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DIAGNOSIS OF DEMENTIA

What are the Clinical Features of Dementia

Dementia is a chronic impairment of intellectual functioning of sufficient severity to interfere with social or occupational functioning. Patients with dementia manifest multiple cognitive deficits manifested by memory impairment (impaired to learn new information or to recall previously learned information)and one (or more) of the following cognitive disturbances: aphasia (language disturbance), apraxia (impaired ability to carry out motor activities despite intact motor function), agnosia (failure to recognize or identify objects despite intact sensory function), and disturbance in executive functioning, (i.e., planning, organization, sequencing, abstracting). Additionally, the diagnosis of Alzheimer's type dementia requires that illness have a gradual onset over one or two years and progressive course and that the cognitive deficits are not due to other conditions. The diagnosis of vascular dementia necessitates the presence of focal neurological signs and symptoms or laboratory evidence of cerebrovascular disease judged to be etiologically related to the disturbance.

What is the Pattern of Progression of Dementia?

In the earliest stages of dementia, patients manifest loss of higher order functional skills such as the capacity to perform social or work activities outside the home. Impaired memory, particularly for new events, is usually the reason for initial consultation with a physician. In the moderate stages of dementia, visual-spatial impairment becomes prominent as indicated by the patient's inability to draw geometric figures. Clinically, visual-spatial impairment may impair driving abilities. As the disease progresses, word-finding difficulties, personality alterations, hallucinations and delusions may occur as well as behavioral disturbances including wandering, sleep disturbances and combativeness. At this stage, loss of some of the basic self care functions occur such as the inability to groom and dress appropriately. In the late stages of dementia overt aphasia may result in impaired communication and gait disturbances and urinary incontinence occur. Eventually the patient becomes chair or bedbound. Finally, the patient experiences an inability to eat and swallow properly, instead holding food for long periods in the oral cavity resulting in undernutrition and the risk of aspiration. The duration from onset of symptoms to the bedridden non-communicative state is variable but usually develops over five to seven years.

What are the Common Causes of Dementia?

First, it must be understood that senility is not synonymous with dementia. Whereas senescence and senility refer to the normal aging process, dementia denotes a pathological process. Most often, dementia is caused by Alzheimer's Disease, a diffuse degenerative process, or by multi-infarct dementia (MID), due to multiple small subcortical or cortical infarcts or lacunes. Symptoms suggestive of MID include: history of hypertension, history of stroke or transient ischemic attack, sudden onset, stepwise deterioration, and focal neurological symptoms and signs. Other causes of dementia are important because of their potential for palliation or rarely, for complete reversibility. Longitudinal studies have pointed out that less than 4% of patients with dementia, exclusive of depression, have a completely reversible illness. Drugs, metabolic abnormalities, and subdural hematomas, though less common than Alzheimer's disease, may be causative of dementia. Structural or mass lesions due to brain tumors, and normal pressure hydrocephalus may also present as a dementing illness.

What are the principal historical facts to elicit in diagnosing dementia?

The history should focus on acuity of onset, duration, course of the illness over time, severity as indicated by functional status, presence of the underlying organic illnesses, use of drugs associated with these disorders, and the patients support system. Other questions are directed at specific cognitive deficits that result in confusion:. What was the patient's premorbid mental status? Is there a remote or recent history of memory, orientation, or speech impairment? Have there been periods of lethargy or stupor? When did the process begin? Have the patient's symptoms fluctuated? Is there a history of falls, head trauma, focal neurologic symptoms, seizures, alcohol or other drugs of abuse? What prescription and over-the-counter medications does the patient take?

What are the Components of the Physical and Mental Status Examination?

Attention should be tested by observing the patient's responses to routine history-taking and by asking the patient to perform specific tasks: performing serial subtractions backward, spelling words backwards, and, for patients whose level of education is a barrier to tests of spelling and math, reciting the days of the week backward. Disorientation to time is tested by asking questions related to the day, date, month, and year while disorientation to place is tested by asking about the city, state, country, and name of the hospital where the patient is being examined. In testing memory, registration is first tested by asking the patient to immediately repeat the names of three objects, such as hat, car, and tree. Three minutes later ask the patient to repeat the same objects. Remote memory should be tested by asking about events with which the patient should be familiar: city of birth, age and birthdates of children, wedding anniversary, and other similar questions. The nature of the patient's speech should also be observed. Is the patient drowsy, stuporous, or comatose? Does the patient demonstrate restlessness, tremulousness, or paucity of movement?

What is the Value of Neuropsychologic Testing?

Screening tests of cognition and affect have received considerable attention over the past decade because of their brevity and because they offer specific instructions for physicians with limited experience in mental status testing. Among these tests are the Mini- mental State Examination (MMSE) and the Blessed Tomlinson Scale used to assess cognition and the Geriatric Depression Scale used to assess affect. Although beneficial in following the course of illness, they are not a substitute for a detailed clinical mental status history and examination or a substitute for formal neuropsychologic testing. Formal neuropsychologic tests are most useful in the mildly impaired patient suspected of dementia because of subtle cognitive deficits but prior to the onset of overt functional deficits. Administered by a psychologist, this examination typically consists of two to four hours of tests designed to assess brain function in several dimensions: general intelligence, verbal and visual memory, attention and concentration, language, fine motor skills and visual spatial skills. Although performance on one examination may suggest impairment, the administration of two are more tests at six to nine month intervals is more useful in that the magnitude and pattern of deficits as they change over time can be suggestive of Alzheimer's Disease versus MID.

Which Laboratory and Radiological Tests Should be Ordered?

