November 16, 2015

Lewy Body Dementia and ICD-10

By Kim Carr, RHIT, CCS, CDIP, CCDS, AHIMA-Approved ICD-10-CM/PCS Trainer

Lewy body dementia is the second-most common type of progressive dementia after Alzheimer’s disease, and it is captured with ICD-10-CM code G31.83, Dementia with Lewy Bodies. G31.83 is listed in section G31, titled "Other degenerative diseases of nervous system, not elsewhere classified,” and is included in category G31.8, titled "Other specified degenerative diseases of nervous system."

It’s important to note that Section G31 has Type 2 exclusions. Type 2 exclusions indicate that the conditions excluded are not part of the condition represented by the code, but the patient may have both conditions at the same time. Coders need to be sure to review section G31's exclusions before assigning this code for reimbursement purposes.

Section G31 also contains an instructional note reading “use additional code to identify” dementia with behavioral disturbance, a CC captured with code F02.81, or dementia without behavioral disturbance, which is captured with code F02.80. According to Coding Conventions, G31.83 must be followed by one of these two code(s) that represent the manifestation.

In addition to Lewy body dementia, the code G31.83 also identifies the following: 

  • Dementia with Parkinsonism and Lewy body disease. As far as the MS-DRG assignment, under version 33.0, code G31.83 groups to a two-tiered MS-DRG
  • MS-DRG 056: Degenerative nervous system disorders with MCC, or
  • MS-DRG 057: Degenerative nervous system disorders without MCC

Some documented descriptive synonyms of Lewy body dementia can include:

  • Dementia due to Parkinson's disease – but keep in mind, the physician must link the dementia to the Parkinson’s disease. 

Other documented descriptive synonyms for Lewy body dementia are:

  • Diffuse Lewy body disease
  • Lewy body dementia with or without behavioral disturbance
  • Senile dementia of the Lewy body type

Lewy body dementia can also be abbreviated as LBD if this is an approved abbreviation for your facility, otherwise the physician must clarify this abbreviation.

Documentation of dementia as a chronic, preexisting condition can be vague and disconnected from other diagnosed diseases or disorders, making it difficult for the coder to select the most accurate or specific code.

As always, when medical record documentation is not clear or the documentation does not link the dementia to an underlying disease or disorder, coders or CDI specialists need to query the physician for clarification to identify the type of dementia and the underlying cause. 

Coding and sequencing for Lewy body dementia is dependent on the physician’s documentation in the medical record and application of ICD-10-CM Official Coding Guidelines and Conventions. G31.83 is not a CC or MCC, but the presence of the disease can increase nursing care and/or the patient’s length of stay, and therefore it is very important to capture it as a secondary diagnosis to substantiate the resources the patient consumed. 

About the Author 

Kim Carr, RHIT, CCS, CDIP, CCDS, AHIMA-Approved ICD-10-CM/PCS Trainer, is the director of clinical documentation at HRS. She has nearly 30 years of experience and a strong background in revenue cycle improvement, coding and compliance, coding education, and denials management, which informs her auditing and clinical documentation improvement work. 

Contact the Author


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