Alzheimer's s Disease: An Overview.

Once considered a rare disorder, Alzheimer's disease (AD) is now a major public health problem. The prevalence of this disease is expected to double over the next 20 years due to the aging of the population. The devastating effects of this disease reach far beyond the patient. AD has a profound effect on the millions of spouses, relatives and friends who make up the extensive network of care providers. The significant emotional and social consequences for the patients and the family are enormous. As the disease progresses, the impact on caregivers in terms of physical and emotional burden, financial and employment status will continue to be devastating. The pivotal role of health care workers with families and caregivers will become even more crucial as more cases are identified.

Attention to the early diagnosis of Alzheimer's disease and the continued development of a public environment that encourages appropriate assessment is essential. These steps are important for detecting reversible dementias, for helping patients and families plan and for determining the actual prevalence of dementia for public health and health care considerations. Early recognition will become even more critical as treatments become available that slow, halt, or reverse the progression of the disease.

DIAGNOSIS

Although Alzheimer's disease is the most common type of dementia, especially in older people, the patient may have some other type of dementia. Characteristic features of these conditions are listed in the Fact Sheets section of this special feature.

The diagnosis of AD is relatively simple. One first needs to ascertain that the patient does have a memory problem that is global (ie, affecting trivial as well as important events or facts) and interfering with the activities of daily living.

Secondly, one needs to confirm the presence of cognitive deficits such as anomia (an inability to name objects), agnosia (an inability to recognize objects), and apraxia (an inability to carry out coordinated voluntary activities even though there is no muscle weakness). In the presence of these four A's (Amnesia, Anomia, Agnosia, and Apraxia), and an insidious onset, the likelihood of the patient having AD is as high as 80%. The diagnostic process need not be lengthy provided the clinician keeps the interaction with the patient and relatives focused. Selected algorithms and guidelines, developed by professional organizations, associations, or societies to facilitate the diagnosis of dementing diseases, are presented in this section.

Laboratory investigations and brain imaging techniques are neither used to confirm the diagnosis nor to exclude it, but merely to detect the presence of other pathologies that may worsen the patient's cognitive functions. This is one fundamental change that has occurred in the past few years. It used to be emphasized that all other possible causes of cognitive impairment be excluded before making a diagnosis of Alzheimer's disease; in other words, the diagnosis was made by exclusion. Now the tendency is to make a diagnosis if certain features are present, ie, the four A's and an insidious onset. The diagnostic process is therefore one of inclusion, and no longer one of exclusion.

It is nevertheless important to diagnose other conditions that may worsen the patient's condition, as the successful management of these conditions is likely to improve the patient's ability to carry on with the daily activities and improve the quality of life.

In addition to the cognitive deficits, patients with AD, even in the early stages, have evidence of impaired judgment. The management of these patients, therefore, should include provisions to prevent the patient from self-harm and to protect the financial assets. These are difficult and sensitive issues that need to be addressed as early as possible.

STAGING OF THE DISEASE

The classification of Alzheimer's disease in three stages is very useful.

Stage I

The cognitive impairment is so slight that many may not think there is anything wrong with the patient or that there is only some slight eccentricity. In this stage only people who are quite intimate with the patient are able to appreciate the changes in personality and cognitive ability.

Stage II

The degree of cognitive impairment is such that even those who had never met the patient before can appreciate that the patient has cognitive dysfunction.

Stage III

In addition to the cognitive deficit, the patient has evidence of physical deficits. Unsteadiness, repeated falls, and urinary incontinence are not uncommon.

Patients in Stage I need to be protected from predators in society who may readily take advantage of the patient's impaired judgment to acquire various assets. In Stage II, the patient should be protected from self-harm, as the danger of some activities may be not readily appreciated. Finally, in Stage III, the patient needs, in addition, usual nursing care.

MANAGEMENT

The management of patients with this disease has changed radically over the past few years. Specific medications are now commercially available. The FDA has approved donepezil (Aricept), rivastigmine (Exelon), and galantamine (Reminyl) for the treatment of patients with AD. When administered in a timely manner, they not only slow the rate of deterioration, but also actually improve the patient's condition. Because they are acetylcholinesterase inhibitors, it is important that therapy be started as early as possible. However, this should not deter clinicians from trying these medications even in patients with advanced Alzheimer's disease, as the safety profile of these medications is good and there are a few reported cases of improvement even in patients with severe Alzheimer's disease. In the Medication Update section we have included an up-to-date, unbiased, evidence-supported profile of these medications.

The management of the patient with AD does not end once the diagnosis is made. In fact, this is the beginning of a long process for the patient, family, and primary care physician. All must be prepared to face the wide variety of issues that are likely to arise during the many years after the diagnosis of this dementing disease has been established. Anticipation and avoidance of crises are much more effective than reaction to these crises. Family and caregiver education is therefore of paramount importance; both pay large dividends in terms of time saved at a later stage. Conflicts and crises often occur because the family and caregivers have not anticipated the problem. These catastrophic events are an example par excellence where an ounce of prevention is better than a pound of cure.