This post was originally published on April 16, 2019, and updated on January 29, 2020. In this post, we discuss nine fundamental differences between Parkinson’s disease and essential tremor. Once you know these differences, you will better understand how to report them in ICD-10. 

Parkinson’s disease (PD) and essential tremor (ET) are both movement disorders, with essential tremor being about eight times more common than Parkinson’s disease. Although they are similar disorders, there are many differences between Parkinson’s disease and essential tremor. 

man with tremors due to having Parkinson's disease and essential tremor

How Parkinson’s Disease and Essential Tremor Are Similar

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 mistakenly diagnose one of these disorders for the other. Therefore, it is critical that the physician understands the characteristics of each of the disorders in order to make the correct diagnosis and treatment.

Differences Between PD and ET

According to, the nine fundamental differences between Parkinson’s disease and essential tremor are listed as follows:chart describing the 9 differences between Parkinson's and Essential Tremor

Once a physician has narrowed the diagnosis down to Parkinson’s and essential tremor, he or she may choose to perform a DaTscan in order to identify the specific disorder.

ICD-10 Coding for PD and ET

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

How To Locate and Verify Parkinson’s disease

To find Parkinson’s disease in the Alphabetic Index, a medical coder can go to:

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

In the Tabular, G20 Parkinson’s disease is applicable 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 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)

How to Locate and Verify Essential Tremor

To find essential tremor in the Alphabetic Index, the coder can 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 with the main one being tremors. They have many differences, however, and their treatment is completely different. A physician must make an accurate diagnosis, so the right treatment can be provided. A DaTscan 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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