57

CASE 57


A 66-year-old man presented to his physician with complaints of hand tremors and stiffness of movement. During the history, the patient revealed that he had difficulty walking, getting out of his chair, and swallowing. He also stated that he started drooling about a month ago. The physician noted that the patient answered his questions in a whispering, rapid speech pattern. The physical examination showed that the patient had pill-rolling bilateral hand tremor at rest that diminished with voluntary movement, muscle rigidity with a series of brief muscle relaxations (cog-wheel rigidity), and bradykinesia. A minor degree of postural instability was observed as the patient slightly stumbled forward during ambulation and maintained a stooped-forward posture. The patient was diagnosed with Parkinson’s disease and was treated with L-DOPA.



WHAT STRUCTURE OF THE BRAIN, WHEN DAMAGED, PRODUCES THE SYMPTOMS OF PARKINSON’S DISEASE?


Parkinson’s disease is a lesion of the basal ganglia characterized by a loss of dopaminergic neurons in the substantia nigra, a bilateral nucleus that extends through the length of the midbrain (Fig. 7-26A). The neurons, which project to the corpus striatum (composed of the caudate nucleus, putamen, and globus pallidus), are responsible for inhibiting movements. Loss of this inhibition through the degeneration of the neurons in the substantia nigra permits movements that the patient does not want to perform but cannot prevent.


image

FIGURE 7-26 Parkinson’s disease. A, Normal black-staining substantia nigra. B, Substantia nigra is depigmented. C, Bright eosinophilic Lewy bodies in a neuron of the substantia nigra.


(Kumar V, Abbas A and Fausto N: Robbins & Cotran Pathologic Basis of Disease, 7e

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Jun 16, 2016 | Posted by in ANATOMY | Comments Off on 57

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