Dementia (Case 53)

Published on 24/06/2015 by admin

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Last modified 24/06/2015

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Dementia (Case 53)

Jessica L. Israel MD

Case: The patient is a 76-year-old woman who managed a small restaurant with her husband for many years. He died 2 years ago, and now her son does most of the day-to-day work at the restaurant. She has a history of osteoarthritis and well-controlled diabetes mellitus. During the history and physical exam at the office visit, she is pleasant and cooperative. She tells you that she does not know why her son brought her to see you. She says she feels fine.

When you step out of the examination room, her son and his wife are waiting to talk with you. They tell you that they are worried about Mom and that she just hasn’t been the same since her husband died. She now lives alone. She vehemently resists accepting any help and she argues with them if they try to help her. Her son has noticed that her pocketbook is full of bills that she hasn’t paid and old receipts for things she bought many months ago. She has been forgetting appointments and sometimes even forgetting the names of their regular customers at the restaurant. She seems to repeat herself, asking the same question over and over. Some evenings, they believe, she doesn’t bother to cook or eat dinner. They are very worried that she might have a problem with her memory.

Differential Diagnosis

Alzheimer disease

Vascular dementia

Lewy body dementia

Frontotemporal dementia

Mild cognitive impairment

Delirium

Depression

 

Speaking Intelligently

 

PATIENT CARE

Clinical Thinking

• When evaluating a patient in whom a diagnosis of dementia is possible, it is important to recognize that this is a common disease; it occurs in 6% to 8% of those aged 65 years and over, and in some estimates can affect up to 50% of those older than 85 years.

• Dementia is often not diagnosed, simply because of the time it takes to address this problem in the outpatient setting, and the counterpressures to address other medical problems in the same patient encounter.

• An early diagnosis, with initiation of treatment, offers the patient the best chance of slowing the progression of the disease, and of maintaining function and quality of life for as long as possible.

History

• Dementia, in general, refers to a group of disorders that cause a significant decline in two or more areas of cognitive functioning. At least one of these has to be severe enough to cause a functional decline.

• Some patients have insight into their memory loss and its consequences, but many do not. Most often, a detailed history obtained via a close family member or contact is needed.

• There are useful standardized instruments such as the Functional Activities Questionnaire that informants can complete.

• Comparing the person’s present function to his or her previous level of function is important. Commonly, instrumental activities of daily living (IADLs) are impacted by the cognitive changes. IADLs include such activities as using the telephone and preparing food.

• Although short-term memory loss is commonly described, changes can also be more subtle, such as word-finding difficulty or problems completing a crossword puzzle. Because dementia is often diagnosed in later, more moderate stages, families might also describe more significant behavioral changes such as paranoia, hoarding, auditory or visual hallucinations, wandering, and frequent agitation.

• The key is that there has been a cognitive behavioral change in this patient, and this change affects her everyday functioning.

Physical Examination

• It is possible to have a diagnosis of mild cognitive impairment, Alzheimer dementia, or frontotemporal dementia, and to have a completely normal physical examination.

• Physical findings, if present, may suggest other types of dementia.

• Focal neurologic findings might be found in vascular dementia.

• Rigidity, tremor, or gait disturbance can be seen in patients with Lewy body dementia.

Tests for Consideration

Vitamin B12 concentration will diagnose B12 deficiency. If the B12 concentration is in the low-normal range, a methylmalonic acid concentration may be helpful. Vitamin B12 deficiency can present with cognitive changes and neurosensory changes in the lower extremities.

$21

TSH will be elevated in hypothyroid patients. Clinically, patients with hypothyroidism may present with a history of slowed mentation. Other symptoms at presentation could include dry skin, weakness, constipation, joint pain, or an abnormal gait, but in many older adults, because of the slow and gradual progression of symptoms (if any are present), the diagnosis may not be obvious.

$24

• A rapid plasma reagin (RPR) titer may be positive in patients with neurosyphilis. Patients with this disease many also present with cognitive changes. The RPR is a non-treponemal test, such that a confirmatory treponemal test (e.g., the fluorescent treponemal antibody, or FTA test) should be performed. If the FTA test is positive and neurosyphilis is considered, a CSF examination should be performed.

$6

• It is possible to test for the apolipoprotein E*4 (APOE*4) allele on chromosome 19. This allele increases a person’s risk of Alzheimer disease and decreases the age of onset in a dose-related fashion. The highest risk exists for those with an apolipoprotein E 4,4 genotype. Using this gene as a prognostic test is problematic, however, as it is neither sensitive nor specific. It may be used (rarely) to increase diagnostic confidence.

$435

Folstein Mini-Mental State Examination (MMSE): This is the most commonly used test to assess cognitive function. It assesses multiple cognitive domains including orientation, recall, registration, calculation, attention, and visuospatial skills. The results of this test may be skewed by the level of education attained by the patient.
Also, this test is difficult to administer to hospitalized patients because many of the questions are about orientation, and hospitalized patients often are not aware of their specific location within the hospital, even if there is no cognitive compromise. A score of less than 24, however, warrants further attention in the workup of dementia.

• The clock-drawing test assesses executive functioning and visuospatial skills. In this test the patient is asked to draw the face of a clock, including the numbers, and then to show the time as either 11 o’clock or 10 o’clock. If the evaluator then divides the clock into four quadrants, it is most common to find errors in the fourth quadrant, between 9 and 12 o’clock.

• The mini-cog is a combination of the clock-drawing test and the three-item recall section of the original MMSE. This combination has been recently evaluated and validated in older adults. It offers the advantage of allowing administration to patients whose native language is not English, or to those with less than a high school education. In general, because short-term memory is one of the earliest findings in demented patients, the three-item recall portion of this test is the single best screening tool. The patient is asked to repeat three words after hearing them and then to recall these words after 1 minute.

 

IMAGING CONSIDERATIONS

→ CT scan of the head (without contrast) is usually considered optional. However, it can be considered for patients with a post-acute change in their cognitive status (meaning that symptoms have occurred for <2 years). It may also be helpful for a patient with focal or asymmetric neurologic findings on examination, one who has had a recent fall or head injury, or one with the triad of symptoms that suggest a diagnosis of normal-pressure hydrocephalus (urinary incontinence, unsteady gait, and cognitive compromise).

$334

→ PET (positron emission tomography)

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