CHAPTER I.

MYALGIA.

Of all the diseases which superficially resemble neuralgia, none are so likely to be confounded with it, on a cursory glance, as myalgia. More careful inquiry, however, furnishes, in nearly all cases, ample means for distinguishing between the two affections.

Myalgia is an exceedingly painful affection, and it is also much more common than was formerly supposed. It is to Dr. Inman that we undoubtedly owe the demonstration of the frequent occurrence of this malady, and the facility with which it may be mistaken for other, and sometimes much more serious, diseases, with very disastrous results. At the same time, I must express the opinion that this ingenious author has decidedly exaggerated the importance of this local disease at the expense of an unjust depreciation of the frequency and significance of other painful disorders which have their origin within the nervous system.

Myalgia proper includes all those affections which are severally known as "muscular rheumatism" (for the muscles generally), and "lumbago," "pleurodynia," etc. (according to locality). It is essentially pain produced in a muscle obliged to work when its structure is imperfectly nourished or impaired by disease.

The clinical history of the different varieties of myalgia absolutely requires this key for its interpretation; otherwise, the appearance of the sufferers from different kinds of myalgia is so widely dissimilar that we should be exceedingly likely to miss the important features of treatment, which must be applied to them all in common. Nothing, for instance, can be more strikingly unlike than the appearance of the pallid, stunted, under-nourishment cobbler who complains of epigastric myalgia, and that of the ruddy and muscular navvy who suffers from acute lumbago, or the similarly plethoric-looking country commercial traveller, who has been driving in his gig against wind and rain, and complains of violent aching pains in one or both shoulders; yet one and all of these individuals are suffering from precisely the same cause of pain, viz., a temporarily crippled muscle or set of muscles which has been compelled to work against the grain. Why this state of things should invariably be interpreted as sensation in the form of acute pain never absent, but severely aggravated by every movement of the affected part, is a matter beyond our powers of explanation, we must accept it as an ultimate fact for the present.

There is scarcely any need to describe the pain of myalgia, since almost every one has suffered either from lumbago, or from a stiff neck produced by cold. The pain is essentially the same in all cases; it is an aching actually felt either in or toward the tendinous insertions of the affected muscles, and sharply renewed by every attempted contraction of those muscles. The variations in the character and severity of the pains are really entirely due to the greater or the less opportunity for physiological rest which the muscle can obtain. Thus the most obstinate and the most severe, kind of myalgic pain is undoubtedly that of pleurodynia--pain in the intercostal muscles and their fibrous aponeuroses--a fact which depends on the incessant movements which these muscles are compelled to perform in the act of respiration. And next to this in severity and obstinacy are myalgias of the great muscles which are incessantly engaged in maintaining, by their accurately opposed contraction, the erect position of the spinal column and of the head. This rate of proportional frequency and severity, however, must be taken as strictly relative; _i. e._, it is correct upon the supposition that the different sets of muscles were equally worked and that the state of nutrition was equal in the different parents. It is otherwise when the conditions are reversed. Thus, the unfortunate cobbler or tailor, who sits for long hours in one cramped and bent posture, is continuously exerting his recti abdominales (probably suffering from an under-nutrition common to all his tissues) to a degree perfectly abnormal, and out of all proportion to the functional work he is getting out of any other part of his muscular system. The consequence is, that he comes to us complaining of acute epigastric, and sometimes pubic, pain, rising to agony when he assumes his ordinary sitting posture, and only reduced to any thing moderate by the most complete extension of the whole trunk in the supine posture.

There is no need to dilate at greater length upon the varieties in the symptoms of myalgia, according as it affects one or another part of the body. We must consider, briefly the different kinds of cause that produce it. The immediate source of the pain being, as we have seen, the sense of embarrassment in a muscle obliged to contract when unfit for the work, we have to ask what are the remoter causes that can produce this special unfitness for the work of contraction. They are three: (_a_) Overlabor pure and simple (_i. e._, in proportion to the existing bulk and quality of the muscle); (_b_) cold, and especially damp cold, producing a semi-paralyzing effect on the vaso-motor nerves, and causing congestion and sometimes a little effusion among the fibres or within the sheath of the muscle; (_c_) fatty degeneration of muscle which is exposed to inevitable and incessant work. Either of these conditions may so disable the muscle that its unavoidable contractions will set up the myalgic state.

