9 Fundamental Differences Between Parkinson’s Disease and Essential Tremor

Differences Between Parkinson's Disease and Essential Tremor

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** This article was reviewed and updated on February 27, 2024. **

Examining the Similarities and Differences Between Parkinson’s Disease and Essential Tremor 

Exploring the slight differences in movement disorders, this article investigates the parallels and distinctions between Parkinson’s Disease (PD) and essential tremor (ET). While both conditions are categorized as movement disorders, essential tremor is approximately eight times more prevalent than Parkinson’s Disease. Beyond their shared classification, these disorders exhibit different characteristics, prompting a comprehensive examination of their clinical features and diagnostic distinctions. Moreover, their differentiation extends to medical coding, where distinct ICD-10-CM codes are used to report the individual diagnosis.

Similarities Shared by PD and ET

Parkinson’s Disease (PD) and essential tremor (ET) exhibit various symptoms, but a notable similarity lies in the presence of tremors, characterized by involuntary and rhythmic shaking. This symptom sometimes results in a misdiagnosis, highlighting the importance of medical professionals having a thorough understanding of each disorder’s distinct characteristics for accurate diagnosis and effective 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, a crucial step involves conducting a nuclear imaging procedure called DaTscan to identify the specific disorder. This diagnostic tool, as outlined by Providence.org, empowers physicians to observe dopamine levels within the brain and assess the potential degeneration of neurons.

DaTscan merges medication with imaging technology, notably single photon emission computed tomography (SPECT). Through this process, clinicians can identify distinct patterns in dopamine distribution within the brain. In Parkinson’s Disease, a noticeable depletion of dopamine occurs. Conversely, individuals afflicted with essential tremor typically showcase normal dopamine production, setting them apart from those with Parkinson’s Disease.

ICD-10-CM Coding

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

Parkinson’s Disease (PD)

Previously, PD had only one ICD-10-CM code: G20. However, that changed on October 1, 2023, when code G20 became category G20, and five new codes were added for FY 2024.

To find Parkinson’s Disease in the Alphabetic Index, go to Disease, diseased – see also Syndrome; Disease, Parkinson’s G20.A1. In the Tabular, we can verify this code as:

G20.A1, Parkinson’s disease without dyskinesia, without mention of fluctuations
Inclusion terms include:
Parkinson’s disease NOS
Parkinson’s disease without dyskinesia, without mention of OFF episodes

The four other new PD codes added for FY 2024 include:

G20.A2, Parkinson’s disease without dyskinesia, with fluctuations
G20.B1, Parkinson’s disease with dyskinesia, without mention of fluctuations
G20.B2, Parkinson’s disease with dyskinesia, with fluctuations
G20.C, Parkinsonism, unspecified

There are notations, inclusions, and exclusions that you need to review before selecting the specific code. For example, there is a “Use additional” note at G20 that instructs the coder to code, if applicable, to identity:

  • 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-)

In addition, an “Excludes2” note is listed for all codes in the G00-G99 range that indicates 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, we can verify this code as:

G25.0, Essential tremor
Familial tremor

An “Excludes1” note instructs the coder to assign R25.1 (Tremor, unspecified) instead of G25.0 when the type of tremor is not specified.

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, as listed above under the codes for Parkinson’s Disease, review the “Excludes2” note at the beginning of the G00-G99 code range in case any additional conditions from that list need to be reported.


Parkinson’s disease and essential tremor are movement disorders that share specific symptoms, mainly tremors. They have many differences, however, and their treatment is completely different. A physician must make an accurate diagnosis to provide proper 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.

Differences Between Parkinson's Disease and Essential Tremor
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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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