Synonyms.—Shaking Palsy; Parkinson's Disease.
Definition.—A chronic disease of the nervous system, characterized by rhythmical contractions of the muscles of the limbs, associated with weakness and rigidity.
Etiology.—This is a disease of adult life, rarely ever occurring before forty, the largest number appearing between the ages of forty and sixty. It occurs more frequently in men than women, the ratio being about two to one. Heredity seems to bear no causal relation other than to furnish a neurotic temperament. Acute diseases, cold, fright, great emotion, worry, mental strain, and injuries have been considered as producing causes, though no definite cause is known.
Pathology.—No characteristic lesions are found, though, in all probability, the disturbance is in the cerebral cortex. Some regard the degeneration of a senile type. Certain sclerotic changes have been described in the spinal cord, starting from the neighborhood of the vessels. Nothing, however, is positively known of the nature of the lesions.
Symptoms.—Except where the result of fright, the disease generally comes on so insidiously that the patient is unable to say when the first symptom began. The first evidence is usually a slight tremor in the muscles of the fingers and hand, gradually extending to the arm and leg of the same side. The right side is the first to be affected as a rule, then both become involved. The motions of thumb, fingers, and wrist are characteristic, the forefinger sliding over the ball of the thumb, while the wrist is semi-rotated. If the head be involved, there is a constant nodding motion. The tremors are usually suspended during voluntary motion, at once to resume when such action ceases. The tremors are constant during waking hours, save in the exception just noted. During sleep there is a suspension of the tremblings.
It is noticed as the disease progresses, that voluntary movements are slow and awkward, the muscles appearing stiff, another characteristic of the lesion.
The attitude and gait of the patient is most striking. The head is thrown excessively forward, the eyes straight away or slightly elevated, and the face passive. In walking, the patient takes very short steps, and trots along, hurrying one foot after the other, seemingly to prevent pitching forward. The knees are apt to touch or rub, while the feet may be slightly everted, or they may cross.
The muscles show no evidence of atrophy or trophic changes, even in the advanced stages. The electrical irritability of the muscles is retained, and the reflexes remain normal. The bladder and rectum are usually unimpaired.
The facial expression of victims of "shaking palsy" is also characteristic, and, because of so little play of the features, is as though the patient wore a mask. In some cases the mouth is kept open, the saliva dropping constantly from the mouth. The speech is usually slow, monotonous, and the voice tremulous and high-pitched.
Diagnosis.—The symptoms are so characteristic that one can scarcely be mistaken in the diagnosis. We recognize it from multiple sclerosis in that the tremors are not increased by voluntary movements, that it usually begins in the upper extremities, that there is no oscillation of the eyeballs, and that there are no sensory disturbances. From chorea, by the marked regularity of the tremors, from four to six per second, by their persistency even during sleep, and that the tremulous condition of the muscles is not increased by voluntary movements.
Prognosis.—The disease is incurable, though there is no immediate danger to life, the patient living for years. There may occasionally be intermissions of the tremors, though generally there is a slow advance in the disease. Death usually occurs from some intercurrent disease.
Treatment.—Fowler's solution, hyoscyamus, and phosphid of zinc have each had their advocates as beneficial remedies in this disease, though their influence is questionable. The patient should avoid, as far as possible, all mental excitement and excessive fatigue of the muscles. The diet should be as nourishing as possible, though one that is easily digested, and the general health improved when impaired.