A system of practical medicine. By American authors. Vol. 4

by Unknown

MYALGIA.

BY JAMES C. WILSON, M.D.

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DEFINITION.—An affection of the voluntary muscles, of which the chief, and often the only, symptom is pain on movement.

SYNONYMS.—Myalgia as a general term has few synonyms. It is sometimes called myodynia. This affection has no essential relation to rheumatism or the rheumatic diathesis; therefore the common use of the term muscular rheumatism as a synonym for myalgia is an error. This error has occasioned much confusion of thought and mistaken medication, and tends to maintain the obscurity which overhangs the subject of the so-called and often miscalled rheumatic affections in general. That true rheumatic processes may extend from serous or fibrous structures to contiguous muscular masses has, in the absence of demonstration, been assumed by many writers of authority, but that acute or subacute rheumatism, with its recognized characters, ever manifests itself primarily or exclusively as an inflammation of muscle-substance is an assumption wholly without clinical or pathological support.

The term myo-rheumatism is as inapplicable as muscular rheumatism, and lacks the sanction of usage. Myositis is a term used to describe (1) an acute inflammation of muscle, often traumatic, and commonly attended by suppuration, and (2) a chronic indurating inflammatory process, not infrequently due to syphilis. Neither of these conditions resembles the affection under consideration in its clinical aspects, nor is allied to it pathologically.

As manifested in particular muscles or groups of muscles myalgia has been described under the terms cephalodynia, torticollis (myalgia cervicalis), pleurodynia (m. pectoralis seu intercostalis), lumbago (m. lumbalis), dorsodynia, omodynia, scapulodynia (m. dorsalis), etc.

This affection must, in the present state of our knowledge, be classified with the diseases of nutrition in the more narrow sense. It is not a diathetic disease.

HISTORICAL CONSIDERATIONS.—To Inman¹ of Liverpool is due the credit of having first pointed out the frequency of this malady and the ease with which it may be mistaken for other and much more serious diseases—an error in diagnosis which has been followed by serious results, especially in the case of nervous and self-centred females and other hypochondriacal persons. It cannot, however, be denied that this author, carried away by his enthusiasm, exaggerated the importance of this local affection at the expense of undervaluing the frequency and significance of other painful disorders which have their origin in the nervous system. To Inman we also owe the term myalgia, which has the positive merit of embodying the idea of pain as the chief symptom of the disorder and the muscles as its seat, and the not inferior negative merit of implying no erroneous theory as to its nature and cause.

¹ Thomas Inman, M.D., Certain Painful Muscular Affections, 1856; Spinal Irritation Explained, 1858; On Myalgia, its Nature, Causes, and Treatment, 1860.

This affection is described in few even among the recent textbooks; in others it receives merely incidental mention; in the majority of them it is passed over in silence. Yet it is obvious that the descriptions of muscular rheumatism, which are rarely omitted, are based upon and refer to cases of various kinds which for the most part are not rheumatic at all, and very frequently are examples of true myalgia.

ETIOLOGY.—(A) Predisposing Influences.—Myalgia is "essentially pain produced in a muscle which is obliged to work when its structure is imperfectly nourished or impaired by disease." Hence all influences which unfavorably affect the nutrition of the muscles, all diseases which directly affect the integrity of their structure, predispose them to this affection. The defect in nutrition may be only relative to the amount of work the muscle is called upon to do, or there may be absolute malnutrition, implicating the whole body. The muscle may be impaired by a local disease which affects it alone, or it may share in morbid processes which also involve other and distant structures.

Sedentary occupations, leading as they do to poor nutrition of the muscular system from want of proper use and exercise; malnutrition from a diet deficient in amount or defective in kind, or in childhood from too rapid growth; the chronic wasting diseases; the state of convalescence from acute maladies; and, finally, degenerative diseases of the muscles themselves,—all favor the development of myalgia. Among the acute diseases which by their derangement of nutritive processes especially render those who have suffered from them liable to this painful affection of the muscles during convalescence, is acute articular rheumatism or rheumatic fever. It is this fact, taken together with the use of a misnomer, that has given rise to the view that the muscles share with the serous and fibrous structures in the lesions of that disease, and that myalgia is rheumatism of the muscles.

There is, however, over and above these defects in nutrition, an especial predisposition or idiosyncrasy, the nature of which is unknown, which renders certain individuals far more liable to suffer myalgic pain than others. This predisposition is encountered in those who have an inherited or acquired gouty habit and in those who are free from gout with perhaps equal frequency. It is not associated with a special liability to true rheumatism.

(B) Exciting Causes.—Myalgia is a local affection, and depends for its causation upon a derangement of the balance between the nutrition of the affected muscles and the work they have been called upon to do. Hence the most common exciting cause is (a) overwork pure and simple, especially overwork which brings into excessive and prolonged exercise unaccustomed muscles. Next in frequency is (b) exposure to cold, and especially to damp cold, when overheated or overfatigued. Finally (c), inevitable and incessant contractions, such as are physiological and are performed without consciousness or sensation in a healthy state of the muscles, will, in muscles that are defectively nourished or have undergone fatty, granular, or fibroid degeneration, cause more or less distinct myalgia.

As examples of myalgia due to the first of this group of causes (a) I may cite the pain in the adductors of the thighs after a hard ride when out of practice; the epigastric pain in children suffering from measles or other acute affection attended with persistent cough; and the pain of spasm, in particular that which follows tonic spasm, such as occurs from reflex causes in the calves of the legs at night and in bathers. Many of the pains of childhood, which are classed in common parlance together under the name of growing pains, are myalgic in their nature.

Examples of the second form (b) may be instanced in the pains of wry neck or lumbago, such as often occur in those who, being very tired, but otherwise healthy, fall asleep in a draught of air, or in those who, coming home at evening in cold weather, find a leaking pipe in the cellar, and stooping over to stop it, or in some other emergency of every-day life, bring into excessive use unaccustomed muscles in an atmosphere that is at once cold and damp.

Examples of the third group (c) are common enough in the flying or fixed muscular pains and soreness that occur in wasting chronic diseases and in the convalescence from acute maladies when prolonged muscular effort is too early undertaken. Certain forms of præcordial pain that occur in degenerative lesions of the muscular substance of the heart are without doubt myalgic in character, and will, when the clinical data of such conditions come to be more fully understood, be recognized as having more or less diagnostic value.

SYMPTOMATOLOGY.—The chief symptom, the one symptom that is common to all the cases, is pain. It is sometimes, especially in acute cases, constant; more frequently it is very slight or wholly absent when the patient is at rest, with the affected muscles in full extension, but it is invariably present or aggravated when the muscles are called into action. It is experienced throughout the muscular mass, but is most intense at or near the point of tendinous insertion. Its character is usually stabbing or stitch-like, but prolonged; sometimes it is acutely dragging or tearing; in others it is like the soreness felt on moving a contused or inflamed part. It is frequently in acute cases, almost always in chronic cases, accompanied by a sensation of stiffness in the affected muscles. The pain is essentially the same in all cases, variations in its character and severity being determined by the opportunities afforded the muscle for physiological rest. It is in accordance with this statement that the most obstinate, and the most severe form of myalgia is that which occurs in the intercostal muscles and their fibrous aponeuroses—pleurodynia. Here the affected muscles are constantly concerned in the movements of respiration, and have no time for physiological rest except in the intervals of those movements. Scarcely less stubborn and severe are the myalgias of the great muscular masses, of which the principal function is to maintain by their nicely-balanced and ever-varying contractions the erect position of the head and trunk. Less painful and of shorter duration are the myalgias of the limbs—less painful because prolonged intervals of absolute rest may be voluntarily secured; of shorter duration, because it is by rest that the balance of the nutrition is most speedily restored.

There is usually some degree of tenderness over the whole extent of the myalgic area, becoming more marked in the regions of tendinous insertion, to which it is, however, in many cases restricted. It is elicited upon moderately firm pressure, and is not associated with cutaneous hyperæsthesia.

Spasm is absent in the acute cases, except when the muscles are brought into use. Its occurrence has much to do with the intensity of the suffering then caused: in chronic cases a condition of tonic spasm or spastic rigidity, with more or less persistent painfulness, comes on, and finally in very chronic cases such tissue-changes take place as result in great impairment or absolute loss of contractile power, with or without atrophy.

Objective signs are absent, except that it is evident that the patient assumes by preference an attitude of repose, and that he keeps the involved structures as much at rest as possible. Pyrexia does not occur; the appetite and digestion are not impaired; acid sweats are not present; the urine shows no constant or characteristic alteration; there is no tendency to endo- or pericardial inflammation. If constitutional disturbance be present, it is trifling and due to prolonged local suffering and want of sleep. In by far the greater number of instances the patient remains in his usual health except the local malady.

Myalgia may affect the voluntary, and perhaps also the involuntary, muscles of any part of the body. Those most frequently involved are those subjected to continuous and excessive work, and at the same time liable to exposure to cold and damp. Single muscles or groups may be affected. The most common and important varieties are—

(1) Cephalodynia, manifested as a superficial headache, increased by movement of the scalp and attended by tenderness on pressure.

