Parkinsonism (redirected from Parkinsonian disorders)

Parkinsonism: see Parkinson's disease.

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parkinsonism

Neurological disorder causing progressive loss of control of movement. It was first described in 1817 by British physician James Parkinson (1755–1824). The cause of primary parkinsonism, or Parkinson disease, is unknown. The mean age of onset is about 57, but juvenile parkinsonism is also known. Neurons in the brain that normally produce dopamine deteriorate. When 60–80% are destroyed, signals suppressing unintended movement are disrupted and symptoms appear, including tremor at rest, muscle rigidity, trouble in starting movements, and loss of balance. Known causes include sleeping sickness; certain poisons; repeated blows to the head, as in boxing; and the drug MPTP. Environmental toxins or genetic susceptibility may account for some cases. Drug therapy requires careful scheduling and combinations to delay development of tolerance and side effects. Surgical pallidotomy (destruction of the globus pallidus, a brain structure involved in motor control) and transplantation of fetal dopamine-producing tissue remain experimental.

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parkinsonism [′pär·kən·sə‚niz·əm]

(medicine)

A clinical state characterized by tremor at a rate of three to eight tremors per second, with “pill-rolling” movements of the thumb common, muscular rigidity, dyskinesia, hypokinesia, and reduction in number of spontaneous and autonomic movements; produces a masked facies, disturbances of posture, gait, balance, speech, swallowing, and muscular strength. Also known as paralysis agitans; Parkinson's disease.

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Parkinsonism 

(also Parkinson’s disease), a chronic progressive disease of the central nervous system characterized by motor disorders. First described in 1817 by the English physician J. Parkinson under the name “shaking palsy,” it is one of the most common neurological diseases, primarily of older people. Its causes are diverse and include encephalitides, cerebral atherosclerosis, head injury, and poisoning by barbiturates or carbon monoxide. The cause cannot be determined in almost half the cases.

In parkinsonism, there is a deficiency of dopamine, a product of catecholamine metabolism, in the subcortical structures of the brain, which results in disruption of the balance between the main systems of brain transmitter substances and in lack of control of movements. Morphological study of the brains of those afflicted reveals destruction of substantia negra cells in the subcortical structures. The principal symptoms are a constant tremor of arms and legs, a masklike facial expression, salivation, increased tonus of all the muscles and general rigidity, and slowness of movements, in particular, a slow gait with small steps.

Treatment with L-dopa, which normalizes the concentration of dopamine, is effective but causes side effects in some patients. Central-acting cholinolytics are used in the initial stages. Surgery is indicated if drug therapy is ineffective. Brain surgery is performed by the stereotaxic technique, which involves destruction of a small area in the subcortical structures. It is quite safe and usually relieves all symptoms of parkinsonism for many years.

REFERENCES

Kandel’, E. I. Parkinsonizm i ego khirurgicheskoe lechenie. Moscow, 1965. (Bibliography.)
Cooper, J. Parkinsonism: Its Medical and Surgical Therapy. Springfield, Ill., 1961.

E. I. KANDEL’