9 Fundamental Differences Between Parkinson’s Disease and Essential Tremor

differences between Parkinson's Disease and Essential Tremor

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Similarities and Differences Between Parkinson’s Disease and Essential Tremor 

Parkinson’s disease (PD) and essential tremor (ET) fall under the movement disorders category, yet essential tremor is approximately eight times more prevalent than Parkinson’s disease. While these disorders share certain similarities, they also exhibit several notable distinctions. Additionally, they differ in medical coding, where they are assigned different ICD-10-CM codes

Similarities Shared by PD and ET

One of the main symptoms of both PD and ET is tremors, an involuntary and rhythmic shaking. This similarity can cause a healthcare professional to diagnose one of these disorders for the other mistakenly. Therefore, the physician must understand the characteristics of each to identify the correct diagnosis and treatment.

Differences Between PD and ET  

According to ParkinsonsDisease.net, the nine fundamental differences between Parkinson’s disease and essential tremor are listed in the table below.

differences between Parkinson's Disease and Essential Tremor

Making a Final Diagnosis Between PD and ET

Once a physician has narrowed the diagnosis down to Parkinson’s and essential tremor, they may perform a nuclear imaging procedure called DaTscan to identify the specific disorder. According to Providence.org, this test offers physicians the ability to observe dopamine levels within the brain and assess the potential degeneration of neurons.

This diagnostic technique involves the fusion of medication with imaging technology known as single photon emission computed tomography (SPECT). In the case of individuals with Parkinson’s, a noticeable depletion of dopamine occurs. Conversely, patients afflicted with essential tremor do not exhibit a decline in dopamine production.

Name That Code Coding Exercise on DaTscan imaging test CPT and HCPCS

ICD-10-CM Coding

The ICD-10-CM codes for Parkinson’s disease and essential tremor are located in Chapter 6: Diseases of the nervous system, code range G00-G99/Extrapyramidal and movement disorders (G20-G26).

Parkinson’s Disease (PD)

PD currently has one ICD-10-CM code. However, that will change on October 1, 2023, when code G20 becomes category G20 and five new codes are added.

For now, though, coders must still use G20. To find Parkinson’s disease in the Alphabetic Index, go to

Disease, diseased – see also Syndrome; Disease, Parkinson’s G20

In the Tabular, G20 Parkinson’s disease applies to:

  • Hemiparkinsonism
  • Idiopathic Parkinsonism or Parkinson’s disease
  • Paralysis agitans
  • Parkinsonism or Parkinson’s disease NOS
  • Primary Parkinsonism or Parkinson’s disease

There are notations, inclusions, and exclusions that you need to review before selecting the specific code. These notes are critical to accurate coding.

For example, there is an Excludes1 note at G20 that indicates if the patient has dementia with Parkinsonism, G20 may not be assigned. Instead, G31.83 should be reported.

An Excludes2 note is listed for all codes in the G00-G99 range that indicate if the patient has PD and also has any of the following conditions, both conditions should be reported:

  • 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)

Essential Tremor (ET)

ET is listed under G25 Other extrapyramidal and movement disorders.

To find essential tremor in the Alphabetic Index, go to:

Tremor(s); essential (benign) G25.0

In the Tabular, G25.0 Essential tremor is applicable to:

  • Familial tremor

There is an Excludes1 note that indicates tremor NOS should be reported with R25.1 and not G25.0. Therefore, if the type of tremor is unspecified, R25.1 should be assigned rather than G25.0.

An Excludes2 note is listed to indicate if the patient has a sleep-related movement disorder, G47.6- should be reported in addition to G25.0 for essential tremor.

Also, be sure and look at the additional Excludes2 note at the beginning of the G00-G99 code range (as listed above) in case any additional conditions from that list need to be reported.


Parkinson’s disease and essential tremor are movement disorders that share certain symptoms, mainly tremors. They have many differences, however, and their treatment is completely different. A physician must make an accurate diagnosis to provide the right treatment. A DaTscan imaging test may be performed to assist in this diagnosis. Hopefully, as a medical coder, this post has given you the knowledge you need to accurately locate and verify the correct diagnosis codes for these two disorders.

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  1. Thanks for pointing out that more than half the cases of essential tremor have a family history of the disease. My husband’s father has been struggling with tremors for the past couple of years, and we are trying to learn more about it and find ways to help him since there is a chance it will happen to my husband too. We’ll have to look into gloves and other things that could help steady his hand so that he can start doing everyday things that he struggles with now, and so that we can know what works if my husband also starts to experience it.

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