(2) Torticollis; wry neck, stiff neck—a very common form, involving the muscles of the neck, especially the sterno-cleido-mastoid. The affection is usually limited to one side, toward which the occiput is more or less firmly rotated and flexed. Great pain is experienced in attempting to turn the head in the opposite direction. The position is extremely constrained and awkward; the head cannot be moved in any direction without moving the whole body, and every effort at motion is accompanied by pain which calls forth involuntary grimaces.

(3) Omodynia, Scapulodynia, Dorsodynia—forms in which the muscles of the shoulders and upper part of the back are affected. They are very common, especially among laboring men.

(4) Pleurodynia, Myalgia of the Chest-walls.—The intercostals, pectorals, and serratus magnus may be involved. The pain is frequently referred to the region of the interdigitations of the serratus magnus with the external oblique. It is very often seated in the infra-axillary region, and is much more common on the left side. It is usually very severe, and is increased by all movements that bring the affected muscles into play. The focus of pain is sometimes a very limited spot, which is exquisitely tender upon pressure. Sometimes the pain alters its position from time to time. It is increased by deep inspiratory efforts and such acts as sneezing and coughing. Extreme flexion of the trunk from side to side also aggravates the pain. Pleurodynia sometimes comes on in consequence of severe and protracted cough, as in patients suffering with phthisis. It is then apt to affect both sides.

This form of myalgia simulates pleurisy, from which it is to be distinguished only by careful physical examination.

(5) Myalgia of the abdominal walls usually affects the recti muscles, and often assumes the guise of an acute, agonizing pain in the epigastric or pubic regions—occasionally so severe as to be mistaken for peritonitis. It is sometimes due to cough, especially in measles, but is more commonly met with in overworked and underfed tailors and cobblers as a result of the excessive action of the recti muscles in maintaining the bent posture assumed by such craftsmen at their toil.

(6) Lumbago, myalgia lumbalis.—The great muscular mass occupying the lumbar region is peculiarly prone to attacks of myalgia. Lumbago is very common in the middle and later periods of life. The attack is usually sudden and severe. Both sides are, as a rule, affected, but not to the same extent. There is constant pain across the loins, dull and aching, rarely absent altogether, always sharply aggravated by such movements as bring the affected muscles into play, and then becoming stabbing in character and almost unbearable in intensity. The spine is held stiffly, and the body is often bent slightly forward. Efforts to stand erect, to rise from the sitting posture, or to recover from the stooping position, such as is assumed in lacing one's shoes and the like, greatly aggravate the pain. In the more severe cases the patient cannot stir in his bed. There is usually tenderness upon pressure, and palpation often discovers a distinct sense of abnormal tension and resistance in the muscles.

(7) The aching, dragging pain in the back of the neck common in poorly-nourished, nervous women and in other cases of neurasthenia, the so-called pain of nervous exhaustion, is myalgia. It is felt chiefly during fatigue, is present in the erect posture, and is almost always relieved when the patient lies down. It is referred sometimes to the base of the skull, sometimes to the whole of the back of the neck, but more commonly to the spinal region just above the level of the upper borders of the scapula, and constitutes a harassing symptom of the cases in which it occurs. In this connection it must be pointed out that many of the pains of that obscure condition to which the term spinal irritation has been vaguely applied are myalgic.

Myalgia manifests itself furthermore in the limbs, in the diaphragm, and occasionally in the muscles of the eyeballs.

The COURSE of the attack is in the simpler forms acute and transient; it frequently, however, becomes chronic, and not uncommonly presents the characters of the chronic form from the beginning. Again, it sometimes attacks in succession several muscles or groups of muscles, and in by far the greater number of individuals it shows a tendency to recur from time to time.

DURATION.—The duration of acute attacks is usually brief, lasting from a few hours to several days; that of the chronic form is indefinite, tending to last years, sometimes, under unfavorable circumstances, a lifetime, with varying periods of exacerbation and remission, which are, after the disease is fully established, much influenced by the phases of the weather.

The TERMINATION of acute myalgia is commonly in full recovery, but the tendency to subsequent attacks is to be borne in mind, and guarded against by the exercise of wholesome precautions in the matter of hygiene. Neglected cases of chronic myalgia not rarely terminate in permanent alterations of the muscular structure, with loss of contractile power and rigidity, with or without atrophy.

COMPLICATIONS.—In the acute forms there are no complications, properly so called. In the more severe cases of the chronic form there is danger of nutritive changes in the tissues entering into the formation of joints, and loss of function from want of use.

SEQUELS.—There are no sequels other than those just pointed out.

PATHOLOGY AND MORBID ANATOMY.—As indicated by the various names by which myalgia has been known, the principal theories advanced to account for the morbid manifestations are three in number: (1) that the malady is a rheumatism of the muscles; (2) a form of neuralgia; (3) an inflammation.

(1) Muscular Rheumatism.—That this affection should be popularly associated with rheumatism is not surprising when the character of the pain is regarded, its aggravation on movement, and the temporary or permanent crippling which it occasions; especially when we call to mind the exceedingly vague and indefinite ideas which prevail in regard to rheumatism. But that it should be looked upon, far and wide, among physicians as a form of rheumatism, and described as such in the systematic works—that it should be regarded as due to the same causes as rheumatism and treated from that point of view—is certainly as remarkable as it is misleading.

Let us look at the facts. Nothing is easier: the two affections are under our daily observation side by side; in this climate and among working people few maladies are more common.

On the one hand we behold a constitutional disease with widespread manifestations—a special joint inflammation, which tends neither to the deposit of urate of soda nor to suppuration; a peculiar acid secretion from the skin; highly acid urine; a notable tendency to inflammatory heart complications; marked pyrexia. We observe also a marked disposition to recurrence and to the hereditary transmission of the diathesis.

The phenomena of rheumatism may be ill defined; that is to say, the attack may be subacute, but the features are the same; or they may linger and assume the chronic form, in which fever is replaced by a peculiar alteration in the fluids of the body, showing itself in a dull anæmic complexion and a greasy skin; but in all cases the seat of the disease-signs is in the joints; it is articular.

On the other hand, myalgia is not a general malady nor the expression of one. It is scarcely a disease at all. It is purely local. A muscle or a group of muscles, overworked, cry out, and this cry is interpreted by the sensation of pain. It is to be borne in mind that the overwork may be absolute, or merely relative to the healthfulness of the muscle at the time. In either case there is a derangement between the balance of work and nutrition in the muscle. The secretions are not altered; there is no sweating; the urine presents no abnormal conditions. Endo- and pericarditis never occur as complications; fever is absent.

The attack is often light, and quickly passes away. If it become chronic, further nutritive changes take place. The muscle becomes rigid, and often atrophies. According to Froriep and Virchow, as quoted by Jaccoud² and Niemeyer,³ the fasciculi are beset here and there with thickened connective tissue. Vogel observed in several chronic cases the neurilemma of the nerves supplying the part to be thickened, hardened, and adherent.

² Traité de Pathologie interne, Paris, 1871.

³ Lehrbuch der Speciellen Pathologie und Therapie, Berlin, 1871.

In all cases the affection limits itself to the muscles. The joints remain free. When they undergo changes it is after a long time and as a result of want of use or of reflex disturbances of nutrition through the nervous system. Nothing is known of hereditary predisposition to myalgia. In the manifest tendency to recur in the same individual it and rheumatism are alike. In all essential points their clinical resemblance is of the most superficial kind. It is clear, then, that the processes which give rise to the phenomena of rheumatism do not directly affect the muscular system.

The credit of having first formulated this opinion, previously only vaguely recognized, is due to Roche and Cruveilhier,⁴ but Valleix, Garrod, Flint, and other writers, who describe myalgia under the head of muscular rheumatism, coincide in this view. Even the statement that the two diseases are constantly associated is not borne out by the results of extended clinical inquiries. My own observation has not confirmed it. Of 7 cases⁵ taken at random to illustrate a point of treatment, 1 had followed an attack of rheumatic fever; 1 occurred in an individual who had many years before suffered from rheumatism; and 5 gave no history whatever of that disease: 1 followed tonsillitis. DaCosta⁶ details 2 cases of myalgia—1 in the loins (lumbago), associated with bronchitis or following it, the other occurring during an attack of rheumatic fever and having its seat in the muscles of the neck. In the latter case the constitutional disease yielded to treatment which had no effect upon the local malady. Even were the association much more frequent than it is found to be, the fact would by no means establish a common causation, seeing that myalgia follows other diseases which impair the nutrition of the body. It is worthy of note that the groups of muscles most frequently involved in cases which happen during or after acute diseases are those which must work perforce—those which maintain the equilibrium of the body or carry on respiration, etc. Hence we see wry neck, lumbago, pleurodynia associated with other diseases; affections of the muscles of the extremities after overwork pure and simple.

⁴ Dict. de Méd. et de Chir. prat., article "Arthrite."

⁵ Philada. Med. Times, Nov. 7, 1874.

⁶ Penna. Hospital Reports, vol. i.