Undoubtedly however there is something further, in the shape of a natural predisposition not yet understood, which makes some patients so much more liable to suffer myalgic pain as a consequence of this sort of influences than other persons are. I am in no condition to decide what the nature of this predisposition is; I feel sure it is heightened by an inherited or acquired gouty taint, but I have seen it in people whom there is no reason to suspect of gouty tendencies. It appears to have no connection with true rheumatism.

Still after all that can be said, myalgia remains a disease chiefly of local origin, and depending for nine-tenths of its causation upon a derangement between the balance of work and nutrition in the muscle.

As regards the diagnosis of myalgia from neuralgia, which is a very important matter, the following are the main points that we should recollect:

_Neuralgia._ _Myalgia._

Follows the distribution of a Attacks a limited patch or recognizable nerve or nerves. patches that can be identified with the tendon or aponeurosis of a muscle which, on inquiry, will be found to have been hardly worked.

Goes along with an inherited or As often as not occurs in persons acquired nervous temperament, with no special neurotic which is obvious. tendency.

Is much less aggravated, Is inevitably, and very severely, usually, by movement than aggravated by every movement of myalgia is. the part.

Is at first accompanied by no Distinguished from the first, by local tenderness. localized tenderness on pressure as well as on movement.

Points douloureux, when Tender points correspond to established at a later stage, tendinous origins and insertions correspond to the emergence of of muscles. nerves.

Pain not materially relieved by Pain usually completely and always any change of posture. considerably relieved by full extension of the painful muscle or muscles.

The treatment of myalgia is not only satisfactory in itself, but often affords, in its results, a very desirable confirmation of diagnosis.

For a very large number of cases, all that is required is (_a_) to put and keep the affected muscle in a position of full extension, which is only to be changed at somewhat rare intervals; (_b_) to cover the skin all over and round it with spongio-piline, so as to maintain a perpetual vapor-bath; (_c_) on the subsidence of the acutest pain and tenderness, to complete the treatment by one or two Turkish baths, to be taken in the manner that I have recommended by speaking of the prophylaxis of neuralgia.

When treatment such as this cures a pain which was greatly aggravated by muscular movement, we may be sure that pain was myalgic and not neuralgic.

The pain, however, is not unfrequently rebellious to such simple remedies as these, more especially when (as in pleurodynia) we are not able to enforce complete physiological rest of the part. When this is the case, we shall find the internal use of twenty and thirty grain doses of muriate of ammonia by far the most effective remedy. In the first very acute stage of a severe case it may be advisable to inject morphia hypodermically; but this is seldom necessary. The muriate-of-ammonia treatment may be usefully accompanied by prolonged gentle frictions, three or four times a day, with a weak chloroform liniment.

When there is visibly a very great deficiency in the general nutrition, we shall often fail to obtain a cure until we have remedied this defect; and accordingly, in the majority of cases of half-starved and overworked needle-women, cobblers, tailors, and the like, who present themselves in the out-patient room, I accompany the above-named treatment with the steady administration of cod-liver oil for three or four weeks or more.

There is one remedy for this pain which I have myself seen used in only a few cases, but which I believe promises exceedingly well for the treatment of obstinate myalgia; viz., acupuncture. I have not even mentioned it as a remedy for neuralgia, for I believe it to be totally useless in true cases of that disease, whether applied in the simple form or in that of galvano-puncture. I think very differently of its use in myalgia; and I venture to believe that it is entirely to cases of this disease that the exceedingly interesting observations of Mr. T. P. Teale, in a recent number of the _Lancet_, apply. Where (after the usual remedies for myalgia have been applied) we are unable to get rid of a deep-seated and fixed muscular pain, I believe it to be excellent practice to plunge two or three long needles deeply into the muscle near its tendinous attachment.