Patients suspected of dementia should always undergo the following tests: complete blood count, electrolyte panel, metabolic panel, serologic tests for syphilis, thyroid function tests, B 12 and folate levels, urinalysis, electrocardiogram and chest radiograph. Other tests should be obtained when specific diseases are suspected. For example, the sedimentation rate is warranted when symptoms suggest giant cell arteritis or another form of vasculitis. Tests of lyme disease should be considered in adults with dementia accompanied by rheumatic, cardiac or peripheral neurologic findings. An EEG cannot reliably distinguish dementia from normal aging and is therefore of little value as a routine test in the evaluation of dementia. Computerized Tomography or Magnetic Resonance Imaging of the brain is useful in selected patients when in or out subdural hematomas, mass lesions, or normal pressure hydrocephalus when suggested by specific clinical features: onset in less than six months, history of malignancy, focal neurologic deficits, and recent onset of a seizure disorder.

TREATMENT OF DEMENTIA

What are the Elements of Nonpharmacologic Treatment of Dementia?

In most instances, dementia is due to Alzheimer's or Multiple infarcts. In these patients, treatment is palliative rather than curative. However, over 30% of patients with dementia have more than one illness contributing to the dementia state. Treatment of these concomitant disorders provides temporary improvement in 28% of 200 patients and improvement is sustained for at least one year in 14%. Thus patients with irreversible dementia due to Alzheimer's and MID may improve in function with comprehensive management, although their cognitive status continues to inexorably deteriorate. In the case of Alzheimer's Disease, practitioners should assist the patient's family in providing a supportive environment to compensate for the patient's disabilities, minimize the cognitive side effects of medications, and maximize function of organs other than the brain by treating concomitant illnesses. Maintenance of nutrition, and exercise are vital, as is social stimulation. Additionally, one must assist and counsel caregivers, by providing respite when needed as well as consultation on the legal and ethical issues that arise over the course of dementia.

Family and caregiver counseling is a critical component of he management of the demented patient. Families must be advised of the community support services and day care centers and other forms of respite. To avoid crises, families should be given advance notice of potential legal and ethical issues that arise over the course of dementia. Therefore, issues of durable power of attorney and other forms of advance directives should be discussed early in the illness. One of the difficult but predictable issues for families is whether to use artifical feeding when the demented patient progresses to the point that oral intake is insufficient or unsafe because of aspiration. The physician should try to get the caregivers to decide whether artifical feeding will be used before a decision has to be made.

What Drugs are Useful in Treating Dementia?

Drug useful in treatment of dementia fall in to two categories: drugs aimed at managing behavioral problems, such as combativeness, agitation and sleeplessness; and drugs aimed at improving cognition. A review of controlled trial of neuroleptic treatment in dementia showed that 18% of dementia patients benefited but only modestly. No single neuroleptic is superior. Although there is little scientific evidence for the widespread use of these agents, neuroleptics are superior to placebo in controlling anxiety, suspiciousness, uncooperativenes and hallucinatory behaviors. It is safest to use these drugs only if signs and symptoms of psychosis or significant excitement and agitation complicate management. On the contrary, repetitive behaviors such as aimless wandering, pacing and calling out are usually less responsive to neuroleptics and they have little effect on poor self care, social withdrawal, wandering and cognition. In these instances, the adverse effects of neuroleptics (sedation, orthostatis, Parkinsonism, falls and urinary retention) may reduce functional status outweighing any benefit. When antipsychotic agents are used, butyrophenones or other high potency agents rather than the more sedating phenothiazine agents are indicated. The latter may be preferable if sedation is needed. Other psychotropics including benzodiazepines, betablockers and the antidepressant, trazodone, have been used also to induce sleep and control agitation. In summary, agents for behavioral control should be used as a last resort. When used, the practitioner should avoid combining more than of these agents concurrently.

Drugs aimed at altering the progressive cognitive decline in dementia have been the subject of multiple clinical trials. In multi-infarct dementia (MID), the principal aim is to prevent further brain infarcts by use of aspirin and antihypertensives, though data to support efficacy are lacking. Vasodilators in MID have shown little benefit. Recently attention has been directed at developing effective therapy for Alzheimer's Disease. Categories of medications proposed to treatment Alzheimer's include cholinomimetics to restore deficiencies of acetyl choline in the brain; neuropeptides to induce cortical interneuronal transmission, nootropic agents to stimulate neuron metabolic activity; vascular agents to improve blood flow; calcium blockers to prevent the accumulation of calcium in injured neurons; and miscellaneous agents including nerve growth factors and cell membrane stabilizers.

What is the Benefit of Acetylcholine Esterase Inhibitors?

For clinical use, most progress in the treatment of Alzheimer's Disease has been made with acetylcholine esterase inhibitors. Tetrahydroaminoacridine (Tacrine), recently released in the United States, has been marketed for patients with mild to moderate disease. Recent randomized trials of tacrine in England, Canada, and the United States provide a basis for using this medication in some patients. Of note, patients studied have had mild to moderate dementia (mean Mini-Mental State Examination score of 16 to 18). When seen, improvements have been in cognitive rather than in behavioral function. In summary, studies show that tacrine in doses of 40 to 160 mg per day :

  1. benefits a small subgroup of patients with Alzheimer's Disease;

  2. improves cognition or slows rate of cognitive decline over a short period, but the magnitude of the improvement is small ;

  3. commonly causes hepatotoxicity that is usually reversible; and most important,

  4. clinical use requires a clear commitment from patients, caregivers, and clinicians because of the need for careful monitoring.

On the other hand, the duration of the effect of Tacrine is unknown since studies have been of short duration and because study populations have been highly selected, its effectiveness in severe dementia or in demented patients with co-morbidities is unknown.

 

 

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