(2) Neuralgia.—Many observers have regarded myalgia as a neuralgia, having its seat in the muscles. Valleix⁷ wrote as follows: "Muscular rheumatism and neuralgia have, in the correspondence of their symptoms, their course, their exacerbations, in the absence of appreciable anatomical lesions, the greatest resemblance to each other. These affections often pass the one into the other.... The pain, which is the capital symptom of neuralgia, expresses itself, according to our observation, in three ways: If it remain concentrated in the nerves, characteristic isolated painful points are found; here is neuralgia properly so called. If the pain is diffused among the muscles, muscular action is principally painful; we have muscular rheumatism. Finally, if it be spread out upon the skin, an excessive sensibility of the cutaneous surface results, and there exists a dermalgia. These three forms of an affection which is the same may all be present at the same time, or two and two—neuralgia and dermalgia, neuralgia and rheumatism, rheumatism and dermalgia." No wonder he found nothing more difficult than to trace with exactitude the picture of this malady.

⁷ Loc. cit.

Flint⁸ also regards myalgia as closely allied to neuralgia, and states that, "being one of the neuroses, it has no anatomical characters." It is not difficult to trace the results of this teaching in the widespread confusion prevalent in regard to some very common painful affections, as, for example, that painful form of stitch known as pleurodynia, and the still more distressing gastrodynia. Even those observers who refuse to class these affections as rheumatic are too often at a loss as to whether they are neuralgic or purely muscular. Anstie⁹ has concisely contrasted the most important characters of neuralgia and myalgia in a way that strongly urges the clinical differences between them, as follows:

NEURALGIA.	MYALGIA.
Follows the distribution of a recognizable nerve or nerves.	Attacks a limited patch or 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 acquired nervous temperament, which is obvious.	As often as not occurs in persons with no special tendency.
Is much less aggravated, usually, by movement than myalgia is.	Is inevitably and very severely aggravated by every movement of the part.
Is at first accompanied by no local tenderness.	Distinguished from the first by localized tenderness on pressure as well as on movement.
Points douloureux, when established at a later stage, correspond to the emergence of nerves.	Tender points correspond to tendinous origins and insertions of muscles.
Pain not materially relieved by any change of posture.	Pain usually completely, and always considerably, relieved by full extension of the painful muscle or muscles.

⁸ Practice of Medicine.

⁹ Neuralgia and Diseases that Resemble it.

(3) Inflammation.—That the muscular affection under consideration should have been referred to morbid processes of an inflammatory kind is very natural. The use of the term myositis embodies this view, which is held, among others, by Garrod. This author defines muscular rheumatism as "an affection of the voluntary muscles of an inflammatory nature (?), but unaccompanied with swelling, heat, redness, or febrile disturbance." He assigns the combined influence of cold and damp as a cause, especially when associated with over-use of the muscles.

Though some of the gross characters of inflammation are wanting, and the course of acute cases of myalgia is toward a speedy resolution, there are several features of the affection which strongly suggest its inflammatory origin. At all events, the view that the essential pathological conditions consist in a hyperæmia with slight serous exudation, or a partial paralysis of vaso-motor nerves with escape of serum into the intimate tissues of the muscles, has, from a clinical standpoint, much to support it. In the absence of knowledge derived from the actual investigation of the morbid tissue-changes in all the stages of the affection some value is to be accorded to the following facts as confirmatory of this opinion:

It is a local affection; the onset is usually sudden; there is often, from the beginning, a slight but obvious fulness of the muscle; tenderness is present as well as pain; in chronic cases inflammatory increase of connective tissue occurs, with changes in the nerve-sheaths and fatty degeneration of muscle-substance. Moreover, the permanent contraction (contracture) which sometimes finally sets in is the same as that which follows true inflammation of muscles after injuries (traumatic myositis¹⁰).

¹⁰ Erb, Ziemssen's Cyclopædia, vol. ix.

It is uncertain whether the nerves supplying the muscles are thrown into morbid action by changes in the muscular fibres and in their sarcolemma, or by simultaneous changes in their own neurilemma. However it arise, irritation of sensory nerve-twigs is present, giving rise to pain, along with irritation of motor filaments, which occasions spasm.

It is probable that the ultimate cause of the irritation within the muscular mass, whatever it is, is common to all cases, and that when myalgia occurs in a healthy man after extraordinary muscular effort or exposure to cold damp when fatigued, or in a delicate child who has played too long, or in a poorly-fed weaver working long hours over his loom, or in the consumptive whose cough gives him no rest, or in connection with any chronic disease or acute disease, whether tonsillitis or bronchitis or fever or rheumatism, it is the same thing—the expression of muscles or groups of muscles overworked. It is not a disease; it is not a symptom of disease. It is an accident of many diseases—of any disease that lowers nutrition. And it is not less an accident of health when such muscular effort is demanded as is beyond the capacity of health.

The essential pathology of myalgia is obscure. It is not an inflammation, as that term is generally understood, but there is ground for the opinion that the lesions are of the nature of a subinflammatory process within the muscle. The not uncommon instances in which an injury or contusion—in short, traumatism—has been followed shortly after the recovery by severe myalgia are of further value as illustrating this theory.

The obstacles in the way of precise histological investigation in cases of acute myalgia are so great that it seems probable that further knowledge is to be reached for the most part by way of clinical work.

DIAGNOSIS.—The fundamental question for consideration in this place is whether we are dealing in any given case with local manifestations of a constitutional disease or with purely local phenomena. That the latter is the correct view seems to the writer to admit of no further discussion in this article. This position being assumed, and due regard having already been paid to the differential diagnosis between myalgia and rheumatism, neuralgia and inflammatory myositis, it seems useless to enter upon the consideration of the diagnosis between this and other painful affections to which it bears but slight and superficial resemblances. Spinal irritation, hypochondriasis, locomotor ataxia, alcoholism, syphilis, gout, and lithiasis are on the one hand attended by pains which are clearly not myalgic in character, and on the other hand peculiarly predispose those subject to them to this affection of poorly-nourished and easily-overworked muscles. Each of these diseases, however, presents a complexus of symptoms in which that which is essential and characteristic is readily to be distinguished from that which—as myalgia—is accidental.

A few words concerning the diagnosis of some of the varieties may not be amiss.

In pleurodynia the ordinary physical signs of pleural, pulmonary, and cardiac disease are absent, the painful points characteristic of intercostal neuralgia are not found, and there is little or no constitutional disturbance.

The diagnosis of myalgia lumbalis is, as a rule, unattended by difficulty. The muscular pain in the loins is characteristic. It is greatly increased by efforts to rise or to turn in bed, and is associated with diffused slight tenderness upon pressure, but never with the acute localized soreness of neuralgia or abscess. The practitioner must, however, guard against the danger of mistaking the back pains of more serious affections for lumbago by the careful examination, in all cases, of the back and abdomen, and by the investigation of the condition of the urine. The possibility that pain in this region may be caused by spinal meningitis, lumbar abscess from spinal caries, sciatica, inflammatory affections of the hip-joint, renal calculus, perinephritis, abdominal aneurism, diseases of the pelvic viscera, and the onset of certain of the acute infectious diseases must not be overlooked.

PROGNOSIS.—Under satisfactory conditions as regards hygiene and treatment the prognosis is always favorable. It becomes in chronic cases unfavorable as regards complete recovery when by reason of poverty, unhealthy occupations, unwholesome surroundings, or established wasting diseases the nutrition of the muscles and their physiological rest are permanently interfered with, and the balance between their power and work permanently deranged.

TREATMENT.—The indications are threefold: (a) relief of pain; (b) physiological rest for the affected muscles; (c) restoration of the balance between the nutrition of the muscle and the work it has to do.

(a) Relief of pain is often secured by rest in a posture that permits the complete relaxation of the muscles involved. In acute cases due to overwork pure and simple, and where complete rest is attainable, little other treatment is required. In the course of a few hours or days the function of the muscles is fully restored and their contractions are performed without pain. Where, however, complete muscular relaxation is impracticable or fails to afford relief, anodynes are necessary. Morphine hypodermically is very useful, but this altogether independently of any local action. Continuous dry or moist heat by means of flannels, flaxseed poultices, spongio-piline, etc. may be applied. Various anodyne lotions are useful. Liniments containing aconite, belladonna, chloroform, or chloral also afford relief. The compound belladonna liniment of the British Pharmacopoeia is especially to be recommended. So also are plasters of belladonna, conium, and mustard. Galvanism occasionally gives prompt relief. The same statement may be made of the use of static electricity. The pain sometimes disappears under gentle and long-continued massage.

(b) Rest is usually enforced by the intensity of the pain attending movement. In severe cases the bed is a necessity. In affections of the respiratory muscles, as pleurodynia, firm support of the side, by means of overlapping strips of plaster drawn from the spine downward and forward in the direction of the ribs to the median line in front, is sometimes necessary and always comfortable.

(c) The balance of nutrition is restored by rest. Local means to further this end are such as relieve pain—heat, anodyne and stimulating frictions, massage, and galvanism. The parts must be protected from sudden changes in temperature by extra thicknesses of flannel or sheets of wool or cotton batting—if necessary covered with a piece of oiled silk or fine gum-cloth. In old cases prolonged massage with passive movements, shampooing, and the slowly interrupted galvanic current, alternating with rapid faradic currents, are followed by good results.

