St Vitus's Dance
ST VITUS'S DANCE,  or CHOREA, a disorder of the nervous system occurring for the most part in children, and characterized mainly by involuntary jerking movements of the muscles throughout almost the entire body (see NEUROPATHOLOGY). Among the predisposing causes age is important, chorea being essentially an ailment of childhood and particularly during the period of the second dentition between the ages of nine and twelve. It is not often seen in very young children nor after puberty; but there are many exceptions. It is twice as frequent with girls as with boys. Hereditary predisposition to nervous troubles is apt to find expression in this malady, especially if the general health becomes lowered. Of exciting causes strong emotions, such as fright, ill-usage or hardship of any kind, insufficient feeding, overwork or anxiety, are among the most common; while, again, some distant source of irritation, such as teething or intestinal worms, appears capable of giving rise to an attack. It is an occasional but rare complication of pregnancy. The connexion of chorea with rheumatism is now universally recognized, and is shown not merely by its frequent occurrence before, after or during the course of attacks of rheumatic fever in young persons, but even independently of this by the liability of the heart to suffer in a similar way in the two diseases. Poynton and Paine have demonstrated a diplococcus, which they regard as the specific micro-organism of rheumatism, and which has been found in the lymph spaces in the cortex in chorea. An attempt has recently been made to demonstrate the infectious nature of the chorea.
The symptoms of St Vitus's dance sometimes develop suddenly as the result of fright, but much more frequently they come on insidiously. They are usually preceded by changes in disposition, the child becoming sad, irritable and emotional, while at the same time the general health is somewhat impaired. The first thing indicative of the disease is a certain awkwardness or fidgetiness of manner together with restlessness. In walking, too, slight dragging of one limb may be noticed. The convulsive muscular movements usually first show themselves in one part, such as an arm or a leg, and in some instances they may remain localized to that limited extent, while in all cases there is a tendency for the disorderly symptoms to be more marked on one side than on the other. When fully developed the phenomena of the disease are very characteristic. The child when standing or sitting is never still, but is constantly changing the position of the body or limbs or the facial expression in consequence of the sudden and incoordinate action of muscles or groups of them. These symptoms are aggravated when purposive movements are attempted or when the child is watched. Speech is affected both from the incoordinate movements of the tongue and from phonation sometimes taking place during an act of inspiration. The taking of food becomes a matter of difficulty, since much of it is lost in the attempts to convey it to the mouth, while swallowing is also interfered with owing to the irregular action of the pharyngeal muscles. When the tongue is protruded it comes out in a jerky manner and is immediately withdrawn, the jaws at the same time closing suddenly and sometimes with considerable force. In locomotion the muscles of the limbs act incoordinately and there is a marked alteration of the gait, which is now halting and now leaping, and the child may be tripped by one limb being suddenly jerked in front of the other. In short, the whole muscular system is deranged in its operations, and the term " insanity of the muscles " not inaptly expresses the condition, for they no longer act in harmony or with purpose, but seem, as Trousseau expresses it, each to have a will of its own. The muscles of organic life (involuntary muscles) appear scarcely,  This name was originally employed in connexion with those remarkable epidemic outbursts of combined mental and physical excitement which for a time prevailed among the inhabitants of some parts of Germany in the middle ages. It is stated that sufferers from this dancing mania were wont to resort to the chapels of St Vitus (more than one in Swabia), the saint being believed to possess the power of curing them. The transference of the name to the disease now under consideration was a manifest error, but so closely has the association now become that the original application of the term has been comparatively obscured.
if at all, affected in this disease, as, for example, the heart, the rhythmic movements of which are not as a rule impaired. But the heart may suffer in other ways, especially from inflammatory conditions similar to those which attend upon rheumatism and which frequently lay the foundation of permanent heart-disease. In severe cases of St Vitus's dance the child comes to present a distressing appearance, and the physical health declines. Usually, however, there is a remission of the symptoms during sleep. The mental condition of the patient is more or less affected, as shown in emotional tendencies, irritability and a somewhat fatuous expression and bearing, but this change is in general of transient character and ceases with convalescence.
This disease occasionally assumes a very acute and aggravated form, in which the disorderly movements are so violent as to render the patient liable to be injured, and to necessitate forcible control of the limbs, or the employment of anaesthetics to produce unconsciousness. Such cases are of very grave character, if, as is common, they are accompanied with sleeplessness, and they may prove rapidly fatal by exhaustion. In the great majority of cases, however, complete recovery is to be anticipated sooner or later, the symptoms usually continuing for from one to two months, or even sometimes much longer.
The remedies proposed have been innumerable, but it is doubtful whether any of them has much control over the disease, which under suitable hygienic conditions tends to recover of itself. These conditions, however, are all-important, and embrace the proper feeding of the child with nutritious light diet, the absence of all sources of excitement and annoyance, and the rectification of any causes of irritation and of irregularities in the general health. For a time, and especially if the symptoms are severe, confinement to the house or even to bed may be necessary, but as soon as possible the child should be taken out into the open air and gently exercised by walking. Ruhrah, recognizing the importance of rest, recommends a modified Weir-Mitchell treatment. Of medicinal remedies the mst serviceable appear to be zinc, arsenic and iron, especially the last two, which act as tonics to the system and improve the condition of the blood. In view of the connexion of chorea with rheumatism, Koplik and Dr D. B. Lees recommend saiicylate of soda in large doses. Recently ergot, hot packs and monobromate of camphor have found advocates, while cessation of the movements has followed the application of an ether spray to the spine twice daily. As sedatives in cases of sleeplessness, bromide of potassium and chloral are of use. In long-continued cases of the disease much benefit will be obtained by a change of air as well as by the employment of moderate gymnastic exercises. The employment of massage and of electricity is also likely to be beneficial. After recovery the general health of the child should for a long time receive attention, and care should be taken to guard against excitement, excessive study or any exhausting condition, physical or mental, from the fact that the disease is apt to recur, and that other nervous disorders still more serious may be developed from it.
In theTare instances of the acute form of this malady, where the convulsive movements are unceasing and violent, the only measures available are the use of chloral or chloroform inhalation to produce insensibility and muscular relaxation, but the effect is only palliative.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)