Proper Documentation Essential for Dementia Coding in ICD-10

by | Published on Sep 2, 2019 | Medical Coding

Dementia Coding in ICD 10
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A progressive neurological disorder, dementia is a common and severe cause of disability among older people. Dementia is characterized by a group of symptoms associated with deterioration in memory or other thinking skills. As there are different types of dementia, diagnosing the condition can be challenging. Due to its debilitating effects, caring for a patient with dementia is also not easy. As they provide patients with individualized care, outsourcing medical billing and coding is a practical option for physicians to prepare and submit claims for accurate reimbursement.


Dementia is an umbrella term that covers several underlying major neurocognitive disorders. Behavioral disturbances, including psychotic symptoms, mood disturbance, agitation, apathy, aggression, combativeness, and “wandering off” may be present. Dementia not a part of natural aging.

According to, at least two of the following core mental abilities must be significantly affected to be considered dementia:

    • Memory
    • Communication and language
    • Ability to focus and pay attention
    • Reasoning and judgment
    • Visual perception

To diagnose the cause of the dementia, the physician must identify the pattern of the loss of skills and function and determine what functions the person can still perform. As a January 2019 AAPC article states, to assign the ICD-10 code, the documentation should correctly specify the root cause of the dementia.

Types of Dementia and Their Causes

Dementia occurs when the brain cells are damaged and cannot communicate with each other. Thinking, behavior and feelings can be affected when brain cells are unable to communicate normally. Progressive dementia types are not reversible and include:

  • Alzheimer’s disease: Alzheimer’s disease is the most common cause of dementia, accounting for 60% to 80% of cases. It is caused by genetic, lifestyle and environmental factors that affect the brain cells and causes memory loss and cognitive decline over time. There are four ICD-10 codes to report the condition:
    G30.0 – Alzheimer’s disease with early onset
    G30.1 – Alzheimer’s disease with late onset
    G30.9 – Other Alzheimer’s disease
    G30.9 – Alzheimer’s disease, unspecifiedICD-10 also offers secondary codes to distinguish between dementia without behavioral disturbances. For example, F02.80 Dementia in other diseases classified elsewhere without behavioral disturbance should be used to distinguish from dementia with behavioral disturbance – F02.81 Dementia in other diseases classified elsewhere with behavioral disturbance).
  • Vascular dementia: This is the second most common type of dementia. Vascular dementia can occur if a stroke blocks an artery in the brain. Other causes include conditions that damage blood vessels, affect circulation, and deprive the brain of vital oxygen and nutrients. Diabetes, high blood pressure, high cholesterol and smoking increase risk of vascular dementia. More than memory loss, vascular dementia is associated with problem-solving difficulties, slowed thinking, focus and organization.
    There are two ICD-10 codes to report vascular dementia:
    F01.50 Vascular dementia without behavioral disturbances
    F01.51 Vascular dementia with behavioral disturbancesICD-10 includes a note instructing reporting of the underlying physiological condition or sequelae of cerebrovascular disease for patients with vascular dementia. Also, code F01.51 includes an additional code Z91.83 to identify “wandering” (if applicable) in vascular dementia (
  • Lewy body dementia: This type of dementia involves a progressive decline in thinking, reasoning and independent function caused by abnormal microscopic deposits that damage brain cells. Common signs and symptoms include changes in thinking and reasoning, sleep disturbances, delusions and hallucinations, confusion and alertness that varies significantly from day to day or from time of day to another, slowness, tremors, and other parkinsonian movement features.
    The ICD-10-CM code for the disorder is G31.83 Dementia with Lewy bodies. 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

    Code G31.83 can be also used to indicate 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
  • Frontotemporal dementia: This is a group of dementias caused by progressive nerve cell damage in the brain’s frontal lobes or its temporal lobes. This causes deterioration in behavior, personality and/or difficulty with producing or comprehending language. Persons with a family history of frontotemporal disorders are more likely to have a genetic form of the disease. G31.09 Other frontotemporal dementia is the specific ICD-10 code that can be used to indicate a diagnosis for reimbursement purposes. An additional code should be used to identify Dementia with behavioral disturbance (F02.81)
  • Mixed dementia: Studies have revealed that many people with dementia have a combination of Alzheimer’s disease, vascular dementia and Lewy body dementia. Symptoms would depend on which type of dementia is dominant. Since there is no specific code for mixed dementia, an ICD-10 Monitor article points out that the provider should document both the Alzheimer’s and the other type of dementia (e.g., vascular dementia) and code the conditions separately.

Coding of dementia can be complex and confusing. An experienced medical coding company can help physicians report diagnosis using the correct ICD-10 codes. However, this depends on clear and precise medical record documentation by the physician. The documentation should identify the underlying cause of dementia whenever possible. In addition to the objective examination, the physician should document behavioral disturbances such as sleep disturbance, aggression, agitation, hallucination, delusion, and wandering. Good medical record documentation is essential to describe the severity of illness, to improve and measure quality of care, to provide better data for research, and for optimal reimbursement.

Julie Clements

Julie Clements, OSI’s Vice President of Operations, brings a diverse background in healthcare staffing and a robust six-year tenure as the Director of Sales and Marketing at a prestigious 4-star resort.

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