As a constitutional measure a Dover's powder at night, followed by mild purgation in the morning, is often indicated. Purgation is especially called for in plethoric or gouty persons, in whom also Turkish or vapor baths are of great service, while poorly-nourished, anæmic subjects demand quinine, iron, lime, and cod-liver oil. If the attack linger, full doses of ammonium chloride, and in old cases potassium iodide in moderate doses well diluted and long continued, are advocated; and in stubborn cases Anstie recommends deep acupuncture of the muscle near its tendinous attachment. In cases marked by a tendency to spastic rigidity the repeated hypodermic injection of atropine may often be relied upon as the speediest means of cure.

Where the general nutrition is poor the local trouble is apt to be obstinate, and often yields only to measures that restore the general health.

PROGRESSIVE MUSCULAR ATROPHY.¹

BY JAMES TYSON, A.M., M.D.

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¹ From the view taken by the author as to the nature of the disease under consideration, it is evident that its proper position would be under affections of the nervous system. But as this view has not been established to the satisfaction of all who have studied the disease, it seems appropriate to place it in the intermediate position selected for it by the Editor, between muscular and nervous diseases.

SYNONYMS.—Chronic anterior poliomyelitis; Spinal form of progressive muscular atrophy; Adult form of progressive muscular atrophy; Wasting palsy (Roberts); Cruveilhier's atrophy; Amyotrophia spinalis progressiva (Erb).

DEFINITION.—Progressive muscular atrophy is a gradually progressive wasting of a group or groups of voluntary muscles, independent of primary functional inactivity and of local lesion to nerve or muscle.

HISTORY.—We are indebted to William Roberts² for the best historical account of this disease up to the date of publication of his monograph. Van Swieten seems to have described the first case, in 1754, but without comment. Cooke in his work On Palsy,³ published 1822, relates a case which had been under the care of Cline—that of an officer, first attacked in 1795. Caleb H. Parry⁴ reported another case in 1825, and Sir Charles Bell⁵ three cases in 1830. Abercrombie described a marked case in 1828,⁶ Dorwall⁷ three striking cases in 1831, and Herbert Mayo⁸ two evident cases in 1836. In 1849, Duchenne presented to the Institute of France his memoir on Atrophie musculaire avec Transformation graisseuse. In the next year Aran published his essay entitled Recherches sur une Maladie non encore décide du Système musculaire (Atrophie musculaire progressive),⁹ in which he claimed priority in description. He reported in all eleven cases, and regarded it as a primary muscular affection. Aran's researches were very important, and have caused his name to be intimately associated with the disease along with that of Duchenne.

² An Essay on Wasting Palsy, London, 1858.

³ London, 1822, p 31.

⁴ Collected Works, London, 1825, p. 523.

⁵ The Nervous System of the Human Body, London, 1830.

⁶ On the Brain and Spinal Cord, 1828, p. 419.

⁷ London Medical Gazette, vol. vii., 1830-31, p. 201.

⁸ Outlines of Human Pathology, London, 1836.

⁹ Archives générales de Méd., t. xxiv., Sept. and Oct., 1850.

Cruveilhier's studies were commenced as early as 1832, but his results were not published until March, 1853,¹⁰ when he read his memoir before the Academy of Medicine of Paris. He seems to have made the first autopsy, and was much surprised at the absence of any apparent lesion of the spinal cord. So enthusiastic and so exhaustive was his study of the disease that his name, too, has become almost inseparably associated with it, and the term Cruveilhier's atrophy is one of those by which it is known. He concluded from his earlier autopsies that the lesions were solely in the muscular system, which is progressively destroyed, while the brain and spinal cord may remain perfectly normal. In a later case (his third), terminating January, 1853, he found atrophy of the anterior roots of the spinal nerves, and then concluded that the disease resided "not in the muscles themselves, but in the anterior roots of the spinal nerves." But after the termination of his fourth case, in which an autopsy was also secured, he placed the primary lesion in the gray matter of the cord, whence he considered the anterior roots take their origin.

¹⁰ Ibid., May, 1853, p. 561.

Thouvenet,¹¹ an interne of Cruveilhier's, published in 1851 a thesis based on some cases collected in the Charité, and was the first to claim that the disease resides primarily in the peripheral nerves, and that it must be classed among rheumatic affections.

¹¹ Gaz. des Hôp., Nos. 143 and 145, 1851.

In December, 1851, E. Meryon¹² read a paper before the Medico-Chirurgical Society of London entitled "Granular and Fatty Degeneration of the Voluntary Muscles." His observations appear to have been made quite independently of any preceding researches. He argues that the primary morbid change is a default of nutrition in the muscular fibres.

¹² Med.-Chir. Trans., vol. xxxv. p. 73.

Subsequently, cases were published in 1853 by Bouvier, Landry, Burg, and Niepce in France; in 1854 by Chambers in England, Guérin and Robin in France, Cohn, Virchow, and Betz in Germany, and by Schneevogt in Holland; in 1855 laborious essays were published by Oppenheimer, Wachsmuth, and Eisenmann, and cases by Hasse, Valentiner, Virchow, Meyer, and Diemer in Germany, and Gros in France. Duchenne's work on Local Application of Electricity, also published in 1855, contains much information on the subject.

Since 1855 the reports of cases and papers on the subject have been so numerous as to make it unprofitable to enumerate them. Among the most notable are those of Eisenmann, published in Canstatt's Jahresbericht for 1856; Roberts's classic work on Wasting Palsy, in 1858; the papers of Lockhart Clarke in 1866 and 1867,¹³ and of Swarzenski in 1867;¹⁴ Kussmaul's clinical lecture¹⁵ and Friedreich's treatise¹⁶ in 1873; and Eulenburg's article on "Progressive Muscular Atrophy" in Ziemssen's Cyclopædia of Practical Medicine, published in German in 1875 and in English in 1877. An important case, in consequence of the careful post-mortem study of the nervous tissues, is one recently reported by Wood and Dercam.¹⁷

¹³ Med.-Chir. Transactions, xlix., 1866, p. 171, and l., 1867, p. 489.

¹⁴ Die Progressive Muskelatrophie, Berlin.

¹⁵ "Ueber die fortschreidende Bulbärparalyse und ihr Verhältniss zur progressiven Muskelatrophie." Sammlung klinische Vorträge, liv.

¹⁶ Ueber progressive Muskelatrophie, über wahre und falsche Muskelhypertrophie, Berlin, 1873.

¹⁷ Therapeutic Gazette, March 16, 1885.

ETIOLOGY.—The cause of this affection in a large number of cases is quite unknown. That hereditation plays an important part seems well determined by numerous observations, among which may be mentioned those of Roberts, Friedreich, Hemptenmacher, Trousseau, Meryon, Eulenburg, Sr. and Jr., Naunyn,¹⁸ Hammond, and Osler.¹⁹ In the Farr family, reported by Osler, 13 individuals in two generations have been affected, 6 females and 7 males—a larger proportion of the former than is common in this disease. Of these 9 had died at date of publication of paper. With the exception of two, all occurred or proved fatal after the age of forty. Of the 10 instances in the second generation, 5 are the offspring of males and 5 the offspring of females. The disease has not yet appeared in the third generation, which promises between forty and fifty individuals, several of whom are over thirty years of age.

¹⁸ Berliner med. Wochenschrift, Nos. 42 and 43, 1873.

¹⁹ Archives of Medicine, vol. iv., No. 3, Dec., 1880.

The over-use of the muscles involved seems to be a well-determined cause in certain cases of true muscular atrophy. The following interesting illustrations are given by Eulenburg:²⁰ Betz observed atrophy of the side three times in the cases of smiths and saddlers, who had to do heavy work with the right hand; Gull, in a tailor after excessive exertion; Hammond reports a case apparently due to excessive use of one thumb and finger in playing faro; Friedreich, one of a dragoon who may have exhausted his left hand in holding the bridle while riding; another in a morocco-leather worker, who used to press hard with his left hand; and a musician who played several hours a day on the bass viol. Schneevogt names two cases of primary atrophy of the shoulder-muscles, especially of the deltoid of the right side—one of a sailor who had to pump for days together on a leaking ship, and the other of the left side in a woman who always carried her child on the left arm while suckling it. Continued threshing and the handling of a musket have both been followed by it in the muscles called into play by these exercises. Roberts was able to trace the effects of over-muscular exertion in producing the disease in 35 out of 69 cases. As a determining cause, at least, therefore, we must admit the over-use of muscles.

²⁰ Op. cit.

There is reason to believe, too, that this form of atrophy is one of the consequences of senility—that the tendency to connective-tissue overgrowth which characterizes old age operates to produce, in a way to be presently explained, an atrophy of groups of muscles. In a woman aged seventy, now under my care, the fingers of both hands are clawed—became so inappreciably almost, and the condition is still increasing.

