Alzheimer’s Disease is a disease of the future. With the growing aged population, this disease, which affects primarily the elderly, will become of increasing relevance to the medical profession. Also, the high frequency of Alzheimer’s, and the high cost in labor, money, and material of caring for its victims shall put considerable burden on the society as a whole. Here, however, these issues are not going to be debated. Instead the pathology of Alzheimer’s will be reviewed to the extent it is known today.

Alzheimer’s disease in many ways is not yet defined. It is a progressive disease afflicting between 5 and 15 percent of people over 65. Additionally, it is not restricted to the elderly, reportedly having presented in teenagers. Prior to 1960, the term Alzheimer’s was reserved for presenile dementia’s resulting in death within 5 years where the classical neuroanatomic changes were seen upon autopsy. Currently, there is still considerable debate as to whether the disease called Alzheimer’s in the elderly is the same disease as that called Alzheimer’s in younger people. In addition, recent and past research into Alzheimer’s has been in geared toward defining the disease as much as describing the disease process. Presently, diagnosis of Alzheimer’s disease is based on characteristic dysfunction’s of the individual and on brain biopsy or post-mortem brain autopsy looking for cortical degeneration, a preponderance of plaques, and neurofibrillary tangles.

Exactly what causes Alzheimer’s disease is unknown. Aging has been blamed for Alzheimer’s. The preponderance of cases being among the aged supports this theory but the existence of Alzheimer’s scattered across the population not explained. Transmissible agents such as viruses yet undiscovered have been put down as a possible cause of Alzheimer’s. Others claim that there is a genetic component, and the presence of a similar if not identical disease in victim’s of Down’s Syndrome provide a foundation for this theory. In addition, decreased cerebral blood flow, environmental toxins and a decrease in acetylcholine have all been labeled potential culprits. Various theories for the cause of Alzheimer’s have been put forth but as yet none have been shown true.

Certain qualities are consistently observed in the Alzheimer’s victim. These dysfunction’s, though, are not exclusive to Alzheimer’s disease. Consequently, declaring Alzheimer’s by these parameters is a matter of degree rather than an absolute. Characteristic dysfunction’s have been noted in Alzheimer’s victims, but the degree and severity of these varies from patient to patient. Thus, evaluation of the patient’s mental status must be made based on the sum, rather than a single characteristic. Memory is one of the first noticed deficiencies, beginning typically with the recent and short term memory, and progressing from there as the disease grows more severe. In addition, deterioration in language skills, attention span, praxis (performance of an action), and visuospatial skills are commonly seen. Also observed are changes in the actions and personality of the Alzheimer’s victim. These include changes in mood, motor activities, activities of daily living, socialization skills, psychotic disturbances, vegetative symptomology, and rise in anxiety levels. Again, the presence of these symptoms by themselves does not define a patient’s condition as Alzheimer’s disease, only serving to point to an Alzheimer’s-like dementia.

Neuroanatomically and neurohistologically, the picture of Alzheimer’s is no more simple. In all cases postmortem autopsy reveals cerebral cortical atrophy, senile plaques, neurofibrillar tangles and granulovacuolar changes. These are known as the hallmarks of the Alzheimer’s brain. Again, these are not exclusive to Alzheimer’s, but may be found in various other pathologies and the normal aging brain. With Alzheimer’s disease, cell loss, plaques, and neurofibrillary tangles have been noted in the frontal and temporal lobes, hippocampus, amygdala, and the basal ganglia with high frequency, but degeneration is also sometimes noted in various other locations of the brain. One of the more recent theories, suggests that the reason that the observed cell loss is so important is that the cells lost are projection neurons. Hence, loss of these neurons will cause loss of connection between brain structures, thus blacking out these centers much in the same way as cutting a powerline can black out an entire neighborhood. In attempting to isolate the underlying cause or an effective treatment, much research today is geared into isolating deficiencies, conditions, or alterations that occur that lead to the development of Alzheimer’s. For neurotransmitter studies, the brains must be removed shortly after death, preferably within an hour postmortem for good data. Studies have shown that Alzheimer’s victims regularly demonstrate decreases in acetylcholine and somatostatin, and may exhibit decreases in norepinephrine, serotonin, and substance P as central nervous system neurotransmitters. Interestingly, neither vasoactive intestinal polypeptide nor cholecystokinin are reduced in the CNS. Other studies are looking into certain metals as possible causative agents. Additional studies are examining the plaques to try to understand their relationship with the disease. Today, research into the Alzheimer’s brain is still in it’s childhood, with research results often conflicting. A breakthrough, however, into what is really going on in the brain, could propel the disease’s study, diagnosis, and even treatment quickly forward.

As medical professionals for the baby-boomers, we are likely to witness Alzheimer’s Disease become even more of a household topic than it already is unless a preventative cure or treatment is found. As research continues, what defines Alzheimer’s will become more refined. It may even prove that Alzheimer’s is merely a class of disorders with a common outcome. It is hard to imagine in the years to come, that the cause or causes, as well as the presentation and progression of Alzheimer’s will not be elucidated. If, however, a treatment or cure is not found for this disorder, then within our lifetime, Alzheimer’s will likely force changes in society as great, if not greater than those we have and shall see due to AIDS; for unlike AIDS this is unpreventable, and with the aging population, hard decisions will follow. Issues of euthanasia, nursing home care, the ethics of treatment and treating will likely become the overshadowing topics of health care in the future.

Note: The paper that Dr. Anderson handed out on Alzheimer’s is an excellent paper

BIBLIOGRAPHY:

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