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| Alzheimer's Disease |
| Etiology •Familial types are known but most cases are sporadic. |
| Pathogenesis •The cause of Alzheimer's disease is unknown. •May be due to deposition of amyloid in the parenchyma of the brain which is toxic to neurons and oligodendroglia. •An alternative hypothesis is that deposition of amyloid is a secondary effect. The amyloid deposition is thought to be due to an abnormality in the amyloid precursor protein., |
| Epidemiology •Senile dementia is seen in over 32% of the population over 85 years and increases rapidly after that. •Alzheimer's disease is the most common senile dementia in patients greater than 65 years old. Alzheimer's disease is seen before 65 years of age and is called presenile dementia. Most familial cases are presenile. •Since the 85 years of age and older group is increasing rapidly, Alzheimer' disease is becoming an important disease. |
| General Gross Description •Generally atrophied with large ventricles. |
| General Microscopic Description •Alzheimer's disease is characterized by the formation of round senile plaques often with an amyloid center in the neuropil of the cerebral cortex as well as neurofibrillary tangles within neurons. •The diagnosis is made by counting the number of senile plaques per 20x field and the number of neurofibrillary tangles in the same area, using the Bielschowsky stain. |
| Clinical Correlation •Alzheimer's disease is a devastating disease causing loss of recent memory, followed by old memories and apraxias or inability to carry out a normal procedure such as dressing, eating etc. The patient is finally bedridden with many neurological signs and usually dies of pneumonia, heart attack, or stroke. •Lifespan with the disease is usually 5 Years after diagnosis but may be 10 years if the patient is otherwise healthy. Toward the end the patient is unable to recognize anyone and may become hostile. |
| References • Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp.142. • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1329-1331. |
| Alzheimer's Disease |
| Synopsis by: M. L. Grunnet M.D. (TX2000D85430)[356] |
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