In addition to the above-named causes, long-continued exposure to cold, and especially to the action of very cold water, has been named. Traumatic influences, such as injuries to nerve and muscle, have been called upon to account for localized and progressive atrophy, but these are excluded by our definition from the category of true progressive muscular atrophy.

Cases have also occurred in the course of convalescence. Typhoid fever, rheumatism, measles, scarlet fever, cold during salivation, vaccination, childbed, excessive venery, syphilis,—have all been held responsible for a certain number of cases.

AGE AND SEX.—In examining the literature of acute muscular atrophy it is found that cases are reported at all ages. Thus, Wachsmuth, quoted by Eulenburg, found among 49 cases 13 under the age of fifteen, 8 from fifteen to twenty, 22 from twenty to fifty, and only 6 over fifty years. On the other hand, Roberts—who, following Aran, divides the disease into the general form and partial form—says the latter very rarely falls on individuals under adult age or over fifty, while the average age of the instances of the partial form studied by him was thirty-two years and four months. In 10 instances of the general form the patients were under twelve, and 2 more are reported as children; 1 was said to be sixty-nine and another fifty-four, the average being twenty-eight years and three months. Of Eulenburg's own cases, 7 acquired the disease before the age of ten, 6 before the twentieth year, 2 before the thirtieth, 8 before the fortieth, 5 before the fiftieth, and none later. The latter observer also finds that whenever the disease is hereditary it occurs earlier, usually before the close of the twentieth year. This was certainly not the case in the Farr family, reported by Osler.

I am inclined to believe, especially in the light of Charcot's²¹ and of Erb's²² recent studies, that the true spinal form of progressive muscular atrophy is a disease of adult life, and that the majority of cases reported as occurring in early life are instances either of what Erb calls the juvenile form of progressive muscular atrophy or of pseudo-hypertrophic paralysis.

²¹ "Revision nosographique des Atrophies musculaires progressive," Le Progrès méd., No. 10, 1885, i. 314-335.

²² "Ueber die Juvenile Form der Progressive Muskelatrophie und ihre Beziehungen zur sogenannten Pseudohypertrophie," Deutsches Archiv für klin. Med., xxxiv. 1884, S. 467.

As to sex, males predominate. Thus, according to Friedreich's statistics, out of 176 cases but 33 were females, or about 19 per cent. Of Roberts's collection of 99, 84 were males and 15 females. Of 28 cases noted by Eulenburg, 17 were in men and 11 women. This is doubtless owing to the fact that men are subjected to the causes of the disease more than women. For Roberts early noted that women who engage in needlework, washing, and household service are apparently not less liable than men similarly employed, and he found that of those whose labor did not press excessively on any particular sets of muscles females formed even a majority of cases.

Some singular freaks of selection have presented themselves in the matter of sex, particularly in the cases which have been ascribed to hereditation. Thus it will sometimes attack only the male members of a family. A remarkable instance of this was observed by Meryon, in which four sons were attacked and six daughters remained unaffected; and, again, two boys were attacked and two sisters escaped. This may occur also independent of hereditation. Occasionally the reverse takes place, the sisters only being attacked, while the brothers escape.

PATHOLOGICAL ANATOMY AND HISTOLOGY.—Two principal seats of change have been found to exist in connection with progressive muscular atrophy. The first and easiest recognized is, of course, the alteration in muscles; the second, that in the nervous system.

The muscular change is simple, and affords a typical instance of what is known as numerical atrophy. The muscular fasciculi one after another undergo fatty metamorphosis, succeeded by absorption of the resulting fat and substitution of connective tissue. The rate of atrophy varies, but sooner or later the muscle is more or less substituted by fibrous bands and cords, over which may be traced reddish lines which represent muscular tissue in a normal state.

The rationale of these changes has not been always the same. The older observers regarded them as the result of a primary fatty metamorphosis of muscular fasciculi, followed by absorption of the resulting fat. Later it was asserted that the atrophy is secondary to a myositis or inflammation of muscle, beginning as a hyperplasia of the interstitial connective tissue in its finest ramifications between the single primitive fibrils. Along with this are seen the results of irritation in the primitive bundles themselves, shown by swelling and multiplication of the muscular corpuscles, proliferation of their nuclei, and sometimes cloudy swelling. Even hypertrophied muscular fasciculi and dichotomous and trichotomous subdivision have been noted by Friedreich.

It sometimes happens that the hyperplastic process in the intermuscular connective tissue is succeeded by a fatty infiltration of the cells of the connective tissue, and there results a lipomatosis which is invariably outside of the muscular fasciculi and between them. This gives rise to an appearance of hypertrophy which is only apparent, for the muscular fasciculi are themselves wasted, and proportionally paralytic. This is seen to occur particularly in the muscles of the calves of the legs, in which is produced an appearance identical with that in the disease known as pseudo-hypertrophic muscular paralysis, with which, indeed, the condition under consideration is considered by some identical. But although we must admit in certain cases a complication of a certain degree of lipomatosis with progressive muscular atrophy, the two diseases are essentially different; and it is quite likely that in some instances pseudo-hypertrophic muscular paralysis has been mistaken for progressive muscular atrophy.

The changes in the nervous system are not nearly so simple. They have been noted in the peripheral nerves, both in their trunks and in their intermuscular branches; in the anterior roots of the spinal nerves; and in different parts of the spinal cord, including the central gray matter, the antero-lateral and posterior columns; also in the sympathetic system. These nerve-changes are not simultaneous, nor have they been discovered in every case. It is a noteworthy fact, however, that as methods of examination have improved and the manipulative skill of observers has increased the number of negative cases has diminished.

First, as to alterations in peripheral nerves in their ultimate distribution: The character of these is of a kind usually described as irritative; that is, there is a hyperplastic process in the connective-tissue sheaths (neurilemmæ) and their internal prolongations, consisting in nuclear proliferation and thickening of the tubular membrane or sheath of Schwann. Varicose distortion of the medullary sheaths and their subsequent disappearance, together with destruction of the axis-cylinders, also occurs.

The changes in the peripheral nerve-trunks, as studied in the median, ulnar, radial, and musculo-spinal, are essentially the same, resulting in thinning of the diameters of the nerves. These changes, however, are by no means constant.

The anterior roots of the spinal nerves exhibit alterations in a large number of instances. Cruveilhier called attention to them in the celebrated case of the rope-dancer Lecomte. At the autopsy, the brain, the cord, and posterior roots were found normal, but the anterior roots, from the point of exit to where they unite with the posterior, were greatly atrophied. In another case the anterior roots were to the posterior in thickness, in the cervical region, in the ratio of 1:10, while the normal ratio is 1:3; in the dorsal region as 1:5, while the normal is as 1:1½ or 2. The posterior roots, brain, and cord were again unchanged. Up to 1876, Eulenburg had collected 26 cases in which this alteration existed, and 19 in which it was absent. In the case of Wood and Dercum, referred to, this atrophy of the anterior nerve-roots existed, making 27 positive cases and 19 negative.

We come, finally, to the spinal cord as the seat of changes, and we are met by Eulenburg's statistics, according to which, up to the date of his article, there were 34 cases of positive disease and 15 negative. To the former we have again to add the case of Wood and Dercum, making 35 against 15. These alterations are by no means constant as to seat and character. Thus, Valentiner, who seems to have been the first after Cruveilhier, in 1853, to record any, found in 1855, in the centre of the cord, in the neighborhood of the three lowest cervical and upper dorsal nerves, that the elements in the region of transition from gray to white substance were obliterated, and the softened place contained numerous compound granule-cells. Schneevogt also found a softening of the cord from the fifth cervical to the second dorsal nerve, Frommann described a red softening from the medulla oblongata downward, involving chiefly the anterior and lateral columns, and especially the commissures and the innermost parts of the anterior columns lying next the commissure.

Luys found the gray matter in the neighborhood of the cervical enlargement full of hyperæmic vessels, which were surrounded with granular masses (compound granule-cells?). The same granular masses, together with numerous corpora amylacea, were scattered throughout the gray substance. The ganglion-cells of the anterior cornua had almost disappeared in the part affected, and appeared to be replaced by the granular masses. Here and there a few ganglion-cells could be recognized in a state of retrograde metamorphosis, pigmented and bereft of their polar prolongations. In this case the degeneration affected principally the left anterior cornu, and it was the left side of the body which was affected by the atrophy. The anterior roots of the spinal nerves on the left side were also atrophied. Lockhart Clarke found essentially the same changes in no less than six cases, and Duménil, Schueppel, Hayem, Charcot (six or seven autopsies), Joffroy, and lately Wood and Dercum,²³ have added others. The last two observers found changes in the lower portion of the cervical enlargement of the cord, and state in the report of their case that "in the anterior cornua of the gray matter there is a marked diminution in the number of nerve-cells. Of the three groups of these cells, the anterior has almost entirely disappeared, the lateral group is represented by but a few individual cells, while the internal group seems to have undergone a less marked change. All of these cells, with the exception of a few in the internal group, appear shrunken, and are evidently much diminished in size. They have lost in great part their polygonal shape, many of them being fusiform, and present but few processes. Only in the internal group are these cells in any way approaching the normal type, and these are few and seen in only a few of the sections. They present the characteristic size and numerous processes of the typical motor-cell, while they disclose a well-defined nucleus and nucleolus. In the atrophied cells the nuclei can only be distinguished with difficulty.

