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| Parkinson's Disease | ||
| Etiology •Unknown | ||
| Pathogenesis •A disease of the nigrostriatal dopaminergic system, with destruction of the melanin bearing neurons of the substantia nigra in the midbrain and the locus ceruleus in the pons. •There is a consequent decrease in dopamine levels in the caudate nucleus and putamen. •Parkinson's Disease is also called "Idiopathic Parkinson's Disease" to distinguish it from other entities which also damage the nigrostriatal system, causing a similar clinical syndrome. •Postencephalitic Parkinsonism was due to destruction of the substantia nigra in cases of Von Economo's encephalitis following World War I. •Drug users of meperidine derivatives have been similarly affected by a contaminant, MPTP., | ||
| Epidemiology •A common disease of middle and old age, with onset from age 50 to 70 years. •More common in males, especially when onset is before age 50. | ||
| General Gross Description •The classical gross finding is a marked decrease or loss of the black pigmentation of the substantia nigra. •Otherwise, the brain as a whole appears unremarkable. •Examples: | ||
| General Microscopic Description •There are a decreased number of melanin bearing neurons in the substantia nigra and locus ceruleus, with extravasated pigment from dead neurons, and gliosis. •An eosinophilic discrete round intracytoplasmic inclusion called the "Lewy body" is characteristically found in viable appearing neurons. •The Lewy body by EM is made of fine filaments. It contains neurofilament and ubiquetin antigens. Immunohistochemical markers for ubiquitin enable the easy identification of Lewy bodies in microscopic sections. •Lewy bodies are not found in cases of postencephalitic Parkinsonism, or in MPTP intoxication. •Examples: | ||
| References • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 1332-1333. • Harrison's Principles of Internal Medicine, 13th Ed: Isselbach et. al. (eds). New York, McGraw-Hill, 1994, pp. 2275-2278. This link will directly take you to the relevant new literature Parkinson's Disease
| Synopsis by: J. Hasson, MD (TX2000D84500)[610]
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