Dementia due to Alzheimer disease
Demência devida à doença de Alzheimer
CategoryDefinition
Dementia due to Alzheimer disease is the most common form of dementia. Onset is insidious with memory impairment typically reported as the initial presenting complaint. The characteristic course is a slow but steady decline from a previous level of cognitive functioning with impairment in additional cognitive domains (such as executive functions, attention, language, social cognition and judgment, psychomotor speed, visuoperceptual or visuospatial abilities) emerging with disease progression. Dementia due to Alzheimer disease may be accompanied by mental and behavioural symptoms such as depressed mood and apathy in the initial stages of the disease and may be accompanied by psychotic symptoms, irritability, aggression, confusion, abnormalities of gait and mobility, and seizures at later stages. Positive genetic testing, family history and gradual cognitive decline are suggestive of Dementia due to Alzheimer disease.
Coding Note
Diagnostic Criteria
- All diagnostic requirements for Dementia are met.
- Dementia is presumed to be attributable to underlying Alzheimer Disease (8A20) based on quantified clinical assessment or standardized neuropsychological/cognitive testing, neuroimaging data, genetic testing, medical tests, family history, and/or clinical history.
- Early clinical history is typically characterized by gradual onset, progressive memory problems and word finding difficulties, as well as mild functional impairment. The most common form of Alzheimer Disease begins with neuronal impairment in the medial temporal lobes (the brain regions involved in memory formation). As Alzheimer Disease progresses and affects other brain regions, neurocognitive symptoms worsen. Atypical forms of Alzheimer Disease are also characterized by progressive neurocognitive and functional impairment, with initial neurocognitive symptoms often corresponding to the brain region(s) initially affected (e.g., visual processing impairment in posterior cortical atrophy, etc.).
Note: For all forms of Dementia due to Alzheimer Disease, the diagnosis 8A20 Alzheimer Disease should also be assigned.
For Dementia Due to Alzheimer Disease whose onset is unknown or unspecified, the following diagnosis may be appropriate:
6D80.Z Dementia Due to Alzheimer Disease, onset unknown or unspecified
- All diagnostic requirements for Dementia Due to Alzheimer Disease are met.
- The onset of neurocognitive, functional, and/or behavioural symptoms associated with Alzheimer Disease is unknown or unspecified.