"The neuroglia of the anterior cornua is increased in amount; the vessels appear shrunken, with thickened walls and large perivascular lymph-spaces.

"In the lumbar cord the cells in the anterior cornua appear normal: in this respect the lumbar cord is in marked contrast with the cervical."

²³ Loc. cit.

Another class of cases recorded by Gull,²⁴ Schueppel and Grimm, Hallopeau and Westphal, consist in dilatation of the central spinal canal with more or less complete destruction of the gray substance, and in Grimm's case hyperplasia of the connective tissue in the white substance along with increase of the axis-cylinders. The nerve-roots were in a state of fatty degeneration, especially the finer fibres of the anterior roots.

²⁴ Guy's Hospital Reports, 1862.

Still another set of observations discovers a degenerative atrophy of the white columns only of the cord, sometimes the antero-lateral columns and sometimes the posterior. Virchow, Friedreich, and Swarzenski each found typical gray degeneration of the posterior columns, in one instance recognizable by the naked eye. Atrophy of the antero-lateral columns was noted by Frommann and Baudrimont; atrophy of the antero-lateral columns, conjoined with inflammatory changes in the gray substance and atrophy of ganglion-cells, by Duménil; changes in the antero-lateral gray substance and posterior columns by Clarke. Changes have even been found in the posterior cornua and posterior nerve-roots in a few cases, although not confined to them.

Finally, the lesions of this singular disease have been sought also in the sympathetic, and not without some success. Eulenburg's analysis discovered 5 positive observations and 14 negative ones. To the positive must be added the case of Wood and Dercum, who reported a marked increase in the amount of connective tissue and a granular state of the ganglion-cells without diminution in number. Among the changes in the sympathetic were thinning of its trunk and of the two upper ganglia observed by Swarzenski, and advanced fibrous fatty change of the cervical and thoracic portion, with abundant hyperplasia of connective tissue, disappearance of nerve-fibres and regressive metamorphosis of ganglion-cells by Duménil.

PATHOGENY.—We come now to consider the relation of these changes to the muscular atrophy which constitutes the conspicuous symptom of the disease. There are three possible views of the pathology of this affection. According to one, it is a muscular or myopathic disease in the strict sense of the term. Such muscular disease may be primarily inflammatory, a myositis—as Friedreich sought to prove in his great work—followed by fatty metamorphosis of the sarcous substance and subsequent absorption of the fat; or it may be a simple fatty metamorphosis. According to a second view, it is primarily an affection of peripheral nerves or of the anterior roots of the spinal nerves, with secondary muscular atrophy. According to a third, it is a disease of the spinal cord, and more particularly of the anterior cornua of the gray matter—a poliomyelitis anterior.

A careful study of the morbid conditions as described in the various cases reported leads me to adopt the last view. In the first place, the number of instances of positive disease of the spinal cord exceed those of any other seats of alteration, and although the changes do not always involve the anterior cornua, yet it will be noted, from an examination of the foregoing paragraphs, that a decided majority involve either the anterior cornua alone or these in connection with the antero-lateral columns, the number of cases of disease of the antero-lateral columns alone or of the posterior columns and posterior nerve-roots being very limited. Again, the number of instances in which lesions of the anterior cornua are found increases as our means of accurate investigation improve.

If we add to these considerations the fact that the symptoms are best explained by such a view, little more seems required to establish it. Recalling the well-known observation of Waller, confirmed by Bernard and others, that after section of the anterior root of a spinal nerve the distal end wastes, while the central end remains intact, because it is still connected with its own trophic centre, we have in this the explanation why atrophy of the anterior roots is also so common a symptom in progressive muscular atrophy. The fibres of the anterior roots arise from the cells of the anterior cornua, and disease of the latter must unfavorably influence the nutrition of the former; hence their atrophy. This atrophy of motor nerve-filaments is continued into the mixed nerves distributed to muscles, but is less easily demonstrable by reason of the gradually diminishing size of the nerve-trunks and by the fact that they are united in the mixed nerve with the sensory fibres from the posterior roots, which do not suffer atrophy. In consequence of the degeneration of these nerves follows degeneration of the muscles to which they are distributed, so that the alterations in the latter are altogether secondary.

From this point of view the disease in question is to be regarded as a chronic form of poliomyelitis anterior, while the essential infantile paralysis of Rilliet and Barthez would correspond to the acute form of the disease.

The association of changes in the anterior roots with others in the spinal cord may be explained either on the ground of extension by continuity to adjacent parts, or on that of coincidence. In illustration of the latter I may refer to a case recently reported from Mendel's clinic²⁵ in Berlin, in which the symptoms of progressive muscular atrophy were associated with those of tabes dorsalis or progressive locomotor ataxia. Here it is not unlikely that the coincidence is merely accidental; and this was Mendel's opinion in this case. In other instances the involvement of other portions of the spinal cord may be a result of an extension of the disease from its true seat, while many cases described as progressive muscular atrophy are not such at all, but are in part the result of other affections of the spinal cord. It is evident, also, that this order may be reversed, as in a case reported by Eulenburg²⁶ to the Berlin Medical Society.

²⁵ Philada. Medical News, Sept. 12, 1885, p. 188.

²⁶ Berliner klin. Wochenschr., No. 15, April 13, 1885.

SYMPTOMS.—The first distinctive symptom of the disease under consideration is the muscular atrophy or wasting. However general it may subsequently become, it is at first localized. The upper extremity is by far the most frequently involved—7 out of 9 times in Aran's cases. Sandahl out of 62 cases found the right upper extremity attacked 37 times, the left in 14 instances, and both in 11. In Friedreich's statistics it occurred first in the upper 111 times out of 146, while the lower was invaded 27 times, and the lumbar muscles 8. Most frequently it begins in some muscle or group of muscles in the right hand, either the interossei or those of the ball of the thumb. Of the interossei, the external interosseus is usually the first affected. Thence it extends to the other interossei, and soon very striking depressions make their appearance between the metacarpal bones, and the extensor tendons on the dorsum, and the flexors in the palm become as distinct as if dissected out. Succeeding this follows contraction of the flexor tendons until the picture seen in Fig. 32 is produced, in which 1 exhibits the anterior surface of the hand, and 2 the posterior.

FIG. 32.

(1) HAND, PALMAR SURFACE. (2) DORSAL SURFACE (after Duchenne). a, Ends of the metacarpal bones; b, Tendons of the flexor sublimis; c, Muscles of the ball of the thumb.

Opinion is not unanimous as to whether the atrophy when beginning in the hand involves first the thenar muscles or the interossei. Roberts, Wachsmuth, and Friedreich say that it begins, as a rule, in the thumb; Eulenburg, that it invariably begins in the interossei. From the interossei it may creep up the forearm, and thence to the arm, or it may skip the forearm and pass into the arm, although the triceps extensor muscle is usually spared. It may come to a standstill in either of those places, but may involve the muscle of the shoulder, especially the deltoid. When the latter and the arm are involved, a picture like that of Fig. 33 is produced.

FIG. 33.

Showing Atrophy of the Right Deltoid and Arm, and the Left Arm.

FIG. 34.

Showing Atrophy of the Deltoid, posterior aspect, and the Scapular Muscles.

Beginning most frequently in the right, both upper extremities become sooner or later involved.

In other instances in which the upper extremities are previously involved the atrophy begins in the shoulder, in the deltoid—here again the right first. Succeeding the deltoid, the scapular and trapezius muscles may be involved in any order, while a grotesqueness of effect is often produced by reason of certain adjacent muscles retaining their natural size or even being hypertrophied. This is particularly the case with the anterior part of the trapezius, which is almost never involved. With the shoulders first affected, the arm and forearm may retain their usefulness and strength; but the power of lifting the arm from the side, and especially of raising it above the head, is lost. And if the patient wishes to lay hold of anything, he must swing his arm forward with a jerk until it is brought in reach of his fingers, and then it must often be caught up by the pathologically hooked terminations of these.

The muscles of the trunk do, however, become at times involved—the pectorales, the latissimi, serrati, and intercostales, and even the diaphragm and abdominal and lumbar muscles. Life is seriously jeopardized when the intercostals and diaphragm are affected, in consequence of interference with respiration. If the intercostals cease to contract, the upper part of the thorax ceases to move, and if the diaphragm is involved, the epigastric and hypogastric regions are drawn in during inspiration, and talking and singing are interfered with. Even a mild bronchitis is apt to be fatal in consequence of the difficulty in expelling the secretions.

The muscular atrophy thus produced is generally accompanied by a corresponding wasting and retraction of the skin, so that this continues applied to the muscles in the usual manner. In some instances, however, this is not the case, and in these a baggy condition of the skin is added, which gives its subject an appearance which has more than once rendered him valuable to the showman as the elastic-skin man, etc. It sometimes happens, on the other hand, that the atrophy is obscured by an accumulation between the muscle and skin of adipose tissue, and an appearance of hypertrophy rather than atrophy may be produced in consequence, analogous to the same state of affairs in pseudo-hypertrophic paralysis, the relations of which disease to progressive muscular atrophy will be considered under the head of Diagnosis.

