Dementia
CASE
An 82-year-old retired schoolteacher has had increasing problems functioning at home. She stopped driving a year ago, after she became lost on the way home from church. Nine months ago, her daughter took over paying the bills and grocery shopping, when she realized her mother could no longer balance her checkbook or make a shopping list. Her neurologic examination is unremarkable, except for a mini-mental status examination score of 16 out of a possible score of 30.
WHAT IS THE NATURE OF DEMENTIA?
Dementia is a loss of intellectual ability that interferes with a person’s ability to function at work or in a social situation. It is chronic, developing over months and years. It affects multiple components of cognition such as judgment, language, initiative, spatial abilities, and memory. There are many causes of dementia, the most common being Alzheimer disease (AD) and multi-infarct dementia (MID). Treatments for AD have become available, increasing the importance of establishing a diagnosis.
DIAGNOSING DEMENTIA
Obtain a careful history. A careful history from the family is essential. Never depend on the patient’s account alone. Patients with dementia may lack insight into their problems.
When did problems first begin and how rapidly have they progressed? Include questions about working, driving, shopping,
doing the checkbook, and self-grooming. Specific examples of functional problems are very useful in diagnosis.
Is there a problem with language? Does the patient have trouble finding words, or does the patient use unusual words (paraphasic errors)? These suggest a dominant hemisphere language area abnormality.
Is there a change in personality (i.e., more irritable or more placid)? Is the patient impulsive in decisions, or in conversation with others? Such changes may be seen in frontal lobe dementias, as well as in later stages of AD.
Has the patient lost initiative (e.g., given up hobbies or suggesting where to go on weekends)? This is seen with frontal lobe disease.
Does the patient get lost in the house, or lose the car in a parking lot? This may suggest nondominant parietal lobe dysfunction.
Is the patient ataxic or incontinent? Normal pressure hydrocephalus (NPH) causes the triad of dementia, ataxia, and incontinence. Gait disorders may occur in other dementias.
Is there evidence of depression? In the elderly, depression may mimic dementia and respond to antidepressants.
Are there medications, toxins, or “sleeping pills” that could be compromising intellect? Substance abuse (e.g., alcohol) and medication toxicity frequently are under-diagnosed in the elderly. Statins may occasionally cause memory disorders, and are commonly prescribed.
Are there medical illnesses that may have an impact on cognition? Is the patient positive for the human immunodeficiency virus (HIV), which is a major cause of dementia in younger adults?
Is there a family history of dementia? Often, this may be underplayed by the family. Ask about “senility” or failing faculties in the elderly. First-degree relatives of patients with Alzheimer disease have an increased lifetime risk of developing Alzheimer disease.
Is there a history of stroke, hypertension, diabetes, or other vascular risk factors? These may point to multi-infarct dementia.
Are there concurrent parkinsonism, mental fluctuations, and formed visual hallucinations? Lewy body dementia has these features.
Is there progressive headache, or focal neurologic symptoms, to suggest a mass lesion?
DEFINE THE MENTAL STATUS
The mental status is a bedside evaluation of cognitive function. Obviously this is only one measure of cognitive function. Extensive neuropsychiatric evaluation may be needed to precisely evaluate patients for deficits in different functional areas. There are readily available brief mental status tests (e.g., Folstein mini-mental status, short test of mental status, frontal assessment battery) that can be used as screening tools, and are quantitative. They can be used to quantify and track function over time. The definition of the mental status consists of the following components:
State of consciousness. If the patient is not fully awake, one should suspect a metabolic disorder, or a space-occupying lesion.
Delirium is an acute, fluctuating mental state with prominent agitation, and hallucinations, as well as perceptual errors.
Inattention.
Fluctuating symptoms.
Disturbances in sleep.
Prominent perceptual abnormalities.
Increased autonomic activity.
Coma is when a patient has no conscious interaction with his or her environment.
Stupor refers to a patient who interacts only when stimulated, but otherwise is indifferent to his or her environment.
Obtundation is a term readily used by medical residents. However, it is one that lacks medical definition, and should be avoided.
Observe what the patient does when left alone, and when you interact with the patient. Does the patient notice individuals in the room? Does he or she say hello and offer to shake hands? Check for attention by digit span (counting backwards from 100 by sevens; 20 by threes), or by having the patient recite the months of the year backwards. If a patient is inattentive, it will be difficult to interpret the rest of the mental status examination.
Orientation to place, person, and time. Is the patient able to tell the year, date, and day? Do they know where they are, the floor they are on, why they are there? Do they know who you are, or what you do?
Aphasia (see Chapter 4). Test naming, repetition, and evaluate spontaneous speech. Have the patient describe his or her occupation or favorite hobby in detail. Test his or her ability to read a newspaper, write when dictated to.
Memory. Can the patient remember a phone number of 7 digits? Can the patient repeat four objects immediately? Working memory or immediate recall is tested in this way. Retrieval of material after a few minutes is one measure of long-term memory (e.g., remembering four objects after doing another task).
Calculation. Have the patient do simple mathematical problems. Acalculia occurs in dominant hemisphere parietal disorders (angular gyrus).
Abstraction. Ask questions such as, “How are a ball and an orange alike?” or “What do a bathtub and the ocean have in common?”
Judgment. What would they do in the Denver airport with a dollar in their pocket (no cell phones, no debit, or credit cards)?
Pictures. How well can the patient interpret a picture in a magazine? Is there focus on one tiny part, and an inability to integrate it (asimultagnosia)? Does the patient have problems drawing or copying designs (constructional apraxia)?
Mood and thought content. Is the patient sad or inappropriately cheerful? Fearful or paranoid? Active or apathetic? Personally neat or sloppy? Is the patient’s affect labile (does it vary from moment to moment)? Does the patient tell inappropriate jokes?
PERFORM CAREFUL GENERAL AND NEUROLOGIC EXAMINATIONS
For the general examination, is there evidence of liver, kidney, lung, heart, adrenal, or thyroid disease?
Patients with general medical conditions may have cognitive dysfunction.
Is the blood pressure elevated? Is the heart rhythm regular?
Hypertension and atrial fibrillation are markers for multi-infarct dementia.
Are there focal neurologic signs, papilledema, or upgoing toes? Are the reflexes brisk?
Focal signs other than frontal release signs should signal a search for focal brain lesions such as stroke, tumor, infection, inflammation, and the like.
Check vision and hearing. Test for smell. Symptoms of dementia are made worse by sensory deprivation.Related posts:
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