– A slowly progressive, degenerative neurologic disorder characterized by slow, impoverished movement; muscle rigidity; resting tremor; and postural instability.
Causes and Incidence
Primary parkinsonism is idiopathic, whereas secondary forms of the disease can be caused by drugs (neuroleptics, reserpine, metoclopramide, tetrabenazine, N-MPTP [a byproduct of heroin synthesis]); toxins (carbon monoxide, carbon disulfide, manganese); structural lesions of the midbrain or basal ganglia; vascular lesions of the striatum from repeated head trauma; and in rare cases encephalitis. Parkinsonism is the fourth most common neurodegenerative disease of the elderly. It affects about 1% of those over 65 in the United States, and an estimated 40,000 cases are diagnosed each year. Men and women are equally affected; the mean age of onset is 57 years, and peak onset is in the seventh decade.
Some agent or event triggers a degeneration and loss of pigmented neurons in the substantia nigra, locus ceruleus, and other brainstem dopaminergic cell groups. The loss of these neurons leads to a depletion in neurotransmitter dopamine and interferes with the motor production of the basal ganglia. Interneuronal inclusion bodies (Lewy bodies) are left in surviving pigmented neurons and serve as biologic markers of the disease. Clinical manifestations emerge only after 75% to 80% of the dopamine innervation has been destroyed.
Infrequent blinking; lack of facial expression; deliberateness of speech; impaired postural reflexes, particularly in the arm; resting pill-rolling tremor of one hand that is absent during sleep
Progressive rigidity, slowness and poverty of movement, difficulty initiating movement; muscle aches and fatigue; masklike, openmouthed facial expression; stooped posture; gait begins slow and shuffling and quickens to a run with a forward lean; hypophonic speech with stuttering dysarthria; drooling; dysphagia; forgetfulness; resting tremors of lips, jaw, tongue, and limbs; depression
Severe postural instability; urinary retention; orthostatic hypotension; paranoia with visual hallucinations; delirium; dementia
Injury from falls is a common threat. Other complications include aspiration pneumonia, drug reactions, and disuse syndrome.
The diagnosis is based primarily on the pattern of clinical manifestations and must be distinguished from individuals with essential tremor in which the tremor is action related and without facial or gait involvement.
Stereotactic thalamotomy to alleviate tremors and rigidity in drug-resistant individuals.
Antiparkinsonian agents such as levodopa, Sinemet, Artane, Cogentin, Parsidol, and Parlodel to reduce tremor and rigidity; antihistamines and anticholinergics to extend the effects of levodopa; antidepressants for depression; anticholinergics with neuroleptics to prevent parkinsonism.
Long-term physical therapy to maintain muscle tone, function, and range of motion, gait training, and transfer training; occupational therapy to maintain activities of daily living and teach safety skills; speech therapy to evaluate and improve swallowing abilities, reduce dysarthria, and strengthen facial muscles; warm baths and massage to relax muscles; consistent exercise program; assistive devices (canes, walkers, wheelchairs, electric lift chairs, grab bars, raised toilet seats, bath seats, eating and hygiene devices); counseling for depression and long-term adaptation; measures to prevent skin breakdown, urinary tract infections, falls, and corneal abrasions; deep breathing to maintain vital capacity; balanced, low-protein diet; bowel and bladder programs; treatment of underlying cause in secondary parkinsonism.