At almost any stage the disease may come to a standstill, and may continue thus for many years. The time required to attain its various degrees also varies greatly, but the spread is usually slow, requiring, as a rule, years for its completion. A general involvement of the voluntary muscles of the entire body is exceedingly rare.

As stated, the disease may begin in the lower extremity, but much more rarely. It is very seldom that the same order of invasion pursued in the upper extremity is followed in the lower—that is, beginning with the interossei. It may begin in the thigh and involve it alone, or extend to both thighs, or both legs as well. Under these circumstances weakness of the legs is a striking symptom, the patient being unable to stand, often falling down or requiring a cane or crutches to assist him. In illustration of this mode of invasion may be related one of Roberts's cases, that of an adult woman thirty-eight years old, a domestic servant, in whom at thirty-six was perceived a weakness in the right thigh. She first noticed that it grew tired sooner than the left. This gradually increased, until she was compelled to sit much of the day, then to use a stick, and finally crutches. This was accompanied by a gradual wasting of the thigh-muscles. Even in this case the loss of power was greater than would have been expected from the degree of atrophy, the loss of bulk incident to which Roberts believed to have been in part replaced by fat. In other instances, however, the extremest degree of atrophy has been noted where the disease has commenced in the lower extremities.

The deformity produced by the wasting muscle is sometimes further increased—more frequently in the earlier stages—by a painful swelling of the joints, first mentioned by Remak, called by him neuro-paralytic inflammation, and referred to the sympathetic. This may affect the small (phalangeal) as well as the larger joints (shoulder and elbow).

Cases apparently beginning in the face are reported, when the distorted expression resulting is very characteristic.

Aran first, and Roberts afterward, divided cases of the disease into two groups, the partial and general. In the former are included those involving the extremities only; in the latter become involved, sooner or later, the muscles of the trunk, neck, face, mouth, pharynx (muscles of deglutition), thorax (muscles of respiration), and even of the abdomen. Even the tongue is reported as undergoing atrophy.

General wasting palsy, as was early observed by Roberts, is unquestionably a rare disease, and in no case have all the muscles of the body been found implicated in one individual, and a few seem altogether exempted. Such are the muscles of mastication and of the eyeball, including the levator palpebræ.

A second muscular symptom, more or less distinctive, is fibrillar contraction. This consists in a wave-like contraction running along small bundles of muscular fasciculi. The contractions occur spontaneously or are excited by any slight stimulus, as a breath of air or a dash of water, or by tapping the patient, or passing a galvanic current through the parts, and at any stage of the disease, except that they do not occur in muscles wholly destroyed. Sometimes they can be felt by the patient. At other times he is wholly ignorant of them. They are not invariably present, and often they have been observed in muscles atrophied from other causes. They possess, however, a certain amount of diagnostic value, especially when spontaneous.

More rare, and less destructive, are cramps, twitches, and clonic contractions of groups of affected muscles. These, when present, are sometimes exceedingly painful.

Coincident with the wasting of muscles is their loss of function. The power of abducting and adducting the fingers gradually disappears, so also that of flexion and extension, and everywhere the loss of function goes pari passu with the atrophy. As Roberts graphically puts it, "The tailor discovers that he cannot hold his needle; the shoemaker wonders he cannot thrust his awl; the mason finds his hammer, formerly a plaything in his hand, now too heavy for his utmost strength; the gentleman feels an awkwardness in handling his pen, in pulling out his pocket handkerchief, or in putting on his hat. One man discovered his ailment in thrusting on a horse's collar; another, a sportsman, in bringing the fowling-piece to his shoulder."

Along with the atrophy of muscle and loss of power comes a gradually diminishing response to electrical stimulus. Direct muscular faradization fails first to excite contraction, and sometimes fails completely even before voluntary mobility is lost. Indirect muscular faradization continues longer to excite contraction, but it also finally fails. Response to the constant current continues still longer, but it also finally fails to elicit contractions, stronger and stronger currents being required, until finally all fail. The galvanic excitability of nerve-trunks is maintained for quite a long time, but finally also disappears. Some irregularities present themselves in this respect.

A singular electrical reaction, first described by Remak, and said by him to be of frequent occurrence in muscular atrophy, was named by him deplegic contraction. He describes it as follows: When the cathode or negative pole is put below the fifth cervical vertebra, contractions can be produced in the atrophied muscles of the arm when the anode or positive pole is placed in an irritable zone, which extends from the first to the fifth cervical vertebra, or, still better, in the carotid fossa or the triangle between the lower jaw and the external ear. The contractions always take place on the side opposite to that at which the anode is placed, while when the electrodes are placed on the median line they occur on both sides, although when the current is very weak they are limited to the muscles most seriously involved. Meyer, Drissen, and Erb confirmed Remak's statement, while Fieber, Benedikt, and Eulenburg failed to do so. Remak interprets these contractions as reflected from the superior cervical ganglion of the sympathetic. He bases this view upon the fact that the patient perceived a sensation behind the ball of the eye when the current was closed. Eulenburg, on the other hand, regards them as genuine reflex contractions, independent of the sympathetic, and caused either by excessive irritability of the central reflex apparatus or by an abnormal excitability of the muscles themselves.

Sensibility is, in many cases, unchanged, the tactile sense being as delicate as ever, and pain, except accompanying the cramps above described, is absent. At times, however, the atrophy is preceded by paroxysms, which may or may not accompany the clonic contractions referred to. It is sometimes in the course of nerve-trunks, but as often diffuse, as though the muscles themselves were its seat. At other times it is variously described as a soreness, an aching, or a rheumatic pain. Accompanying advanced degrees of the atrophy, however, there is very rarely—in 3 out of 105 cases, according to Roberts—a slight diminution of sensibility, especially in the ends of the fingers, while the faradic sensibility may be similarly diminished.

Modified sensations, as those of cold, numbness, and formication, may be experienced, and reflex excitability may be increased, while the knee-jerk is said to be absent. Unusual sensitiveness to cold is sometimes noted, and a loss of muscular power under its influence, which is again restored by artificial warmth.

Among more inconstant symptoms, denominated vaso-motor, are, in the early stages, fever and slight elevation in local temperature from 2° to 3° C. Fever is less frequently observed toward the termination of the disease, and at this stage a fall of local temperature, as much as 4° C., has been noted. In the same category of vaso-motor symptoms are classed the skin contractions already referred to, hyperidrosis or excessive sweating, and certain very rare oculo-pupillary symptoms, consisting mainly of contraction of the pupil and slow reaction, but including also, in a case reported by Voisin, flattening of the cornea on both sides and defective sight.

COMPLICATIONS.—Progressive muscular atrophy is not infrequently associated with amyotrophic antero-lateral sclerosis and with labio-glossal or progressive bulbar paralysis. Both affections may result as an extension of the disease from the anterior cornua of gray matter, the former into the antero-lateral columns, the latter into the medulla oblongata, or the affection may be primary in either of these two situations, and extend thence into the anterior cornua of gray matter.

When there is also lateral sclerosis, there is rigidity of the lower limbs in addition to the atrophy of the upper—at first temporary, but afterward permanent. This may extend to the upper also, and the arms become fixed in semipronation and semiflexion.

When there is bulbar paralysis there is difficulty in moving the tongue, in speaking, and in swallowing. The mouth remains open, the lower lip drops, the patient cannot whistle or kiss or blow out a candle; he speaks through his nose. On the other hand, the upper part of the face is natural, the orbicularis palpebrarum muscle and occipito-frontalis acting well. As a consequence, the carrying of the food back into the oesophagus is rendered difficult or impossible; swallowing is imperfectly successful; the food sometimes enters the larynx, and the patient dies of suffocation. The saliva dribbles from the mouth. Later, respiration is embarrassed, and performed principally by the diaphragm; there is difficulty in raising mucus, and if bronchitis supervenes the patient dies of suffocation, because he cannot raise the phlegm. Such was the death of Prosper Lecompte, the historic patient of Cruveilhier.

DIAGNOSIS.—As our knowledge of progressive muscular atrophy increases we realize more and more that there have heretofore been included under this name many cases which must now be relegated to other categories. If we confine the disease, as I think we must, to those cases in which there are degenerative changes in the anterior cornua of the gray matter of the cord, we must endeavor to associate with these lesions a set of symptoms which are sufficiently constant, and exclude all other similar combinations. Such a set of symptoms includes the following: insidious and progressive atrophy of groups of muscles, beginning usually in the hand or shoulder, from which, however, it may extend to others in a diffuse and rarer form of the disease. The atrophy is accompanied by a corresponding loss of power in the affected muscles and partial or complete reaction of degeneration in the same, and by fibrillar twitchings. Along with this, sensibility, the special senses, the reflexes, as a rule, and sphincters always remain normal.

