Dementia

Key Features

Essentials of Diagnosis

• Progressive decline of intellectual function

• Loss of short-term memory and at least one other cognitive deficit

• Deficit severe enough to cause impairment of function

• Not due to delirium or psychiatric disease

• Major risk factors

  • Age

  • Family history

  • Lower educational level

  • Diabetes mellitus

  • Cigarette smoking

  • Hypertension

  • Obesity

  • History of significant head injury

  • Hearing loss

  • Female sex

• Vitamin D deficiency and chronic sleep deprivation may also increase the risk for dementia

General Considerations

• Defined as a progressive, acquired impairment in multiple cognitive domains, at least one of which is memory, that is severe enough to compromise work or social life

• "Mild cognitive impairment" describes a decline that has not resulted in a change in the level of function

• Patients have little cognitive reserve and can have acute cognitive or functional decline with a new medical illness

• Dementia is distinct from delirium and depression and other psychiatric disease, and in the elderly may coexist with them

  • Delirium is an acute confusional state that often occurs in response to an identifiable trigger

    • Typically involves fluctuating level of arousal and improves after removal or treatment of the precipitating factor

  • Depression and other psychiatric disease sometimes lead to complaints of impaired cognition (pseudodementia)

    • Symptoms should improve with appropriate psychiatric treatment

    • Evidence suggests that a persistent, untreated mood disorder may predispose to the development of an age-related dementia

    • Psychiatric symptoms can clearly exacerbate cognitive impairment in patients who already have dementia

• Rapidly progressive dementia (eg, Jakob-Creutzfeldt disease) is defined as obvious decline over a few weeks to a few months

Demographics

• Prevalence of Alzheimer dementia in the United States

  • Doubles every 5 years in the older population, reaching 30–50% at age 85

  • Predicted to be 15 million by 2060

• Typically begins after age 60, and the prevalence doubles approximately every 5 years thereafter

• Women suffer disproportionately, as patients (even after age adjustment) and as caregivers

• Alzheimer disease accounts for two-thirds of cases of dementia in the United States, with vascular dementia (either alone or combined with Alzheimer disease) accounting for much of the rest

Clinical Findings

Symptoms and Signs

• Memory impairment with at least one or more of the following

  • Aphasia (typically, word finding difficulty)

  • Apraxia (inability to perform previously learned tasks)

  • Agnosia (inability to recognize objects)

  • Impaired executive function (poor abstraction, mental flexibility, planning, and judgment)

• Alzheimer disease

  • Typical earliest deficits are in memory and visuospatial abilities

  • Social graces may be retained despite advanced cognitive decline

  • Personality changes and behavioral difficulties (wandering, inappropriate sexual behavior, aggression) may develop as the disease progresses

  • Hallucinations, delusions, and symptoms of depression often occur as dementia worsens

  • End-stage disease characterized by

    • Near-mutism

    • Inability to sit up

    • Inability to hold up the head

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