Other parts more distant may become affected, the face becoming flushed, palpitation of the heart and profuse perspiration, either local or more or less general, ensuing, followed by exhaustion.
When there is a marked hyperæsthesia of the distal phalanges of the fingers, there may be a glossy appearance of the skin, or the parts may appear inflamed and as if about to suppurate, or there may be chilblains. A rare symptom is change in the character of the nails, which become brittle and crack off like shell, either spontaneously or when an attempt is made to cut them.
GENERAL SYMPTOMS.—Besides the various symptoms above enumerated, there may be others more general in character, such as intense headache and great general nervousness, the emotional character being generally well marked, as is shown by the disability being greatly increased when the patient knows some one is watching and criticising. There may be also vertigo and sleeplessness. When there is an associated spasm of the analogous muscles of the other arm and hand, although there is no apparent trouble in the arm which is being used, it shows that the hitherto almost automatic act is losing some of its automatism: this, although rare, is an important premonitory symptom.
A rare symptom, which, as far as my knowledge allows me to say, is confined to telegraph operators, is an inability to mentally grasp the proper number of dots and dashes composing certain Morse characters: this usually coincides with the difficulty experienced in making those characters after they have been thought of, and also makes it difficult for them to recognize them by sound even when properly made by another person. The characters composed entirely of dots seem to cause the most trouble in this way.
Electrical Reactions.—In those cases where spasm of one or more muscles is a more or less marked symptom electrical examination shows, both to the faradic and galvanic current, a quantitative increase in the reaction, both in the nerves and muscles; with the galvanic current the cathodal closing contraction is more marked than the anodal closing contraction, as in health (KaSZ > AnSZ); only this formula is most marked in the affected arm. When paresis is present there will be a quantitative decrease in the reaction, the formula still being KaSZ > AnSZ. In the same arm some muscles may show a quantitative increase and others a quantitative decrease. Where there is a neuritis present the electrical examination will show a quantitative increase, but where the disease has advanced to degeneration of the nerve the reaction of degeneration will be found, and the formula will be AnSZ > KaSZ; there is, therefore, a qualitative change, but this must be looked upon as rather uncommon in this class of diseases.
Poore44 is of the opinion that increased irritability shows an early, and decreased irritability a late, stage of the same condition. According to his tables, but very few of his 75 cases of impaired writing-power showed this quantitative increase, while every case showing the least evidence of cramp that has come under my observation has shown it in one or more muscles; in a few cases the antagonistic muscles showed a decrease. Increased sensitiveness to both currents is sometimes noticed.
44 “Writers' Cramp and Impaired Writing-power,” by C. V. Poore, M.D., Medico-Chirurgical Trans., vol. lxi, 1878.
COURSE.—The course of the disability is slow and, unless appropriate treatment is instituted, progressive, although at times there are periods during which the symptoms ameliorate without assignable cause, thus giving rise to false hopes. The usual history is that group after group of muscles becomes implicated as these are in turn used to relieve those first affected, the left arm, should this be used, becoming disabled in the same manner as the right, and the unfortunate sufferer is then compelled to give up his calling or else to lessen very materially the amount of his labor.
DURATION.—As might be inferred from what has been written, those who have suffered for years with this affection may expect it to continue for the remainder of their days; but the later investigations upon this subject give rise to much hope that in future the duration of this troublesome complaint will be materially shortened when the disease is recognized early and treatment instituted at the very first symptom.
DIFFERENTIAL DIAGNOSIS.—Although many of the cases of copodyscinesia are diagnosed with comparative ease, there are others which require much study, as there are several disorders which are apt to mislead by the similarity of symptoms.