DEMENTIA   56A

A 73-year-old man is brought in by his wife, who is concerned about his worsening memory. A retired engineer, he has recently been getting lost in the neighborhood where he has lived for 30 years. He has often been found wandering and been brought home by neighbors. When asked about this, he becomes upset and defensive and says that he was just trying to get some exercise. He has had trouble dressing himself and balancing his checkbook. A physical examination is unremarkable, except that he scores 18 of 30 points on the Mini-Mental Status Examination. A metabolic evaluation is normal. A computed tomography (CT) scan of the head shows generalized brain atrophy, although perhaps only what would be expected for his age, without focal lesion. He is diagnosed with dementia, likely from Alzheimer disease.

What are the salient features of this patient’s problem? How do you think through his problem?

Salient features: Age older than 65 years; worsening memory; wandering; loss of abilities in activities of daily living (ADLs); abnormal cognitive function test; normal metabolic evaluation; brain atrophy on head imaging studies

How to think through: Patients with impaired cognitive function and personality change are commonly encountered in both inpatient and outpatient settings. Before dementia can be diagnosed, delirium must be excluded. What are the distinguishing features of each? (Delirium is acute in onset, waxing and waning, with inattention and either an altered level of consciousness or disorganized thinking. Dementia is subacute in onset and marked by progressive decline in short-term memory and at least one other cognitive domain.) What other disorders may mimic dementia? (Medication toxicities, depression and psychotic disorders, thyroid disease, vitamin B₁₂ deficiency, HIV, syphilis, malignancy.) After Alzheimer disease is diagnosed, how should the patient be treated? (The effectiveness of cholinesterase inhibitors is modest at best. Close attention to the patient’s level of function and safety become paramount, with ADL and I-ADL assistance and emphasis on structure and routine.) The use of antipsychotic medications to control difficult behavioral symptoms is controversial. What are the two key toxicities of these medicines in patients with dementia? (Arrhythmia from prolonged QT interval and stroke.) Complications of end-stage dementia include anorexia, dysphagia, and aspiration; hospice care at this stage is often appropriate.

DEMENTIA   56B

What are the essentials of diagnosis and general considerations regarding dementia?

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 delirious (no waxing or waning in level of consciousness)

General Considerations

A progressive, acquired impairment in multiple cognitive domains, at least one of which is memory

The deficits must be significant enough to interfere with work or social life

Frequently coexists with depression and delirium

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

Risk factors include older age, family history, lower educational level, and female sex

Alzheimer disease most common cause in the United States followed by vascular dementia

Prevalence of Alzheimer disease increases precipitously with increasing age

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