A 76-year-old woman is brought to the office by her daughter due to progressively worsening memory and language difficulties. The patient first started having memory problems and word-finding difficulties 5 years ago. She then began having difficulty balancing her checkbook and buying groceries. The patient became lost while driving to church last year and no longer drives. She is now dependent on her daughter for cooking and cleaning. Over the past 6 months, the patient's personality has changed from seeming apathetic to becoming more paranoid and agitated; she frequently claims to have seen her niece stealing from her purse. The patient recently developed urinary incontinence. She has a history of hyperlipidemia and osteoarthritis of the left hip and both knees. Blood pressure is 130/80 mm Hg and pulse is 90/min. Deep tendon reflexes are 2+ throughout, and she has preserved motor strength. The patient recalls none of 3 objects on memory testing and cannot draw a clock. Laboratory studies show normal electrolytes, lipid panel, TSH, vitamin B12, and complete blood count. Which of the following is the most likely diagnosis?
Clinical features of Alzheimer disease | |
Early |
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Late |
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This patient has evidence of dementia (ie, major neurocognitive disorder), including cognitive deficits that have led to impairment in activities of daily living (eg, preparing meals, cleaning). Her early and prominent memory symptoms, age of onset, and symptom evolution are classic for Alzheimer disease (AD).
AD is the most common cause of dementia in the United States and usually occurs after age 65. Death usually occurs within 10 years of diagnosis regardless of the treatment offered. Patients experience a progressive functional decline over the course of their disease. Later findings usually include personality and behavioral changes (eg, apathy, agitation), neuropsychiatric changes (eg, delusions, paranoia), neurologic manifestations (eg, myoclonus, seizures), and apraxia (eg, difficulty with motor tasks). Urinary incontinence may develop in later stages of AD, secondary to severe cognitive dysfunction.
(Choice B) In addition to the presence of dementia, a diagnosis of dementia with Lewy bodies requires the presence of ≥2 of the following clinical features: parkinsonism, fluctuating cognition, visual hallucinations, and rapid eye movement sleep behavior disorder.
(Choice C) Frontotemporal dementia typically presents with early and prominent behavioral/personality change and only later with prominent memory deficits. It typically manifests around age 60, demonstrably earlier than AD.
(Choice D) Normal pressure hydrocephalus (NPH) is characterized by abnormal gait, cognitive impairment, and urinary incontinence. Gait impairment is the most prominent clinical feature of NPH and appears early in its course; the gait is broad-based and shuffling. Gait impairment is not a classic characteristic of early AD (although it is commonly seen in older patients due to other conditions [eg, osteoarthritis]).
(Choice E) Vascular dementia typically presents with cortical- or subcortical-predominant symptom clusters, depending on the location of the precipitating vascular pathology. A stepwise decline is classic; however, deficits in executive function are much more severe than memory deficits early in the course of the disease. Vascular dementia is less likely in this patient due to the disease course (eg, memory deficits) and the absence of previous cerebral vascular disease.
Educational objective:
Alzheimer disease, the most common type of dementia in the United States, is characterized by early and prominent memory impairment. The differential includes dementia with Lewy bodies, frontotemporal dementia, and vascular dementia, as well as nondementing syndromes such as normal pressure hydrocephalus.