SYNONYMS.—Myalgia rheumatica or myopathia; Fr. Rheumatisme musculaire; Ger. Muskelrheumatismus.
DEFINITION.—The affections included under this term are certain painful disorders of fibro-muscular structures. They are commonly found in persons the subjects of the rheumatic diathesis, and are characterized by pain and often spasm, and sometimes a slight degree of fever. No doubt as our knowledge increases so many attacks connected with painful states of muscles and fasciæ are eliminated from the somewhat uncertain group of muscular rheumatism. True inflammation is not believed to exist, and pathological investigation has rarely shown any morbid changes in the affected parts. The symptoms, therefore, have been attributed to some temporary hyperæmia, slight serous exudation, or neuralgic state of the sensory nerve-filaments. The strongest support is given to this statement from the absence of any marked tenderness in such affected muscles as can be sufficiently examined. In certain cases, undistinguishable clinically, it is quite probable that a periarthritis is in reality the principal factor in the case. In others, again, a subacute rheumatism affecting a joint seems to spread to the adjoining tendinous sheaths, and thus secondarily to attack the muscles themselves, the affection of which may ultimately remain the only condition present.
ETIOLOGY.—Muscular rheumatism is a very common affection. All ages are liable to its occurrence, but the part affected varies with the time of life, children and young adults being much more subject to torticollis, and older persons to lumbago and general rheumatism of the limbs. Amongst hospital patients the disease prevails more amongst men than women, owing doubtless to the greater exposure of the former to the cold; but amongst other classes the same difference is not seen. It is observed in all countries, but according to some writers it is unusually frequent in tropical climates, although there acute rheumatism is very uncommon. The causes of muscular rheumatism are mainly exposure to cold and strain or fatigue of muscles. If these two conditions coexist—e.g. standing in a draught of cold air or lying on the ground when fatigued—the chances of the affection coming are greatly enhanced. Strain, a twist of the body, or a false step can actively start an attack of this kind, and by the sufferers themselves it is constantly attributed to this cause. The part played by this element is difficult to determine, a very slight strain being often followed by great pain and distress from the subsequent rheumatic affection. Some individuals are specially prone to attacks, the slightest current of air, change of clothing, etc. being sufficient to determine its occurrence. These persons are often found to have suffered from rheumatism in some other form, and thus in them we must consider that the rheumatic diathesis furnishes the reason for their unusual susceptibility. It only remains to mention the fact that a disposition to gout seems to favor the development of muscular rheumatism. In gouty families, therefore, it has been observed to be common.
SYMPTOMS.—In all cases pain is the prominent, and in many cases the only, symptom present. In all except the more aggravated attacks pain is felt only when the affected part is disturbed. In such when complete rest or fixed immobility is maintained there is comfort, or at most a somewhat dull, uneasy sensation, but when any contraction of the muscles in question is produced, whether voluntary or otherwise, severe often excruciating pain is at once experienced, often giving rise to a sudden cry or causing the features to be contracted in a grimace. The suffering ceases almost at once when the muscular contraction is relaxed. In more aggravated attacks the pain is more severe, and besides persists, though to a less degree, even when there is no contraction. In rare cases when the maximum degree has been attained there is continuous pain, but the affected muscles are persistently maintained in a relaxed condition by means of true spasm in the surrounding muscles. Slow passive movement affects the subject of muscular rheumatism, and may often be accomplished with a little management without causing pain. If, at the same time, these muscles be handled by pinching and slight pressure, it will be found that they are very sensitive to the touch. When some tenderness does exist, it is slight and is not located in the district of the lower nerve-trunks. Pressure even sometimes allays pain. The constant effort to avoid pain gives rise to a feeling and appearance of stiffness, and thus characteristic attitudes and positions of the head, trunk, or limbs are voluntarily and persistently maintained. There is no spasm of the affected muscles; the distortion is the result of stiff contraction of the associated muscles, which thus forcibly fix the faulty one and hold it in a state of relaxation. Cramp or spasmodic contraction of a single muscle of a painful character does, however, sometimes occur in rheumatic subjects, and much resembles the condition above described. In the same persons also muscular rheumatism may occur in a much more fugitive or erratic form, frequently being nothing more than a slightly painful condition of some group of muscles which have in some way been exposed to cold. This may last but a short time, and either spontaneously disappear or be readily removed by exercise or friction. Muscular rheumatism is generally confined to one muscle or a single group of muscles. Those most liable to it are the very superficial and those easily exposed to cold (e.g. the deltoid and trapezius), powerful muscles often subjected to violent strain (e.g. the lumbar muscles), and those aiding in the formation of the parietes of the great cavities.
