia with mood disturbance (F02.83, F02.A3, F02.B3, F02.C3)

Add dementia with psychotic disturbance (F02.82, F02.A2, F02.B2, F02.C2)

Add dementia without behavioral disturbance (F02.80, F02.A0, F02.B0, F02.C0)

Add mild neurocognitive disorder due to known physiological condition (F06.7-)

The full tabular for FY2023 contains additional guidance and instruction, so that should be reviewed carefully and completely.

American Hospital Association (AHA) Coding Clinic for ICD-10-CM has some advice that must be followed as well regarding “Systemic Diseases”. It tells us that, Systemic diseases (e.g., diabetes mellitus, hypertension, PD) are always coded, even in the absence of documented active intervention, since these types of conditions meet one or more of the elements of the definition given above. (AHA Coding Clinic, Second Quarter, 1990, page 14). Capturing all the associated complications of Parkinson’s is important for the true story of the patient and to keep up with ongoing research in this area.

For Coding and CDI professionals, the advice is to understand the specific disease process, watch the clinical documentation closely for information and indications of these associated manifestations of the disease so the ICD-10-CM code(s) can capture severity, acuity and risk of mortality.


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