Dementia

Basics

Clinical syndrome defined by progressive deterioration involving one or more cognitive domains (language, memory, complex attention, perceptual-motor, social cognition) that is severe enough to interfere with activities of daily living and independence due to alteration in cortical brain function
A chronic and progressive form of organic brain syndrome
Over 50 different causes
Most common cause is Alzheimer dementia (between 60–80% of cases), followed by vascular dementia, mixed dementia, and dementia with Lewy bodies
Affects between 5–16% of individuals between age 65–85 and between 30–40% in people >85 yr old
Incidence of dementia has decreased in past few decades, although there has been a rise in absolute number of patients with dementia worldwide
Characterized by gradual decline in cognitive functioning:
- Generally evolves over period of years
- Course is highly variable, months to years in duration
- Rapid decline indicative of other causes, or rare rapid onset causes of dementia (prion diseases, progressive supranuclear palsy)
Variable hereditary
- Increased risk of Alzheimer disease in first-degree relatives of patients with Alzheimer
- Apolipoprotein ε4 is the only well-established mutation with late-onset Alzheimer

Primary dementia:
- Cortical (Alzheimer disease, frontotemporal dementia)
- Subcortical (Huntington disease, Parkinson disease, progressive supranuclear palsy)
Secondary dementia:
- Cerebrovascular disease (multi-infarct dementia)
- Toxic, metabolic, nutritional derangements
- Prion disorders (Creutzfeldt–Jakob or bovine spongiform encephalopathy and variants)
- Infectious agents (HIV, syphilis, encephalitis)
- Vasculitis (systemic lupus erythematosus, thrombotic thrombocytopenic purpura)
- Traumatic (chronic subdural hematomas, pugilistic dementia, chronic traumatic encephalopathy)
- Structural (normal pressure hydrocephalus, brain masses)
- Binswanger disease
Reversible (∼15%) causes include normal pressure hydrocephalus, medications, intracranial masses, and alcohol abuse syndromes
Pseudodementia:
- Depression in elderly can present with dementia-like symptoms
- Common in mildly demented patients, look for pin-point event with short duration of symptoms
- Generally with history of psychiatric conditions, emphasis on failures and disabilities

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