This affection very commonly exists without any constitutional disturbances, but sometimes there are present the symptoms of pyrexia—slight elevation of temperature and temporary disorder of the digestive organs—loss of appetite, constipation, and general malaise.
The acute forms generally last but a few days, terminating by gradual subsidence and final disappearance of the pain. The fugitive kind, already alluded to, may, however, be present more or less during several weeks.
DIAGNOSIS.—Errors of diagnosis between muscular rheumatism and a variety of other disorders are common. Laymen especially are only too apt to attribute pain felt in muscles at once to rheumatism of these muscles—a term which is badly abused. Some of these errors are of no great interest, but others are of the highest importance, for they may cause the onset of a serious disease to be overlooked. The principal affections to be borne in mind with reference to diagnosis are the following: organic diseases of the spinal cord (notably tabes dorsalis), causing peripheral pains as an early symptom; functional disorder of the same part, as hysteria or spinal irritation; intra-thoracic inflammation; the onset of an exanthem; the pains produced by the chronic poisoning of lead and mercury; neuralgia; painful spasm of muscle from deep-seated inflammation or suppuration. It is sufficient to indicate these various sources of fallacy, which, if remembered, can generally be guarded against by a consideration of the special features characteristic of each one.
TREATMENT.—The indications for the treatment are mainly two—viz. to relieve the pain and to counteract the diathetic condition generally present. The relief of the pain is accomplished in various ways, according to the seat of the trouble. In severe cases it is proper to resort to the hypodermic use of morphia, to which may be advantageously added some atropia. When the pain is seated in large muscles, the injection will produce better results if thrown not merely under the skin, but into the substance of the muscle. Sometimes perfect rest in bed is necessary to secure the required immobility; in other cases this can better be secured by plaster or firm bandages. Soothing anodynes are extremely useful locally, and counter-irritants also may be used with benefit. Liniments give us a convenient form of application. The best are those containing a considerable proportion of chloroform with either aconite or belladonna, or both. The repeated application of tincture of iodine often gives great relief. Galvanism sometimes proves a rapid cure. Continuous heat is nearly always grateful, and may be applied either in the dry form or by means of soft warm linseed poultices with or without a percentage of mustard. When these are discontinued, care should be taken to protect the affected muscles from cold by keeping them enveloped in flannel or woollen coverings.
Whilst these local measures are being adopted the constitutional disorder should also receive attention. A diaphoretic action should be set up. For this purpose the hot-air or Turkish bath at the outset would seem to be sometimes really abortive. Of medicinal means amongst the most reliable are liquor ammonii acetatis and Dover's powder. Pilocarpine occasionally proves useful. The fixed alkaline salts are also sometimes beneficial, such as the acetate and citrate of potassium and, at a later stage, the iodide of potassium. In a certain number of cases of muscular rheumatism the sodium salicylate acts promptly and well. This drug will succeed well in proportion as the evidence of the rheumatic constitution is well marked, as shown by the tendency on other occasions to attacks of acute articular rheumatism.
Persons who are subject to muscular rheumatism should be made to wear warm clothing, avoid draughts, guard against strains and twists, and in other respects to be careful of their general hygiene. Obstinately recurring cases will very often receive benefit from a visit to some of the natural springs known to possess antirheumatic qualities.