This complex of symptoms is to be distinguished from the so-called juvenile progressive muscular atrophy of Erb, and from pseudo-hypertrophic muscular paralysis. In the first there is also slow, symmetrical, but intermittent and often stationary, wasting and weakness of certain groups of muscles, preferably those encircling the shoulder and upper arm, the pelvis and upper thigh and back—"an atrophy," says Erb, "which is very frequently combined with true or false muscular hypertrophy, with a peculiar toughness of the atrophying muscles, but without fibrillar contraction or any trace of the reaction of degeneration or other lesion in the body, be it of the nervous system, organs of sense, vegetative organs, or external integuments."²⁷ The average age in the juvenile form is much less, Erb's cases ranging from seven to forty-six, or an average of twenty-six and a half, while in the spinal form, or true progressive muscular atrophy, although the age is reduced by reason of the admixture of other cases than those of true progressive muscular atrophy, the average age is much greater. Of Roberts's cases, all of which seem true cases, the youngest was twenty, while the age of the remaining four was thirty-nine, forty-seven, sixty-seven, and thirty-eight.

²⁷ "Juvenile Form der Progressive Muskelatrophie," Deutsches Archiv für klinische Medizin, Bd. xxxiv., 1884, S. 471.

There are certain symptoms in common in progressive muscular atrophy, as heretofore described, and pseudo-hypertrophic paralysis; and I have already said that Friedreich and others are disposed to consider them one and the same disease; but such is not the case. First of all, while there is wasting of muscle, although obscured in the lower extremities by the fatty infiltration, and while there is loss of power, there are in pseudo-hypertrophic paralysis absolutely no alterations in the spinal cord. Pseudo-hypertrophic paralysis always begins in the lower extremities, while progressive muscular atrophy begins for the most part in the upper. Pseudo-hypertrophic paralysis is a disease of childhood, and strikingly hereditary; and while progressive muscular atrophy in its broadest application is also a disease of childhood and hereditary, it is much less so than pseudo-hypertrophic paralysis; and if, with Erb, we separate the juvenile form from muscular atrophy, progressive muscular atrophy is not a disease of childhood, while heredity is almost entirely removed from it.²⁸

²⁸ It cannot but help the reader to get a correct notion of this interesting but still somewhat imperfectly understood disease to be familiar with Erb's formulated conclusions (loc. cit., p. 510):

"There is a peculiar form of progressive muscular atrophy which is characterized by a definite location, definite course, definite behavior of affected muscles, and definite alteration in them, but without alterations in the spinal cord—the condition named by me the juvenile form. It begins in youth or childhood.

"This form agrees in its symptomatology—especially in its localization in the upper half of the body, partly also in the lower—entirely with the so-called pseudo-hypertrophy of muscles, only that in the former a decided lipomatosis leading to an increase in volume is wanting; on the other hand, true muscular hypertrophy is not infrequent in both forms of the disease.

"If this juvenile form occurs in the earliest childhood, it may in all its details be identical with pseudo-hypertrophy, except that the lipomatosis is wanting.

"The anatomico-histological alterations of the muscles are exactly the same in the juvenile form as in pseudo-hypertrophy.

"The juvenile form not infrequently occurs in entire groups in one family, producing the so-called hereditary—better named family-muscular—atrophy.

"If this juvenile-hereditary form occurs after puberty, it affects most frequently, although not exclusively, the upper half of the body. If it sets in, on the other hand, in earliest childhood, it affects preferably the lower extremities and the pelvis. Transitional forms, however, occur also in family groups.

"In the latter form, that occurring in earliest life, we have that which Leyden has proposed to designate as hereditary muscular atrophy.

"Thus, hereditary muscular atrophy is in all essential points identical with pseudo-hypertrophy, and is distinguished from it only in the slighter degree of lipomatosis of the muscles.

"All of these forms have probably nothing to do with spinal progressive muscular atrophy; they differ from it in localization and course, anatomical changes and clinical phenomena in the muscles, and alterations in the spinal cord."

Still another myopathic condition, which in the light of modern knowledge has to be separated from progressive muscular atrophy, is Duchenne's hereditary infantile atrophy. This is characterized by onset at an early age and by its beginning in the facial muscles. Its clinical features are thus described by Charcot²⁹ and his pupils Marie and Guénon.³⁰ Although it mostly begins in infancy, it may not come on until adolescence, or even until middle or advanced age; it is often hereditary; the face-muscles are first involved, particularly the orbicularis oris, and there is a peculiar expression of the countenance; whistling is impossible, and the articulation of labials difficult; the eyes cannot be completely closed or the eyebrows raised. Subsequently other muscles become involved, particularly those of the shoulder girdle, except the deltoid, the muscles of the arm, the long supinators of the forearm, and in the lower extremities the muscles of the buttocks, thighs, and of the anterior external aspect of the leg. The muscles of the hands and fingers are spared. Fibrillar tremors are not present, and there is no reaction of degeneration. The distribution of the atrophy is almost identical with that of Erb's form, except that it begins in the face. It is likewise an hereditary or family disease.

²⁹ Le Progrès médical, No. 10, 1885.

³⁰ Revue de Médecine, October, 1885.

PROGNOSIS.—The course of progressive muscular atrophy is never rapid—essentially chronic. Recovery in a well-established case is not to be expected, although it is rare for any one to die of the direct effects of the disease. It is often arrested in its course, and remains at a standstill for years. The wider its distribution and the more numerous the foci of involvement, the more rapid is its course; and when the muscles of deglutition and respiration are involved, and the carrying back of food interfered with, death from asphyxia is liable to be produced by the entrance of food into the larynx or from the accumulation of mucus in what under ordinary circumstances would be a slight catarrh of the respiratory passages.

TREATMENT.—Treatment directed specifically to the cure of the disease is limited. Only where there is reason to believe that syphilis is responsible for it do we find an opportunity to strike at the fons et origo mali by mercurials and iodide of potassium. Yet in Cooke's case, quoted by Roberts,³¹ the disease after progressing continuously for five years, during which a variety of modes of treatment was tried, had its further progress stopped by a course of mercury, although no cause of the disease could be assigned.

³¹ Op. cit., p. 1; also Cooke On Palsy, Lond., 1822, p. 31; also quoted by Graves in his Clinical Lectures, L. lxxxiii.

In the majority of instances treatment must consist merely in efforts to maintain the general health and strength of the patient and to counteract the obstinate tendency of the spinal disease to produce wasting of the muscles by depressing their nutrition. The former is accomplished by an abundance of nutritious food, fresh air, and out-door life, by gymnastics, chalybeate and other tonics, including arsenic, strychnine, and quinine. The second is attained by electricity, frictions, and massage. Both forms of electricity are useful, the induced current with rapid interruption with a view to counter-irritate and to stimulate the circulation, or by slow interruptions to stimulate individual muscles to contraction, and thus maintain their nutrition. Duchenne recommended the application of currents of moderate intensity, with not too frequent interruptions, and for a few minutes only at a time, so as not to fatigue the fibres undestroyed. He urged particularly the treatment of important muscles like the diaphragm through the phrenic nerves, of the intercostals, and of the deltoids before they were actually invaded by the disease. He relates the case of a man named Bonnard who had lost many of his trunk-muscles, and who was beginning to suffer with dyspnoea, on whom faradization of the phrenic nerves, repeated three or four times a week, was of great service, enabling him to walk considerable distances and to go up stairs without fatigue. Another patient, whose arms were much wasted, was so far restored that at the end of six months he was again able to support his family.

The direct current—galvanism—is useful in advanced stages of the disease, where even the strongest faradic currents fail to produce response. Even where galvanic currents fail to exert contractions the treatment ought to be persevered in for a long time. It may be necessary to use very strong currents at the outset, which may be gradually weakened as contractility returns.

Remak, who especially advocated the use of the continuous current, advised to place the positive pole in front of one mastoid process and the negative pole on the opposite side of the neck near the spinous processes of the vertebræ, not higher than the fifth cervical, by which he produced the contractions already described as diplegic in the fingers and other paralyzed parts.

Galvanization of the sympathetic has been apparently useful in the hands of some—viz. Roberts, Benedikt, M. Meyer, Guthzeit, Erb, Neseman, and others, while the latter reports a case of complete cure by this treatment. Eulenburg tells us, however, that a relapse is said to have occurred in this case; also that neither he nor Rosenthal have had any results from it.

Massage is equally important, and should be used at the same time with electricity, but at a different time of day. Eulenburg refers to a case which was said to have brought the disease to a standstill. There can be no doubt of the value of the measure as an adjuvant to treatment.

In families in which an hereditary tendency exists prophylactic treatment should be used. It should include hygienic measures of the kind already referred to, and the avoidance of undue fatigue and exposure; and in the selection of an occupation these matters should be kept in view.

On the supposition that the disease is a purely local one, gymnastics, involving the exercise of the groups of muscles prone to attack, would be indicated, but assume less importance from our standpoint that it is a spinal disease. At the same time, the patient should have the benefit of any existing uncertainty in the pathogeny of the affection; and as gymnastics are eminently calculated to improve the general health, and thus indirectly to avert the disease, their use is indicated on these grounds.